- Email: [email protected]
Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable ductility
Author’s Accepted Manuscript Preparation of low cost TiZrAlFe alloy with ultrahigh strength and favorable ductility S.X. Liang, L.X. Yin, L.Y. Zheng, M.Z. Ma, R.P. Liu www.elsevier.com/locate/msea
PII: DOI: Reference:
S0921-5093(15)30012-5 http://dx.doi.org/10.1016/j.msea.2015.05.067 MSA32395
To appear in: Materials Science & Engineering A Received date: 15 April 2015 Revised date: 18 May 2015 Accepted date: 21 May 2015 Cite this article as: S.X. Liang, L.X. Yin, L.Y. Zheng, M.Z. Ma and R.P. Liu, Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable d u c t i l i t y , Materials Science & Engineering A, http://dx.doi.org/10.1016/j.msea.2015.05.067 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable ductility S.X. Liang a,*, L.X. Yin a, L.Y. Zheng a, M.Z. Ma b, R.P. Liu b a
College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, Hebei, China
b
State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
Abstract Cost reducing has always been a very important future development for Ti alloys. A new series of low cost TiZrAlFe alloys with ultra-high strength and favorable ductility are developed in this work. The microstructure and mechanical properties of the new series of low cost TiZr based alloys with Fe content from 0.5 to 2.0 wt% are investigated. As Fe content increases from 0.5 to 2.0 wt%, the β to α phase transition temperature decreases from 836 to 768 °C, and the phase constitution of the examined alloys changes from α' + β to α" + β and finally whole β phase. That acicular α' martensite precipitating out of β matrix is the microstructural feature of the developed low cost alloy with Fe content of 0.5 wt%. As the Fe content increases to 1.0 wt%, the microstructural characteristic is some ultra-fine lenticular α" martensites with tens nanometers thickness enchased in β matrix. As the Fe content further increases to 1.5 wt%, the β grains generate recrystallization. Microstructural features of β grains further recrystallization and growth exhibit in the examined alloy with Fe content of 2.0 wt%. Tensile results show that the new series of low cost alloys have 1 / 18
ultra-high strength and favorable ductility. The strength of the examined alloys changes from 1495 to 1212 MPa as the increasing of Fe content from 0.5 to 2.0 wt%. Meanwhile the total elongation ranges from 8.3% to 12.4%. The strengthening mechanism of the developed low cost TiZr based alloys is also discussed. The current finding not only presents an excellent alloy with superior combination of strength and ductility but promotes the development and application of low cost Ti alloys. Keywords: Ti alloys; Low cost; Microstructure; Mechanical properties
*Corresponding author address: College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, China E-mail: [email protected] Tel: 0086-310-8577971
2 / 18
1． Introduction Titanium (Ti) and Ti alloys with numerous favorable properties such as low density, high specific strength, corrosion resistant, good mid-temperature properties, nonmagnetic, and so on, are important structural materials and have been widely used in national defense, aerospace, marine, motorsport et al fields [1]. Series high performance Ti alloys have been developed in recent decades such as ultra-high strength Ti alloys (the tensile strength over 1250 MPa) [2-4], high temperature Ti alloys [5,6] and burn-resistant Ti alloys [7,8]. However, expensive cost of Ti alloys severely limits its development. The actural dosage is much lower than that of conventional steel and aluminium alloys. Practices and researches showed that cost of expensive raw materials accounts for approximately 40% of the total cost of Ti alloys [9]. Therefore, replacement of expensive raw materials such as V, Nb, Mo with cheap raw materials like Fe, Cr, Mn et al is an effective way to reduce the total cost of Ti alloys [10-12]. Among them, the 62S
(Ti-6Al-1.7Fe-0.1Si)
[ 13 ],
TFC
(Ti-4.3Fe-7.1Cr)
and
TFCA
(Ti-4.3Fe-7.1Cr-3.0Al) [12] et al are the representative low cost Ti alloys with high performance. For now, research on low cost Ti alloys with high strength and toughness is still the important content and the development direction of Ti alloys. Attributing to the similar physicochemical properties between elements of Ti and Zr, recently developed TiZr based alloys exhibit favorable mechanical properties [14-17]. The representative Ti–20Zr–6.5Al–4V [18] and Ti–30Zr–5Al–3V [19] alloys have tensile strength over 1600 MPa, and specific strength over 340 MPa/(g/cm 3). 3 / 18
Accordingly, the TiZr based series alloys show widely applied prospect as structure materials. However, almost all of current TiZr based alloys with high performance contain expensive raw materials such as V, Nb et al [20,21]. Replacement of those expensive raw materials with low cost raw materials without loss of its strength and toughness is also important to reduce cost and promote industrial applications of TiZr based alloys. The current study aims to develop a new series of low cost TiZr based alloys by replacing of expensive raw materials with cheap Fe element. The effects of Fe content on the microstructure and mechanical properties of the TiZr based alloys are also discussed. This study will facilitate the development and actual application of low cost Ti and TiZr based alloys. 2． Experimental procedure Sponge Ti (99.7 wt%), sponge Zr (Zr + Hf ≥ 99.5 wt%), industrially pure Al (99.5 wt%), and Fe (99.9 wt%) were used to prepared the TiZrAlFe series alloys. Raw materials were melted using high-vacuum non-consumable are melting furnace in a Ti-gettered argon atmosphere. To guarantee the uniformity, each ingot was remelted at least four times. Actual alloy compositions are showed in table 1. Ingots were heated to 850 °C and held for 10 min, and then rolled into plated samples with a thickness of 4 mm. The plated samples were water quenched immediately after rolling. Hot rolled specimens were removed about 1 mm on each rolled surfaces for followed tests and analysis. Differential scanning calorimetry (DSC) was used to test the phase transition 4 / 18
temperatures using heating velocity 10 °C/min adopting the standard of ASTM: F2004–05(2010). The DSC samples were full annealed at 850 °C for 2h and cooled inside the furnace to 300 °C then air cooled to room temperature. Phase structure of hot rolled specimens was determined by X-ray diffraction (XRD) using copper Kα X-radiation (ASTM: D5380-93(2014)). Microstructure was observed through transmission electron microscopy (TEM) and Olympus DSX500 type optical microscopy
(OM).
