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The phase equilibria in the Ti–Cu–Y ternary system at 773 K
Journal of Alloys and Compounds 485 (2009) 261–263
Contents lists available at ScienceDirect
Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jallcom
The phase equilibria in the Ti–Cu–Y ternary system at 773 K Zhaohua Hu, Yongzhong Zhan ∗ , Jia She, Guanghua Zhang, Dan Peng Key Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004, PR China
a r t i c l e
i n f o
Article history: Received 18 May 2009 Received in revised form 5 June 2009 Accepted 8 June 2009 Available online 17 June 2009 Keywords: Phase diagrams Metal alloys X-ray diffraction
a b s t r a c t Physical–chemical analysis apparatuses, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) were employed in constructing the isothermal section of the Ti–Cu–Y system at 773 K. The existences of 10 binary compounds, Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed. The isothermal section consists of 13 single-phase regions, 23 binary phase regions and 11 ternary phase regions. No ternary compound is found in this work. Except the binary compounds YCu6 and TiCu4 show homogeneity regions less than 1.5 at.%, none of the other phases in this system reveals a remarkable homogeneity range at 773 K. © 2009 Elsevier B.V. All rights reserved.
1. Introduction The Ti–Cu alloys have high strength and hardness, outstanding mechanical properties and corrosion resistance, as a result they have got increasingly attentions [1,2]. It is of great importance to improve and make use of the excellent properties of Ti–Cu alloys and step up their practical applications. Rare earth (RE) is an important kind of alloying additive for metallic materials. It is well known that the addition of small amount of rare earth element can improve the microstructures and properties of titanium alloys [3,4]. In order to discover further application characteristics and regularities concerning phase formation in the Ti–Cu–Y ternary system, it is necessary to investigate the phase relationships in the system. According to Kumar et al. [5], five intermediate phases are shown in the Ti–Cu binary phase diagram, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , and TiCu4 . Although Canale and Servant [6] recently suggested that Ti3 Cu is a stable phase on the basis of the experimental results, it should be a metastable phase in light of the works carried out subsequently by the other groups [7–10]. The Cu–Y phase diagram [11] shows five intermediate phases, i.e. Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY, and the previously reported Cu5 Y compound (CaCu5 structure type, space group P6/mmm) [12] has not been confirmed. In the Ti–Y phase diagram [13], there is no compound found at 773 K. Structure data for the intermetallic compounds in the binary systems are given in Table 1. Until now, no literature data is found concerning the phase relationships of the Ti–Cu–Y ternary system. The main purpose of the present work is to investigate experimentally the phase equilibria
∗ Corresponding author. Tel.: +86 771 3272311; fax: +86 771 3233530. E-mail address: [email protected] (Y. Zhan). 0925-8388/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2009.06.066
of Ti–Cu–Y phase diagram at 773 K, to meet the needs of researchers of Ti–Cu alloys with high performance. 2. Experimental procedure In this work, 119 alloy buttons (each weight 2 g) were prepared in an electric arc furnace under an argon atmosphere and a water-cooled cooper crucible. The purity of Ti, Cu and Y used in this work were all 99.99 wt.%. Titanium was used as an oxygen getter during the melting process. The alloys were re-melted more than three times in order to achieve complete fusion and homogeneous composition. For most alloys, the weight loss is less than 1% after melting. All the as-cast samples were sealed in evacuated quartz tubes for homogenization heat treatment. The homogenization temperature was determined by differential thermal analysis (DTA) or based on the previous work of the three binary phase diagrams [6,11,13]. Most samples were annealed at 1023 K for 720 h and then cooled at a rate of 3 K/h to 773 K and maintained for 350 h. Finally, they were quenched in liquid nitrogen. All the sample buttons were ground into powder for X-ray diffraction (XRD) analysis. The XRD analysis was performed on a Rigaku D/Max 2500 V diffractometer with Cu radiation and graphite monochromator operated at 40 kV, 200 mA. The Material Data Inc. software Jade 5.0 and powder diffraction file (PDF release 2002) were used for phase identification. Scanning electron microscopy with energy dispersive analysis (EDX) was used for microstructure analysis. By all these means, the phase relationship in the Ti–Cu–Y system was determined.