TEM
analytic
specimens
were
prepared
by
twin-jet
electrochemical polishing in a solution of 10% perchloric acid and 90% methanol at 13 V and -30 °C. Tensile samples were machined from hot-rolled plates after removing 1 mm thick portions from both sides of the rolled surface. The size of tensile samples is shown in Fig. 1. Uniaxial tensile tests (ASTM: E8/E8M–11) were performed on an INSTRON 5982 testing machine at a strain rate of 5×10-4 s-1. The strain during the entire testing process was monitored using an extensometer with a 12.5 mm gauge length. 3． Results and discussion Fig. 2 shows the DSC curves near phase transition of the examined alloys with various Fe contents. The onset and end transition temperatures of the α phase into β phase for F05 alloy are approximately 764 °C and 836 °C, respectively. As the Fe content increases, the end transition temperature of the α phase into β phase of the examined alloys decreases gradually. While the Fe content reaches 2 wt%, the end transition temperature of the α phase into β phase of the F20 alloy decreases to 768 °C. According to the Ti-Fe [22] and Zr-Fe [23] binary phase diagrams and 5 / 18
previous results [24,25] about effects of Fe on the phase stability of Ti and/or Zr alloys, it is easy to conclude that Fe is an β-stabilizer for Ti and Zr alloys. Thus, the end transition temperature of α phase into β phase of the examined alloys decreases with the increasing of Fe content. However, the trend of onset transition temperature changed with Fe content is not consistent completely with that of end transition temperature. The onset transition temperature also decreases from 764 to 716 °C with the increasing of Fe content from 0.5 to 1.0 wt%. Nevertheless, the onset transition temperature is kept near 720 °C while the Fe content further increases from 1.0 to 2.0 wt%. Fig. 3 shows the XRD patterns of the low cost TiZrAlFe series alloys with different Fe contents. The phase compoition of the examined low cost TiZr based alloys is greatly dependent on the Fe content. The F05 alloy is composed of α' martensite and retained β phase. As the Fe content increases to 1.0 wt%, the F10 alloy consists of α" martensite and retained β phase.As the Fe content further increases to or over 1.5 wt%, the phase constitution of the examined alloys is wholy retained β phase. The phase constitution of the examined alloys with various Fe contents is showed in the table 2. Previous results [26,27] showed that the phase constitution of water quenched Ti and/or Zr based alloys will change as α' → α" / ω → β with the increasing of β-stabilizer. Based on the DSC results, the stability of β phase in the examined alloys increases with the increasing of Fe content. Consequently, the phase constitution of the examined alloys also varies with the increasing of Fe content. The lattice constants of the constituent phases in the examined alloys are also obtained 6 / 18
according to the XRD patterns and results are also showed in table 2. The lattice constant a of the α' martensite in the F05 alloy is appproximate 0.31183 nm which is higher than that of the TiZr based alloys in previous literature [16]. The key factor of that higher value is the more addition of Zr element with larger atomic radius R. From the table 2, it is easy to find that the lattice constant a of the β phase slightly decreases with the increasing of Fe content. The slightly decreasing results from the replacement of larger elements of Ti (R = 147 pm [28]) and Zr (R = 160 pm [29]) with smaller Fe (R = 126 pm [30]) element. Fig. 4 shows the OM micrographs of the examined alloys with various Fe contents. Microstructure of the examined alloys is remarkably dependent on the addition of Fe content. The microstructural feature of the F05 alloy is that acicular α' martensites presipitate out of the orignal β matrix in Fig. 4(a). As the Fe content increases to 1.0 wt%, the microstructure characteristic of the F10 alloy is featured by very fine dot or rodlet α" grains in β matrix in Fig. 4(b). As the Fe content futher increases to 1.5 and 2.0 wt%, only β grians can be found in the F15 and F20 alloys in Figs. 4(c) and 4(d). Although only β grians are found in both F15 and F20 alloys, the morphology of β grians exists significant diversity in those two alloys. Coarse β grians over 200 μm and some small globular β grians about 10 μm along boundaries of those coarse β grians can be found in the F15 alloy. Those small globular β grians along boundaries in the F15 alloys result from the dynamic recrystallization [31,32]. Tan [33,34] has also reported the similar result that the dynamic recrystallization presents in TiZr based alloys during hot deformation. However, most blocky β grains 7 / 18
appproximate 50 μm are observed in the F20 alloy. Those blocky β grains in the F20 alloy are the result of the further recrystalliazation and followed growth of the recrystallized β grains. The significant diversity in morphology of β grians in F15 and F20 alloys results from the variation of the β to α phase transition temperatures of those two alloys. Based on DSC results, the β to α phase transition temperature of the F20 alloys is 768 °C which is lower than that of the F15 alloys 790 °C. Previous literature [ 35 ] have been reported that enhanced deformation temperature can promote the recrystallization and grain growth. Although the F15 and F20 alloys were rolled at the same temperature, the lower phase transition temperature will induce higher temperature difference between rolling temperature and the phase transition temperature. Accordingly, grains in the F20 alloy should be easy to recrystallize and grow. TEM was used to further observe and analyze the microstructural charateristic of the F10 alloy. TEM bright field image and relative electronic diffraction pattern of the F10 alloy are showed in the Fig. 5. Bright field image in Fig. 5(a) shows that lots of lenticular α" martensites with thickness about several tens of nanometers exhibit in the β matrix. Electronic diffraction pattern in Fig. 5(b) also confirms that the F10 alloy is composed of α" martensite and retained β phase. Fig. 6 shows the tensile results of the examined alloys with various Fe contents. The stress-strain curves in the Fig. 6(a) indicate that the tensile behavior of low cost TiZrAlFe alloys obviously relies on the Fe content. The trend line of the elastic modulus E vs. Fe content in Fig. 6(b) shows that the E value of the F05 alloy is 104 GPa which is similar with the most of α +β type Ti based alloys [36]. As the Fe 8 / 18
content increases from 0.5 to 1.0 wt%, a rapid decrease in the E value is observed. The E value of the F10 alloy is only 66 GPa. As the Fe content further increases, conversely, the E value increases gradually. The F20 alloy has the E value of 78 GPa. The variations in strength and elongation of the examined alloys with Fe content are also discussed and results are showed in Fig. 6(c). The relation of yield strength and Fe content is nearly the same with that of elastic modulus. The lowest E value and yield strength of the F10 alloy are mainly because of precipitation of the α" martensite. Previous literatures [37-39] have shown that the α" martensite is a soft phase in Ti and TiZr based alloys comparing with the other conventional phases, such as α, α', ω and β. Thus, the α" martensite has lower elastic modulus and yield strength than other coventional phases. Consequently, the F10 alloy wiht some α" martensites has the lowest E value and yield strength. While the α" martensite disappears, the yield strength in the F15 and F20 alloys increases gradually. The continued increase in yield strength of the F20 alloy than the F15 alloy results from two major reasons. First is solution strengthening originating from more addition of Fe content. Second is the smaller grain size. Based on the micrographs in Figs. 4(c) and 4(d), the average β grain size of the F20 alloy is distinctly smaller than that of the F15 alloy. It is well know that the stength of metals and alloys increases with the decreasing of grain size. Thus, the yield strength of the F20 alloy is higher than that of the F15 alloy. Although yield stregnth of the F15 and F20 alloys increases gradually, it is still lower than that of the F05 alloy. The key factor is the precipitation of the α' martensite in the F05 alloy. Although the α' martensite in Ti alloys has not remarkably strengthening effect 9 / 18
by itself, the precipitation of the α' martensite obviously increases the density of grain boundary which strengthens the F05 alloy significantly [40,41].The tensile strength of the examined alloys decreases gradually from 1495 to 1212 MPa as the increasing of Fe content from 0.5 to 1.5 wt%. No rapid decrease in tensile strength exhibits at the alloy wiht Fe content of 1.0 wt% like elastic modulus and yield strength. As a soft phase in Ti and TiZr based alloys, the α" martensite has lower elastic modulus and yield strength. Concurrently, it has favourable ductility and high strain hardening [37,38]. Chuang et al [42] showed the similar result that the cast Ti–7.5Mo alloy with orthorhombic α" phase can be cold rolled down by an accumulated reduction of >80% in thickness. Stress-strain curve of the F10 alloy also shows the favourable ductility and high strain hardening. So, the tensile strength of the F10 does not decrease rapidly. As most of metals and alloys, the total elongation of the examined aloys exhibits an opposite trend to yield strength with the increasing of Fe content. The F05 alloy has lowest total elongation of 8.3%. A rapid increase in total elongation to 12.4% is observed at the F10 alloy. Then the total elongation decreases gradually to 8.7% as the increasing of Fe content to 2.0 wt%. The key factor of the diversity of ductility should be the plastic deformation mode of specimens with various Fe contents. The F05 alloy consists of hcp martensite and β phase with bcc structure, the F10 alloy consists of orthorhombic martensite and β phase, and the F15 and F20 alloys consist of only β phase. Deformation mode of F05 should be slip in hcp. In F10 alloy, stress induced martensite transformation will be occurred during tensile testing. At the same time, twinning should be occurred in F10 alloy during tensile testing. Deformation 10 / 18
mode of F15 and F20 alloys, only slip should be occurred [43]. 4． Conclusions A series of low cost TiZrAlFe alloys with ultra-high strength and favorable ducility are developed. The microstructue and mechanical properties varying with the Fe content are investigated. The main conclusions are as follows: (1) The β to α phase transition temperature of the TiZrAlFe alloys decreases from 836 to 768 °C with the increasing of Fe content from 0.5 to 2.0 wt%. (2) Phase constitution of the hot rolled TiZrAlFe alloys changes as α' + β → α" + β → β with the increasing of Fe content from 0.5 to 2.0 wt%. (3) Acicular α' martensite precipitates out of orignal β matrix in the examined alloy with Fe content of 0.5 wt%. As Fe content increases to 1.0 wt%, ultra-fine lenticular α" martensite with thickness of tens nanometers is observed. While the Fe content over 1.5 wt%, only blocky β grains can be found in the F15 and F20 alloys. Few recrystallized grains are observed in alloy with 1.5 wt% Fe content. Recrystallized β grains in the alloy with Fe content of 2.0 wt% further grow. (4) The examined alloys with Fe content of 0.5 wt% has 1495 MPa of tensile strength and 8.3% of total elongation. As the Fe content increases, the tensile strength decreased to 1212 MPa. All examined alloys with Fe content from 0.5 to 2.0 wt% have total elongation over 8%. Acknowledgements This work was supported by the SKPBRC (Grant No. 2013CB733000), NSFC (Grant Nos. 51271161/ 51401073), NSFH (Grant No. E2014402014) and PHSYTH 11 / 18
(Grant No. BJ2014017). References [1] V. Venkateswarlu, D. Tripathy, K. Rajagopal, K.T. Tharian, P.V. Venkitakrishnan, Failure analysis and optimization of thermo-mechanical process parameters of titanium alloy (Ti–6Al–4V) fasteners for aerospace applications, Case Stud. Eng. Fail. Anal., 2013, 1(2): 49–60. [2] J.W. Lu, Y.Q. Zhao, P. Ge, H.Z. Niu, Y.S. Zhang, W. Zhang, P.X. Zhang, Microstructure and mechanical properties of new high strength beta-titanium alloy Ti-1300, Mater. Sci. Eng. A, 2015, 621: 182–189. [3] S. Shekhar, R. Sarkar, S.K. Kar, A. Bhattacharjee, Effect of solution treatment and aging on microstructure and tensile properties of high strength β Titanium alloy, Ti–5Al–5V–5Mo–3Cr, Mater. Des., 2015, 66: 596–610. [4] C.L. Li, L.N. Zou, Y.Y. Fu, W.J. Ye, S.X. Hui, Effect of heat treatments on microstructure and property of a high strength/toughness Ti–8V–1.5Mo–2Fe– 3Al alloy, Mater. Sci. Eng. A, 2014, 616: 207–213. [5] M. Jayaprakash, D.H. Ping, Y. Yamabe-Mitarai, Enhanced yielding strength of near-α Ti–Al–Zr–Sn high temperature alloys, Mater. Sci. Eng. A, 2015, 625: 131–139. [6] W.J. Jia, W.D. Zeng, J.R. Liu, Y.G. Zhou, Q.J. Wang, Influence of thermal exposure on the tensile properties and microstructures of Ti60 Titanium alloy, Mater. Sci. Eng. A, 2011, 530: 511–518. [7] X. Wu, R. Sharman, J. Mei, W. Voice, Microstructure and properties of a laser fabricated burn-resistant Ti alloy, Mater. Des., 2004, 25(2): 103–109. [8] Y.Q. Zhao, H.L. Qu, K.Y. Zhu, H. Wu, L. Zhou, Oxidation behavior of a burn resistant highly stabilized β Titanium alloy, Mater. Sci. Eng. A, 2001, 316(1–2): 211–216. [9] Y.Q. Zhao, J.F. Wei, Z.J. Gao, Y.L. Li, H. Wu, C.L. Liu, L. Feng, H. Chang, Titanium alloys: current status of application and low cost manufacturing technologies, Mater. Rev., 2003, 17(4): 5–7. 12 / 18