3. Results and discussion 3.1. Phase analysis In this work, the binary systems Ti–Cu, Ti–Y and Cu–Y at 773 K have been studied to identify the binary compounds before analysis of the ternary system. In the Ti–Cu [5] system, the existences of five compounds, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , and TiCu4 have been confirmed at 773 K. In Ref. [6], Canale and Servant suggested that the phase Ti3 Cu is a stable phase on the basis of their experimental results though it is generally regarded as a metastable phase. In this work, Ti3 Cu was not observed from the XRD patterns of the
262
Z. Hu et al. / Journal of Alloys and Compounds 485 (2009) 261–263
Table 1 Binary crystal structure data in the Ti–Cu–Y system. Compound
Space group
Ti2 Cu TiCu Ti3 Cu4 Ti2 Cu3 TiCu4 Cu6 Y Cu4 Y Cu2 Y CuY
I4/mmm P4/nmm I4/mmm P4/nmm Pnma P6/mmm P63 Imma ¯ Pm3m
Lattice parameters (nm)
Reference
a
b
c
0.29438 0.314 0.312 0.313 0.4522 0.4940 0.4960 0.4308(3) 0.3477
– – – – 0.4344 – – 0.6891(8) –
1.0786 0.2856 1.994 1.395 1.2897 0.4157 0.8240 0.7303(7) –
[14] [14] [14] [14] [14] [11,14,15] [16] [14] [14]
Fig. 1. The XRD pattern of #51 sample (86 at.% Ti, 10 at.% Cu, 4 at.% Y) indicating the phase equilibrium of Ti + Ti2 Cu + CuY.
Fig. 3. The XRD pattern of #59 sample (6 at.% Ti, 82 at.% Cu, 12 at.% Y) indicating the existence of TiCu4 , Cu4 Y and Cu6 Y.
equilibrated alloys with composition equal to or near to Ti:Cu = 3:1. Therefore, it is considered to be a metastable phase, that is, in accordance with the results of Kumar et al. [5] and Murray [16]. The XRD pattern of #51 sample (86 at.% Ti, 10 at.% Cu, 4 at.% Y) clearly indicated that the existence of the compound Ti2 Cu and the three-phase regions Ti + Ti2 Cu + CuY, as shown in Fig. 1. The binary phase diagram of Cu–Y system [11] shows five intermediate phases, namely, Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY. In this work, all the above compounds have been confirmed at 773 K. However, the existence of the Cu5 Y compound with CaCu5 structure type was not found, thus it is considered to be a metastable phase at 773 K. In the Ti–Y system, it is confirmed here that no binary compounds exists. This result is in good agreement with that reported in Ref. [13]. In the previous works, no ternary compounds have been reported in the ternary Ti–Cu–Y system. This result also has been confirmed in the present work at 773 K.
Fig. 2 shows an example of the XRD pattern of #29 sample containing 26 at.% Ti, 4 at.% Cu and 70 at.% Y. The result indicates that this equilibrated alloy consists of three phases, i.e. Ti, Y and CuY. The XRD pattern of #59 sample (6 at.% Ti, 82 at.% Cu, 12 at.% Y) belongs to patterns of three phases, i.e. TiCu4 , Cu4 Y, Cu6 Y, as shown in Fig. 3. The solid solubility ranges of all single phases in the isothermal section were determined by XRD using phase-disappearing method and comparing the shift of the XRD pattern of the samples near the compositions of the binary phases. For the binary compounds, i.e. YCu6 and TiCu4 , there exist homogeneity regions
Fig. 2. The XRD pattern of #29 sample (26 at.% Ti, 4 at.% Cu, 70 at.% Y) indicating the existence of Ti, Y and CuY.
Fig. 4. Isothermal section of the Ti–Cu–Y ternary system at 773 K.