[10] D. V. Louzguine, H. Kato, A. Inoue, High strength and ductile binary Ti–Fe composite alloy, J. Alloys Compd., 2004, 384(1–2): L1–L3. [11] B. Liu, Y. Liu, C.Z. Qiu, C.X. Zhou, J.B. Li, H.Z. Li, Y.H. He, Design of Low-Cost Titanium aluminide intermetallics, J. Alloys Compd., 2015, doi:10.1016/j.jallcom.2015.03.239. [12] B. Gunawarman, M. Niinomi, T. Akahori, T. Souma, M. Ikeda, H. Toda, Mechanical properties and microstructures of low cost β Titanium alloys for healthcare applications, Mater. Sci. Eng. C, 2005, 25(3): 304–311. [13] M. Hagiwara, S.J. Kim, S. Emura, Blended elemental P/M synthesis of Ti-6Al-1.7Fe-0.1Si alloy with improved high cycle fatigue strength, Scripta Mater., 1998, 39(9): 1185–1190. [14] S.X. Liang, L.X. Yin, H.W. Che, R. Jing, Y.K. Zhou, M.Z. Ma, R.P. Liu, Effects of Al content on structure and mechanical properties of hot-rolled ZrTiAlV alloys, Mater. Des., 2013, 52(0): 246–250. [15] S.X. Liang, M.Z. Ma, R. Jing, X.Y. Zhang, R.P. Liu, Microstructure and mechanical properties of hot-rolled ZrTiAlV alloys, Mater. Sci. Eng. A, 2012, 532(0): 1–5. [16] R. Jing, S.X. Liang, C.Y. Liu, M.Z. Ma, X.Y. Zhang, R.P. Liu, Structure and mechanical properties of Ti–6Al–4V alloy after Zirconium addition, Mater. Sci. Eng. A, 2012, 552: 295–300. [17] X.J. Jiang, R. Jing, C.Y. Liu, M.Z. Ma, R.P. Liu, Structure and mechanical properties of TiZr binary alloy after Al addition, Mater. Sci. Eng. A, 2013, 586: 301–305. [18] R. Jing, S.X. Liang, C.Y. Liu, M.Z. Ma, R.P. Liu, Aging effects on the microstructures and mechanical properties of the Ti–20Zr–6.5Al–4V alloy, Mater. Sci. Eng. A, 2013, 559: 474–479. [19] S.X. Liang, M.Z. Ma, R. Jing, Y.K. Zhou, Q. Jing, R.P. Liu, Preparation of the ZrTiAlV alloy with ultra-high strength and good ductility, Mater. Sci. Eng. A, 2012, 539: 42–47. 13 / 18
[20] Y. Cui, Y. Li, K. Luo, H.B. Xu, Microstructure and shape memory effect of Ti– 20Zr–10Nb alloy, Mater. Sci. Eng. A, 2010, 527(3): 652–656. [21] J. Meng, X.T. Yang, J.H. Zhang, W.S. Yang, D.Z. Guo, Z.J. Hu, Y.G. Zhao, S.J. Hou, C. Luo, Research of tizrv pumping coatings on the inner walls of vacuum chamber, Phys. Procedia, 2012, 32: 865–868. [22] Factsage, Fe-Ti phase diagram, SGTE 2007 alloy database, http://www.crct.polymtl.ca/FACT/phase_diagram.php?file=Fe-Ti.jpg&dir=SGT E2007. [23] Factsage, Fe-Zr phase diagram, SGTE 2007 alloy database, http://www.crct.polymtl.ca/FACT/phase_diagram.php?file=Fe-Zr.jpg&dir=SGT E2007. [24] Y.J. Fan, J.M. Cao, H.B. Yang, Z.H. Chen, L. Li, Effect of Fe content on mechanical properties of Ti-6Al-4V alloy, Heat Treat. Met., 2013, 28(3): 21–23. [25] C.Z. Qiu, Y. Liu, L. Huang, W. Zhang, B. Liu, B. Lu, Effect of Fe and Mo additions on microstructure and mechanical properties of TiAl intermetallics, T. Nonfer. Metal. Soc., 2012, 22(3): 521–527. [26] J. Syarif, T.N. Rohmannudin, M.Z. Omar, Z. Sajuri, S. Harjanto, Stability of the beta phase in Ti–Mo–Cr alloy fabricated by powder metallurgy, J. Min. Metall. Sect. B-Metall., 2013, 49: 285–292. [27] L.W. Ma, H.S. Cheng, C.Y. Chung, B. Yuan, Super elastic behavior and microstructure of Ti19Nb9Zr1Mo (at. %) alloy, Mater. Lett., 2013, 109: 172– 174. [28] Wikipedia, Titanium, http://en.wikipedia.org/wiki/Titanium, 2015-4-6. [29] Wikipedia, Zirconium, http://en.wikipedia.org/wiki/Zirconium, 2015-4-10. [30] Wikipedia, Iron, http://en.wikipedia.org/wiki/Iron, 2015-4-7. [31] L. Cheng, H. Chang, B. Tang, H.C. Kou, J.S. Li, Deformation and dynamic recrystallization behavior of a high Nb containing TiAl alloy, J. Alloys Compd., 2013, 552: 363–369. [32] T. Sakai, A. Belyakov, R. Kaibyshev, H. Miura, J.J. Jonas, Dynamic and 14 / 18
post-dynamic recrystallization under hot, cold and severe plastic deformation conditions, Prog. Mater. Sci., 2014, 60: 130–207. [33] Y.B. Tan, L.H. Yang, C. Tian, R.P. Liu, X.Y. Zhang, W.C. Liu, Hot deformation behavior of ZrTiAlV alloy with a coarse grain structure in the β phase field, Mater. Sci. Eng. A, 2013, 577: 218–224. [34] Y.B. Tan, J.L. Duan, L.H. Yang, W.C. Liu, J.W. Zhang, R.P. Liu, Hot deformation behavior of Ti–20Zr–6.5Al–4V alloy in the α+β and single β phase field, Mater. Sci. Eng. A, 2014, 609: 226–234. [35] O. Beltran, K. Huang, R.E. Logé, A mean field model of dynamic and post-dynamic recrystallization predicting kinetics, grain size and flow stress, Comput. Mater. Sci., 2015, 102: 293–303. [36] J.H. Luan, Z.B. Jiao, L. Heatherly, E.P. George, G. Chen, C.T. Liu, Effects of boron on the fracture behavior and ductility of cast Ti–6Al–4V alloys, Scripta Mater., 2015, 100: 90–93. [37] X.J. Jiang, R. Jing, M.Z. Ma, R.P. Liu, The orthorhombic α" martensite transformation during water quenching and its influence on mechanical properties of Ti-41Zr-7.3Al alloy, Intermetallics, 2014, 52: 32–35. [38] S.X. Liang, L.X. Yin, X.Y. Liu, X.L. Zhang, M.Z. Ma, R.P. Liu, C.L. Tan, Microstructure evolution and mechanical properties response of a TZAV alloy during combined thermomechanical treatments, Mater. Sci. Eng. A, 2014, 619: 87–94. [39] M. Premkumar, A.K. Singh, Deformation behavior of an ordered B2 phase in Ti–25Al–25Zr alloy. Intermetallics, 2010, 18: 199–201. [40] S.X. Liang, L.X. Yin, R.J. Jiang, X.Y. Zhang, M.Z. Ma, R.P. Liu, Strengthening mechanism of two-phase titanium alloys with basketweave microstructure, J. Alloys Compd., 2014, 603: 42–47. [41] A. Dehghan-Manshadi, R.J. Dippenaar, Development of α-phase morphologies during low temperature isothermal heat treatment of a Ti–5Al–5Mo–5V–3Cr alloy, Mater. Sci. Eng. A, 2011, 528: 1833–1839. 15 / 18
[42] C.C. Chung, S.W. Wang, Y.C. Chen, C.P. Ju, J.H.C. Lin, Effect of cold rolling on structure and tensile properties of cast Ti–7.5Mo alloy, Mater. Sci. Eng. A, 2015, 631: 52–66. [43] S. Hanada, T. Yoshio and O. Izumi, Plastic deformation mode of retained β phase in β-eutectoid Ti-Fe alloys, J. Mater. Sci., 1986, 21(3): 866–870.