Z. Hu et al. / Journal of Alloys and Compounds 485 (2009) 261–263 Table 2 Details of the three-phase regions and typical samples in the Ti–Cu–Y system at 773 K. Phase regions
1 2 3 4 5 6 7 8 9 10 11
Alloy composition (at.%)
Phase composition
Ti
Cu
Y
20 50 20 48 30 6 30 24 6 10 6
20 30 54 46 58 68 64 72 80 82 90
60 20 26 6 12 26 6 4 14 8 4
Ti + Y + CuY Ti + Ti2 Cu + CuY Ti2 Cu + CuY + Cu2 Y Ti2 Cu + TiCu + Cu2 Y TiCu + Ti3 Cu4 + Cu2 Y Ti3 Cu4 + Cu2 Y + Cu7 Y2 Ti3 Cu4 + Ti2 Cu3 + Cu7 Y2 Ti2 Cu3 + TiCu4 + Cu7 Y2 TiCu4 + Cu7 Y2 + Cu4 Y TiCu4 + Cu4 Y + Cu6 Y TiCu4 + Cu6 Y + Cu
both less than 1.5 at.%. For the other binary compounds, the results showed that the diffraction patterns did not show shift and the diffraction patterns of the second phase could easily be detected when the composition of the alloys deviated from its single-phase region by 1.0 at.%. Therefore, the other phases in this system do not reveal a remarkable homogeneity range at 773 K. 3.2. Isothermal section Mainly based on the XRD, SEM and DTA analysis, the phase equilibria of the ternary Ti–Cu–Y system at 773 K were presented. The existence of 10 binary compounds, Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed. The 773 K isothermal section of Ti–Cu–Y ternary system phase diagram is shown in Fig. 4. It consists of 13 single-phase regions, 23 binary phase regions and 11 ternary phase regions. Constitutions of the three-phase regions and compositions of the typical alloys are given in Table 2. 4. Conclusion By comparing and analyzing the XRD patterns of 119 equilibrated samples, the isothermal section of the phase diagram of
263
the Ti–Cu–Y ternary system at 773 K has been determined. The 773 K isothermal section consists of 13 single-phase regions, 23 two-phase regions and 11 three-phase regions. The existence of 10 binary compounds, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed at 773 K. For the binary compounds YCu6 and TiCu4 , there exist homogeneity regions less than 1.5 at.%. None of the other phases in this system has remarkable homogeneity range. No ternary compound was found in the ternary system. The Ti3 Cu and Cu5 Y compounds were not found. They were considered to be metastable phase at 773 K. Acknowledgements The authors wish to express thanks to the financial support of the National Natural Science Foundation of China (50761003, 50601006), the Key Project of China Ministry of Education (207085) and the Opening Foundation of State Key Laboratory of Powder Metallurgy. References [1] Z.Y. Suo, K.Q. Qiu, Q.F. Li, Y.L. Ren, Z.Q. Hu, J. Alloys Compd. 463 (2008) 564– 568. [2] S. Semboshi, T. Nishida, H. Numakura, Mater. Sci. Eng. A (2008), doi:10.1016/j.msea.2009.03.047. [3] Y. Liu, L.F. Chen, W.F. Wei, H.P. Tang, B. Liu, B.Y. Huang, J. Mater. Sci. Technol. 22 (4) (2006) 465–546. [4] K. Xia, W. Li, C. Liu, Scripta Mater. 41 (1) (1999) 67–73. [5] K.C.H. Kumar, I. Ansara, P. Wollants, L. Delaey, Z. Metallkd. 87 (1996) 666– 672. [6] P. Canale, C. Servant, Z. Metallkd. 93 (2002) 273–276. [7] K.P. Gupta, J. Phase Equilib. 24 (3) (2003) 272–275. [8] K.P. Gupta, J. Phase Equilib. 23 (6) (2002) 541–547. [9] H.H. Xu, Y. Du, B.Y. Huang, S.H. Liu, J. Alloys Compd. 399 (2005) 92–95. [10] Y.M. Wang, H.S. Liu, F. Zheng, Q. Chen, Z.P. Jin, Mater. Sci. Eng. A 431 (2006) 184–190. [11] H. Okamoto, J. Phase Equilib. 19 (4) (1998) 398–399. [12] J.H. Wernick, S. Geller, Acta Crystallogr. 12 (1959) 662. [13] B.J. Beaudry, J. Less-Common Met. 14 (1968) 370–372. [14] P. Villars, Pearson’s Handbook of Crystallographic Data, ASM International, Materials Park, OH, 1997, pp. 1600–1602. [15] H. Okamoto, J. Phase Equilib. 13 (1) (1992) 102–103. [16] J.L. Murray, Bull. Alloy Phase Diagrams 4 (1983) 81–95.
Contents lists available at ScienceDirect
Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jallcom
The phase equilibria in the Ti–Cu–Y ternary system at 773 K Zhaohua Hu, Yongzhong Zhan ∗ , Jia She, Guanghua Zhang, Dan Peng Key Laboratory of Nonferrous Metal Materials and New Processing Technology, Ministry of Education, Guangxi University, Nanning, Guangxi 530004, PR China
a r t i c l e
i n f o
Article history: Received 18 May 2009 Received in revised form 5 June 2009 Accepted 8 June 2009 Available online 17 June 2009 Keywords: Phase diagrams Metal alloys X-ray diffraction
a b s t r a c t Physical–chemical analysis apparatuses, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) were employed in constructing the isothermal section of the Ti–Cu–Y system at 773 K. The existences of 10 binary compounds, Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed. The isothermal section consists of 13 single-phase regions, 23 binary phase regions and 11 ternary phase regions. No ternary compound is found in this work. Except the binary compounds YCu6 and TiCu4 show homogeneity regions less than 1.5 at.%, none of the other phases in this system reveals a remarkable homogeneity range at 773 K. © 2009 Elsevier B.V. All rights reserved.
1. Introduction The Ti–Cu alloys have high strength and hardness, outstanding mechanical properties and corrosion resistance, as a result they have got increasingly attentions [1,2]. It is of great importance to improve and make use of the excellent properties of Ti–Cu alloys and step up their practical applications. Rare earth (RE) is an important kind of alloying additive for metallic materials. It is well known that the addition of small amount of rare earth element can improve the microstructures and properties of titanium alloys [3,4]. In order to discover further application characteristics and regularities concerning phase formation in the Ti–Cu–Y ternary system, it is necessary to investigate the phase relationships in the system. According to Kumar et al. [5], five intermediate phases are shown in the Ti–Cu binary phase diagram, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , and TiCu4 . Although Canale and Servant [6] recently suggested that Ti3 Cu is a stable phase on the basis of the experimental results, it should be a metastable phase in light of the works carried out subsequently by the other groups [7–10]. The Cu–Y phase diagram [11] shows five intermediate phases, i.e. Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY, and the previously reported Cu5 Y compound (CaCu5 structure type, space group P6/mmm) [12] has not been confirmed. In the Ti–Y phase diagram [13], there is no compound found at 773 K. Structure data for the intermetallic compounds in the binary systems are given in Table 1. Until now, no literature data is found concerning the phase relationships of the Ti–Cu–Y ternary system. The main purpose of the present work is to investigate experimentally the phase equilibria
∗ Corresponding author. Tel.: +86 771 3272311; fax: +86 771 3233530. E-mail address: [email protected] (Y. Zhan). 0925-8388/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2009.06.066
of Ti–Cu–Y phase diagram at 773 K, to meet the needs of researchers of Ti–Cu alloys with high performance. 2. Experimental procedure In this work, 119 alloy buttons (each weight 2 g) were prepared in an electric arc furnace under an argon atmosphere and a water-cooled cooper crucible. The purity of Ti, Cu and Y used in this work were all 99.99 wt.%. Titanium was used as an oxygen getter during the melting process. The alloys were re-melted more than three times in order to achieve complete fusion and homogeneous composition. For most alloys, the weight loss is less than 1% after melting. All the as-cast samples were sealed in evacuated quartz tubes for homogenization heat treatment. The homogenization temperature was determined by differential thermal analysis (DTA) or based on the previous work of the three binary phase diagrams [6,11,13]. Most samples were annealed at 1023 K for 720 h and then cooled at a rate of 3 K/h to 773 K and maintained for 350 h. Finally, they were quenched in liquid nitrogen. All the sample buttons were ground into powder for X-ray diffraction (XRD) analysis. The XRD analysis was performed on a Rigaku D/Max 2500 V diffractometer with Cu radiation and graphite monochromator operated at 40 kV, 200 mA. The Material Data Inc. software Jade 5.0 and powder diffraction file (PDF release 2002) were used for phase identification. Scanning electron microscopy with energy dispersive analysis (EDX) was used for microstructure analysis. By all these means, the phase relationship in the Ti–Cu–Y system was determined.