16 / 18
Figure caption Fig. 1 Schematic diagram of tensile specimens Fig. 2 DSC curves of the examined alloys with various Fe contents Fig. 3 XRD patterns of the examined alloys with various Fe contents Fig. 4 OM micrographs of the examined alloys (a) F05, (b) F10, (c) F15, and (d) F20 Fig. 5 TEM results of the F10 alloy (a) bright field image and (b) electronic diffraction pattern Fig. 6 Tensile results of the examined alloys with various Fe contents (a) stress-strain curves, (b) relation between elastic modulus E and Fe content, and (c) trend lines of strength and elongation vs. Fe content, E, YS and TS is the short form of elastic modulus, yield strength and tensile strength, respectively
17 / 18
Table caption Table 1 Actual alloy compositions of the examined TiZrAlFe alloys, wt% Alloys
Ti
Zr
Al
Fe
F05
47.51
47.51
4.47
0.51
F10
47.15
47.39
4.47
0.99
F15
47.30
47.99
4.56
1.51
F20
46.76
46.86
4.41
1.97
Table 2 effect of Fe content on the phase structure of the examined alloys Lattice constant, nm Alloys
Phases composition a α' (hcp)
0.3118(3)
β (bcc)
0.3393(4)
α" (orthorhombic)
0.3099(9)
β
0.3389(5)
F15
β
0.3385(3)
F20
β
0.3376(8)
b
c 0.4825(6)
F05
F10
18 / 18
0.4720(9)
0.5154(1)
Figure 1
Figure 2
Figure 3
Figure 4a
Figure 4b
Figure 4c
Figure 4d
Figure 5a
Figure 5b
Figure 6a
Figure 6b
Figure 6c
PII: DOI: Reference:
S0921-5093(15)30012-5 http://dx.doi.org/10.1016/j.msea.2015.05.067 MSA32395
To appear in: Materials Science & Engineering A Received date: 15 April 2015 Revised date: 18 May 2015 Accepted date: 21 May 2015 Cite this article as: S.X. Liang, L.X. Yin, L.Y. Zheng, M.Z. Ma and R.P. Liu, Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable d u c t i l i t y , Materials Science & Engineering A, http://dx.doi.org/10.1016/j.msea.2015.05.067 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Preparation of low cost TiZrAlFe alloy with ultra-high strength and favorable ductility S.X. Liang a,*, L.X. Yin a, L.Y. Zheng a, M.Z. Ma b, R.P. Liu b a
College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, Hebei, China
b
State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
Abstract Cost reducing has always been a very important future development for Ti alloys. A new series of low cost TiZrAlFe alloys with ultra-high strength and favorable ductility are developed in this work. The microstructure and mechanical properties of the new series of low cost TiZr based alloys with Fe content from 0.5 to 2.0 wt% are investigated. As Fe content increases from 0.5 to 2.0 wt%, the β to α phase transition temperature decreases from 836 to 768 °C, and the phase constitution of the examined alloys changes from α' + β to α" + β and finally whole β phase. That acicular α' martensite precipitating out of β matrix is the microstructural feature of the developed low cost alloy with Fe content of 0.5 wt%. As the Fe content increases to 1.0 wt%, the microstructural characteristic is some ultra-fine lenticular α" martensites with tens nanometers thickness enchased in β matrix. As the Fe content further increases to 1.5 wt%, the β grains generate recrystallization. Microstructural features of β grains further recrystallization and growth exhibit in the examined alloy with Fe content of 2.0 wt%. Tensile results show that the new series of low cost alloys have 1 / 18
ultra-high strength and favorable ductility. The strength of the examined alloys changes from 1495 to 1212 MPa as the increasing of Fe content from 0.5 to 2.0 wt%. Meanwhile the total elongation ranges from 8.3% to 12.4%. The strengthening mechanism of the developed low cost TiZr based alloys is also discussed. The current finding not only presents an excellent alloy with superior combination of strength and ductility but promotes the development and application of low cost Ti alloys. Keywords: Ti alloys; Low cost; Microstructure; Mechanical properties
*Corresponding author address: College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, China E-mail: [email protected] Tel: 0086-310-8577971
2 / 18
1． Introduction Titanium (Ti) and Ti alloys with numerous favorable properties such as low density, high specific strength, corrosion resistant, good mid-temperature properties, nonmagnetic, and so on, are important structural materials and have been widely used in national defense, aerospace, marine, motorsport et al fields [1]. Series high performance Ti alloys have been developed in recent decades such as ultra-high strength Ti alloys (the tensile strength over 1250 MPa) [2-4], high temperature Ti alloys [5,6] and burn-resistant Ti alloys [7,8]. However, expensive cost of Ti alloys severely limits its development. The actural dosage is much lower than that of conventional steel and aluminium alloys. Practices and researches showed that cost of expensive raw materials accounts for approximately 40% of the total cost of Ti alloys [9]. Therefore, replacement of expensive raw materials such as V, Nb, Mo with cheap raw materials like Fe, Cr, Mn et al is an effective way to reduce the total cost of Ti alloys [10-12]. Among them, the 62S
(Ti-6Al-1.7Fe-0.1Si)
[ 13 ],
TFC
(Ti-4.3Fe-7.1Cr)
and
TFCA
(Ti-4.3Fe-7.1Cr-3.0Al) [12] et al are the representative low cost Ti alloys with high performance. For now, research on low cost Ti alloys with high strength and toughness is still the important content and the development direction of Ti alloys. Attributing to the similar physicochemical properties between elements of Ti and Zr, recently developed TiZr based alloys exhibit favorable mechanical properties [14-17]. The representative Ti–20Zr–6.5Al–4V [18] and Ti–30Zr–5Al–3V [19] alloys have tensile strength over 1600 MPa, and specific strength over 340 MPa/(g/cm 3). 3 / 18
Accordingly, the TiZr based series alloys show widely applied prospect as structure materials. However, almost all of current TiZr based alloys with high performance contain expensive raw materials such as V, Nb et al [20,21]. Replacement of those expensive raw materials with low cost raw materials without loss of its strength and toughness is also important to reduce cost and promote industrial applications of TiZr based alloys. The current study aims to develop a new series of low cost TiZr based alloys by replacing of expensive raw materials with cheap Fe element. The effects of Fe content on the microstructure and mechanical properties of the TiZr based alloys are also discussed. This study will facilitate the development and actual application of low cost Ti and TiZr based alloys. 2． Experimental procedure Sponge Ti (99.7 wt%), sponge Zr (Zr + Hf ≥ 99.5 wt%), industrially pure Al (99.5 wt%), and Fe (99.9 wt%) were used to prepared the TiZrAlFe series alloys. Raw materials were melted using high-vacuum non-consumable are melting furnace in a Ti-gettered argon atmosphere. To guarantee the uniformity, each ingot was remelted at least four times. Actual alloy compositions are showed in table 1. Ingots were heated to 850 °C and held for 10 min, and then rolled into plated samples with a thickness of 4 mm. The plated samples were water quenched immediately after rolling. Hot rolled specimens were removed about 1 mm on each rolled surfaces for followed tests and analysis. Differential scanning calorimetry (DSC) was used to test the phase transition 4 / 18
temperatures using heating velocity 10 °C/min adopting the standard of ASTM: F2004–05(2010). The DSC samples were full annealed at 850 °C for 2h and cooled inside the furnace to 300 °C then air cooled to room temperature. Phase structure of hot rolled specimens was determined by X-ray diffraction (XRD) using copper Kα X-radiation (ASTM: D5380-93(2014)). Microstructure was observed through transmission electron microscopy (TEM) and Olympus DSX500 type optical microscopy
(OM).
TEM
analytic
specimens
were
prepared
by
twin-jet
electrochemical polishing in a solution of 10% perchloric acid and 90% methanol at 13 V and -30 °C. Tensile samples were machined from hot-rolled plates after removing 1 mm thick portions from both sides of the rolled surface. The size of tensile samples is shown in Fig. 1. Uniaxial tensile tests (ASTM: E8/E8M–11) were performed on an INSTRON 5982 testing machine at a strain rate of 5×10-4 s-1. The strain during the entire testing process was monitored using an extensometer with a 12.5 mm gauge length. 3． Results and discussion Fig. 2 shows the DSC curves near phase transition of the examined alloys with various Fe contents. The onset and end transition temperatures of the α phase into β phase for F05 alloy are approximately 764 °C and 836 °C, respectively. As the Fe content increases, the end transition temperature of the α phase into β phase of the examined alloys decreases gradually. While the Fe content reaches 2 wt%, the end transition temperature of the α phase into β phase of the F20 alloy decreases to 768 °C. According to the Ti-Fe [22] and Zr-Fe [23] binary phase diagrams and 5 / 18
previous results [24,25] about effects of Fe on the phase stability of Ti and/or Zr alloys, it is easy to conclude that Fe is an β-stabilizer for Ti and Zr alloys. Thus, the end transition temperature of α phase into β phase of the examined alloys decreases with the increasing of Fe content. However, the trend of onset transition temperature changed with Fe content is not consistent completely with that of end transition temperature. The onset transition temperature also decreases from 764 to 716 °C with the increasing of Fe content from 0.5 to 1.0 wt%. Nevertheless, the onset transition temperature is kept near 720 °C while the Fe content further increases from 1.0 to 2.0 wt%. Fig. 3 shows the XRD patterns of the low cost TiZrAlFe series alloys with different Fe contents. The phase compoition of the examined low cost TiZr based alloys is greatly dependent on the Fe content. The F05 alloy is composed of α' martensite and retained β phase. As the Fe content increases to 1.0 wt%, the F10 alloy consists of α" martensite and retained β phase.As the Fe content further increases to or over 1.5 wt%, the phase constitution of the examined alloys is wholy retained β phase. The phase constitution of the examined alloys with various Fe contents is showed in the table 2. Previous results [26,27] showed that the phase constitution of water quenched Ti and/or Zr based alloys will change as α' → α" / ω → β with the increasing of β-stabilizer. Based on the DSC results, the stability of β phase in the examined alloys increases with the increasing of Fe content. Consequently, the phase constitution of the examined alloys also varies with the increasing of Fe content. The lattice constants of the constituent phases in the examined alloys are also obtained 6 / 18
according to the XRD patterns and results are also showed in table 2. The lattice constant a of the α' martensite in the F05 alloy is appproximate 0.31183 nm which is higher than that of the TiZr based alloys in previous literature [16]. The key factor of that higher value is the more addition of Zr element with larger atomic radius R. From the table 2, it is easy to find that the lattice constant a of the β phase slightly decreases with the increasing of Fe content. The slightly decreasing results from the replacement of larger elements of Ti (R = 147 pm [28]) and Zr (R = 160 pm [29]) with smaller Fe (R = 126 pm [30]) element. Fig. 4 shows the OM micrographs of the examined alloys with various Fe contents. Microstructure of the examined alloys is remarkably dependent on the addition of Fe content. The microstructural feature of the F05 alloy is that acicular α' martensites presipitate out of the orignal β matrix in Fig. 4(a). As the Fe content increases to 1.0 wt%, the microstructure characteristic of the F10 alloy is featured by very fine dot or rodlet α" grains in β matrix in Fig. 4(b). As the Fe content futher increases to 1.5 and 2.0 wt%, only β grians can be found in the F15 and F20 alloys in Figs. 4(c) and 4(d). Although only β grians are found in both F15 and F20 alloys, the morphology of β grians exists significant diversity in those two alloys. Coarse β grians over 200 μm and some small globular β grians about 10 μm along boundaries of those coarse β grians can be found in the F15 alloy. Those small globular β grians along boundaries in the F15 alloys result from the dynamic recrystallization [31,32]. Tan [33,34] has also reported the similar result that the dynamic recrystallization presents in TiZr based alloys during hot deformation. However, most blocky β grains 7 / 18
appproximate 50 μm are observed in the F20 alloy. Those blocky β grains in the F20 alloy are the result of the further recrystalliazation and followed growth of the recrystallized β grains. The significant diversity in morphology of β grians in F15 and F20 alloys results from the variation of the β to α phase transition temperatures of those two alloys. Based on DSC results, the β to α phase transition temperature of the F20 alloys is 768 °C which is lower than that of the F15 alloys 790 °C. Previous literature [ 35 ] have been reported that enhanced deformation temperature can promote the recrystallization and grain growth. Although the F15 and F20 alloys were rolled at the same temperature, the lower phase transition temperature will induce higher temperature difference between rolling temperature and the phase transition temperature. Accordingly, grains in the F20 alloy should be easy to recrystallize and grow. TEM was used to further observe and analyze the microstructural charateristic of the F10 alloy. TEM bright field image and relative electronic diffraction pattern of the F10 alloy are showed in the Fig. 5. Bright field image in Fig. 5(a) shows that lots of lenticular α" martensites with thickness about several tens of nanometers exhibit in the β matrix. Electronic diffraction pattern in Fig. 5(b) also confirms that the F10 alloy is composed of α" martensite and retained β phase. Fig. 6 shows the tensile results of the examined alloys with various Fe contents. The stress-strain curves in the Fig. 6(a) indicate that the tensile behavior of low cost TiZrAlFe alloys obviously relies on the Fe content. The trend line of the elastic modulus E vs. Fe content in Fig. 6(b) shows that the E value of the F05 alloy is 104 GPa which is similar with the most of α +β type Ti based alloys [36]. As the Fe 8 / 18
content increases from 0.5 to 1.0 wt%, a rapid decrease in the E value is observed. The E value of the F10 alloy is only 66 GPa. As the Fe content further increases, conversely, the E value increases gradually. The F20 alloy has the E value of 78 GPa. The variations in strength and elongation of the examined alloys with Fe content are also discussed and results are showed in Fig. 6(c). The relation of yield strength and Fe content is nearly the same with that of elastic modulus. The lowest E value and yield strength of the F10 alloy are mainly because of precipitation of the α" martensite. Previous literatures [37-39] have shown that the α" martensite is a soft phase in Ti and TiZr based alloys comparing with the other conventional phases, such as α, α', ω and β. Thus, the α" martensite has lower elastic modulus and yield strength than other coventional phases. Consequently, the F10 alloy wiht some α" martensites has the lowest E value and yield strength. While the α" martensite disappears, the yield strength in the F15 and F20 alloys increases gradually. The continued increase in yield strength of the F20 alloy than the F15 alloy results from two major reasons. First is solution strengthening originating from more addition of Fe content. Second is the smaller grain size. Based on the micrographs in Figs. 4(c) and 4(d), the average β grain size of the F20 alloy is distinctly smaller than that of the F15 alloy. It is well know that the stength of metals and alloys increases with the decreasing of grain size. Thus, the yield strength of the F20 alloy is higher than that of the F15 alloy. Although yield stregnth of the F15 and F20 alloys increases gradually, it is still lower than that of the F05 alloy. The key factor is the precipitation of the α' martensite in the F05 alloy. Although the α' martensite in Ti alloys has not remarkably strengthening effect 9 / 18
by itself, the precipitation of the α' martensite obviously increases the density of grain boundary which strengthens the F05 alloy significantly [40,41].The tensile strength of the examined alloys decreases gradually from 1495 to 1212 MPa as the increasing of Fe content from 0.5 to 1.5 wt%. No rapid decrease in tensile strength exhibits at the alloy wiht Fe content of 1.0 wt% like elastic modulus and yield strength. As a soft phase in Ti and TiZr based alloys, the α" martensite has lower elastic modulus and yield strength. Concurrently, it has favourable ductility and high strain hardening [37,38]. Chuang et al [42] showed the similar result that the cast Ti–7.5Mo alloy with orthorhombic α" phase can be cold rolled down by an accumulated reduction of >80% in thickness. Stress-strain curve of the F10 alloy also shows the favourable ductility and high strain hardening. So, the tensile strength of the F10 does not decrease rapidly. As most of metals and alloys, the total elongation of the examined aloys exhibits an opposite trend to yield strength with the increasing of Fe content. The F05 alloy has lowest total elongation of 8.3%. A rapid increase in total elongation to 12.4% is observed at the F10 alloy. Then the total elongation decreases gradually to 8.7% as the increasing of Fe content to 2.0 wt%. The key factor of the diversity of ductility should be the plastic deformation mode of specimens with various Fe contents. The F05 alloy consists of hcp martensite and β phase with bcc structure, the F10 alloy consists of orthorhombic martensite and β phase, and the F15 and F20 alloys consist of only β phase. Deformation mode of F05 should be slip in hcp. In F10 alloy, stress induced martensite transformation will be occurred during tensile testing. At the same time, twinning should be occurred in F10 alloy during tensile testing. Deformation 10 / 18
mode of F15 and F20 alloys, only slip should be occurred [43]. 4． Conclusions A series of low cost TiZrAlFe alloys with ultra-high strength and favorable ducility are developed. The microstructue and mechanical properties varying with the Fe content are investigated. The main conclusions are as follows: (1) The β to α phase transition temperature of the TiZrAlFe alloys decreases from 836 to 768 °C with the increasing of Fe content from 0.5 to 2.0 wt%. (2) Phase constitution of the hot rolled TiZrAlFe alloys changes as α' + β → α" + β → β with the increasing of Fe content from 0.5 to 2.0 wt%. (3) Acicular α' martensite precipitates out of orignal β matrix in the examined alloy with Fe content of 0.5 wt%. As Fe content increases to 1.0 wt%, ultra-fine lenticular α" martensite with thickness of tens nanometers is observed. While the Fe content over 1.5 wt%, only blocky β grains can be found in the F15 and F20 alloys. Few recrystallized grains are observed in alloy with 1.5 wt% Fe content. Recrystallized β grains in the alloy with Fe content of 2.0 wt% further grow. (4) The examined alloys with Fe content of 0.5 wt% has 1495 MPa of tensile strength and 8.3% of total elongation. As the Fe content increases, the tensile strength decreased to 1212 MPa. All examined alloys with Fe content from 0.5 to 2.0 wt% have total elongation over 8%. Acknowledgements This work was supported by the SKPBRC (Grant No. 2013CB733000), NSFC (Grant Nos. 51271161/ 51401073), NSFH (Grant No. E2014402014) and PHSYTH 11 / 18
(Grant No. BJ2014017). References [1] V. Venkateswarlu, D. Tripathy, K. Rajagopal, K.T. Tharian, P.V. Venkitakrishnan, Failure analysis and optimization of thermo-mechanical process parameters of titanium alloy (Ti–6Al–4V) fasteners for aerospace applications, Case Stud. Eng. Fail. Anal., 2013, 1(2): 49–60. [2] J.W. Lu, Y.Q. Zhao, P. Ge, H.Z. Niu, Y.S. Zhang, W. Zhang, P.X. Zhang, Microstructure and mechanical properties of new high strength beta-titanium alloy Ti-1300, Mater. Sci. Eng. A, 2015, 621: 182–189. [3] S. Shekhar, R. Sarkar, S.K. Kar, A. Bhattacharjee, Effect of solution treatment and aging on microstructure and tensile properties of high strength β Titanium alloy, Ti–5Al–5V–5Mo–3Cr, Mater. Des., 2015, 66: 596–610. [4] C.L. Li, L.N. Zou, Y.Y. Fu, W.J. Ye, S.X. Hui, Effect of heat treatments on microstructure and property of a high strength/toughness Ti–8V–1.5Mo–2Fe– 3Al alloy, Mater. Sci. Eng. A, 2014, 616: 207–213. [5] M. Jayaprakash, D.H. Ping, Y. Yamabe-Mitarai, Enhanced yielding strength of near-α Ti–Al–Zr–Sn high temperature alloys, Mater. Sci. Eng. A, 2015, 625: 131–139. [6] W.J. Jia, W.D. Zeng, J.R. Liu, Y.G. Zhou, Q.J. Wang, Influence of thermal exposure on the tensile properties and microstructures of Ti60 Titanium alloy, Mater. Sci. Eng. A, 2011, 530: 511–518. [7] X. Wu, R. Sharman, J. Mei, W. Voice, Microstructure and properties of a laser fabricated burn-resistant Ti alloy, Mater. Des., 2004, 25(2): 103–109. [8] Y.Q. Zhao, H.L. Qu, K.Y. Zhu, H. Wu, L. Zhou, Oxidation behavior of a burn resistant highly stabilized β Titanium alloy, Mater. Sci. Eng. A, 2001, 316(1–2): 211–216. [9] Y.Q. Zhao, J.F. Wei, Z.J. Gao, Y.L. Li, H. Wu, C.L. Liu, L. Feng, H. Chang, Titanium alloys: current status of application and low cost manufacturing technologies, Mater. Rev., 2003, 17(4): 5–7. 12 / 18
[10] D. V. Louzguine, H. Kato, A. Inoue, High strength and ductile binary Ti–Fe composite alloy, J. Alloys Compd., 2004, 384(1–2): L1–L3. [11] B. Liu, Y. Liu, C.Z. Qiu, C.X. Zhou, J.B. Li, H.Z. Li, Y.H. He, Design of Low-Cost Titanium aluminide intermetallics, J. Alloys Compd., 2015, doi:10.1016/j.jallcom.2015.03.239. [12] B. Gunawarman, M. Niinomi, T. Akahori, T. Souma, M. Ikeda, H. Toda, Mechanical properties and microstructures of low cost β Titanium alloys for healthcare applications, Mater. Sci. Eng. C, 2005, 25(3): 304–311. [13] M. Hagiwara, S.J. Kim, S. Emura, Blended elemental P/M synthesis of Ti-6Al-1.7Fe-0.1Si alloy with improved high cycle fatigue strength, Scripta Mater., 1998, 39(9): 1185–1190. [14] S.X. Liang, L.X. Yin, H.W. Che, R. Jing, Y.K. Zhou, M.Z. Ma, R.P. Liu, Effects of Al content on structure and mechanical properties of hot-rolled ZrTiAlV alloys, Mater. Des., 2013, 52(0): 246–250. [15] S.X. Liang, M.Z. Ma, R. Jing, X.Y. Zhang, R.P. Liu, Microstructure and mechanical properties of hot-rolled ZrTiAlV alloys, Mater. Sci. Eng. A, 2012, 532(0): 1–5. [16] R. Jing, S.X. Liang, C.Y. Liu, M.Z. Ma, X.Y. Zhang, R.P. Liu, Structure and mechanical properties of Ti–6Al–4V alloy after Zirconium addition, Mater. Sci. Eng. A, 2012, 552: 295–300. [17] X.J. Jiang, R. Jing, C.Y. Liu, M.Z. Ma, R.P. Liu, Structure and mechanical properties of TiZr binary alloy after Al addition, Mater. Sci. Eng. A, 2013, 586: 301–305. [18] R. Jing, S.X. Liang, C.Y. Liu, M.Z. Ma, R.P. Liu, Aging effects on the microstructures and mechanical properties of the Ti–20Zr–6.5Al–4V alloy, Mater. Sci. Eng. A, 2013, 559: 474–479. [19] S.X. Liang, M.Z. Ma, R. Jing, Y.K. Zhou, Q. Jing, R.P. Liu, Preparation of the ZrTiAlV alloy with ultra-high strength and good ductility, Mater. Sci. Eng. A, 2012, 539: 42–47. 13 / 18
[20] Y. Cui, Y. Li, K. Luo, H.B. Xu, Microstructure and shape memory effect of Ti– 20Zr–10Nb alloy, Mater. Sci. Eng. A, 2010, 527(3): 652–656. [21] J. Meng, X.T. Yang, J.H. Zhang, W.S. Yang, D.Z. Guo, Z.J. Hu, Y.G. Zhao, S.J. Hou, C. Luo, Research of tizrv pumping coatings on the inner walls of vacuum chamber, Phys. Procedia, 2012, 32: 865–868. [22] Factsage, Fe-Ti phase diagram, SGTE 2007 alloy database, http://www.crct.polymtl.ca/FACT/phase_diagram.php?file=Fe-Ti.jpg&dir=SGT E2007. [23] Factsage, Fe-Zr phase diagram, SGTE 2007 alloy database, http://www.crct.polymtl.ca/FACT/phase_diagram.php?file=Fe-Zr.jpg&dir=SGT E2007. [24] Y.J. Fan, J.M. Cao, H.B. Yang, Z.H. Chen, L. Li, Effect of Fe content on mechanical properties of Ti-6Al-4V alloy, Heat Treat. Met., 2013, 28(3): 21–23. [25] C.Z. Qiu, Y. Liu, L. Huang, W. Zhang, B. Liu, B. Lu, Effect of Fe and Mo additions on microstructure and mechanical properties of TiAl intermetallics, T. Nonfer. Metal. Soc., 2012, 22(3): 521–527. [26] J. Syarif, T.N. Rohmannudin, M.Z. Omar, Z. Sajuri, S. Harjanto, Stability of the beta phase in Ti–Mo–Cr alloy fabricated by powder metallurgy, J. Min. Metall. Sect. B-Metall., 2013, 49: 285–292. [27] L.W. Ma, H.S. Cheng, C.Y. Chung, B. Yuan, Super elastic behavior and microstructure of Ti19Nb9Zr1Mo (at. %) alloy, Mater. Lett., 2013, 109: 172– 174. [28] Wikipedia, Titanium, http://en.wikipedia.org/wiki/Titanium, 2015-4-6. [29] Wikipedia, Zirconium, http://en.wikipedia.org/wiki/Zirconium, 2015-4-10. [30] Wikipedia, Iron, http://en.wikipedia.org/wiki/Iron, 2015-4-7. [31] L. Cheng, H. Chang, B. Tang, H.C. Kou, J.S. Li, Deformation and dynamic recrystallization behavior of a high Nb containing TiAl alloy, J. Alloys Compd., 2013, 552: 363–369. [32] T. Sakai, A. Belyakov, R. Kaibyshev, H. Miura, J.J. Jonas, Dynamic and 14 / 18
post-dynamic recrystallization under hot, cold and severe plastic deformation conditions, Prog. Mater. Sci., 2014, 60: 130–207. [33] Y.B. Tan, L.H. Yang, C. Tian, R.P. Liu, X.Y. Zhang, W.C. Liu, Hot deformation behavior of ZrTiAlV alloy with a coarse grain structure in the β phase field, Mater. Sci. Eng. A, 2013, 577: 218–224. [34] Y.B. Tan, J.L. Duan, L.H. Yang, W.C. Liu, J.W. Zhang, R.P. Liu, Hot deformation behavior of Ti–20Zr–6.5Al–4V alloy in the α+β and single β phase field, Mater. Sci. Eng. A, 2014, 609: 226–234. [35] O. Beltran, K. Huang, R.E. Logé, A mean field model of dynamic and post-dynamic recrystallization predicting kinetics, grain size and flow stress, Comput. Mater. Sci., 2015, 102: 293–303. [36] J.H. Luan, Z.B. Jiao, L. Heatherly, E.P. George, G. Chen, C.T. Liu, Effects of boron on the fracture behavior and ductility of cast Ti–6Al–4V alloys, Scripta Mater., 2015, 100: 90–93. [37] X.J. Jiang, R. Jing, M.Z. Ma, R.P. Liu, The orthorhombic α" martensite transformation during water quenching and its influence on mechanical properties of Ti-41Zr-7.3Al alloy, Intermetallics, 2014, 52: 32–35. [38] S.X. Liang, L.X. Yin, X.Y. Liu, X.L. Zhang, M.Z. Ma, R.P. Liu, C.L. Tan, Microstructure evolution and mechanical properties response of a TZAV alloy during combined thermomechanical treatments, Mater. Sci. Eng. A, 2014, 619: 87–94. [39] M. Premkumar, A.K. Singh, Deformation behavior of an ordered B2 phase in Ti–25Al–25Zr alloy. Intermetallics, 2010, 18: 199–201. [40] S.X. Liang, L.X. Yin, R.J. Jiang, X.Y. Zhang, M.Z. Ma, R.P. Liu, Strengthening mechanism of two-phase titanium alloys with basketweave microstructure, J. Alloys Compd., 2014, 603: 42–47. [41] A. Dehghan-Manshadi, R.J. Dippenaar, Development of α-phase morphologies during low temperature isothermal heat treatment of a Ti–5Al–5Mo–5V–3Cr alloy, Mater. Sci. Eng. A, 2011, 528: 1833–1839. 15 / 18
[42] C.C. Chung, S.W. Wang, Y.C. Chen, C.P. Ju, J.H.C. Lin, Effect of cold rolling on structure and tensile properties of cast Ti–7.5Mo alloy, Mater. Sci. Eng. A, 2015, 631: 52–66. [43] S. Hanada, T. Yoshio and O. Izumi, Plastic deformation mode of retained β phase in β-eutectoid Ti-Fe alloys, J. Mater. Sci., 1986, 21(3): 866–870.
16 / 18
Figure caption Fig. 1 Schematic diagram of tensile specimens Fig. 2 DSC curves of the examined alloys with various Fe contents Fig. 3 XRD patterns of the examined alloys with various Fe contents Fig. 4 OM micrographs of the examined alloys (a) F05, (b) F10, (c) F15, and (d) F20 Fig. 5 TEM results of the F10 alloy (a) bright field image and (b) electronic diffraction pattern Fig. 6 Tensile results of the examined alloys with various Fe contents (a) stress-strain curves, (b) relation between elastic modulus E and Fe content, and (c) trend lines of strength and elongation vs. Fe content, E, YS and TS is the short form of elastic modulus, yield strength and tensile strength, respectively
17 / 18
Table caption Table 1 Actual alloy compositions of the examined TiZrAlFe alloys, wt% Alloys
Ti
Zr
Al
Fe
F05
47.51
47.51
4.47
0.51
F10
47.15
47.39
4.47
0.99
F15
47.30
47.99
4.56
1.51
F20
46.76
46.86
4.41
1.97
Table 2 effect of Fe content on the phase structure of the examined alloys Lattice constant, nm Alloys
Phases composition a α' (hcp)
0.3118(3)
β (bcc)
0.3393(4)
α" (orthorhombic)
0.3099(9)
β
0.3389(5)
F15
β
0.3385(3)
F20
β
0.3376(8)
b
c 0.4825(6)
F05
F10
18 / 18
0.4720(9)
0.5154(1)
Figure 1
Figure 2
Figure 3
Figure 4a
Figure 4b
Figure 4c
Figure 4d
Figure 5a
Figure 5b
Figure 6a
Figure 6b
Figure 6c