3. Results and discussion 3.1. Phase analysis In this work, the binary systems Ti–Cu, Ti–Y and Cu–Y at 773 K have been studied to identify the binary compounds before analysis of the ternary system. In the Ti–Cu [5] system, the existences of five compounds, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , and TiCu4 have been confirmed at 773 K. In Ref. [6], Canale and Servant suggested that the phase Ti3 Cu is a stable phase on the basis of their experimental results though it is generally regarded as a metastable phase. In this work, Ti3 Cu was not observed from the XRD patterns of the
262
Z. Hu et al. / Journal of Alloys and Compounds 485 (2009) 261–263
Table 1 Binary crystal structure data in the Ti–Cu–Y system. Compound
Space group
Ti2 Cu TiCu Ti3 Cu4 Ti2 Cu3 TiCu4 Cu6 Y Cu4 Y Cu2 Y CuY
I4/mmm P4/nmm I4/mmm P4/nmm Pnma P6/mmm P63 Imma ¯ Pm3m
Lattice parameters (nm)
Reference
a
b
c
0.29438 0.314 0.312 0.313 0.4522 0.4940 0.4960 0.4308(3) 0.3477
– – – – 0.4344 – – 0.6891(8) –
1.0786 0.2856 1.994 1.395 1.2897 0.4157 0.8240 0.7303(7) –
[14] [14] [14] [14] [14] [11,14,15] [16] [14] [14]
Fig. 1. The XRD pattern of #51 sample (86 at.% Ti, 10 at.% Cu, 4 at.% Y) indicating the phase equilibrium of Ti + Ti2 Cu + CuY.
Fig. 3. The XRD pattern of #59 sample (6 at.% Ti, 82 at.% Cu, 12 at.% Y) indicating the existence of TiCu4 , Cu4 Y and Cu6 Y.
equilibrated alloys with composition equal to or near to Ti:Cu = 3:1. Therefore, it is considered to be a metastable phase, that is, in accordance with the results of Kumar et al. [5] and Murray [16]. The XRD pattern of #51 sample (86 at.% Ti, 10 at.% Cu, 4 at.% Y) clearly indicated that the existence of the compound Ti2 Cu and the three-phase regions Ti + Ti2 Cu + CuY, as shown in Fig. 1. The binary phase diagram of Cu–Y system [11] shows five intermediate phases, namely, Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY. In this work, all the above compounds have been confirmed at 773 K. However, the existence of the Cu5 Y compound with CaCu5 structure type was not found, thus it is considered to be a metastable phase at 773 K. In the Ti–Y system, it is confirmed here that no binary compounds exists. This result is in good agreement with that reported in Ref. [13]. In the previous works, no ternary compounds have been reported in the ternary Ti–Cu–Y system. This result also has been confirmed in the present work at 773 K.
Fig. 2 shows an example of the XRD pattern of #29 sample containing 26 at.% Ti, 4 at.% Cu and 70 at.% Y. The result indicates that this equilibrated alloy consists of three phases, i.e. Ti, Y and CuY. The XRD pattern of #59 sample (6 at.% Ti, 82 at.% Cu, 12 at.% Y) belongs to patterns of three phases, i.e. TiCu4 , Cu4 Y, Cu6 Y, as shown in Fig. 3. The solid solubility ranges of all single phases in the isothermal section were determined by XRD using phase-disappearing method and comparing the shift of the XRD pattern of the samples near the compositions of the binary phases. For the binary compounds, i.e. YCu6 and TiCu4 , there exist homogeneity regions
Fig. 2. The XRD pattern of #29 sample (26 at.% Ti, 4 at.% Cu, 70 at.% Y) indicating the existence of Ti, Y and CuY.
Fig. 4. Isothermal section of the Ti–Cu–Y ternary system at 773 K.
Z. Hu et al. / Journal of Alloys and Compounds 485 (2009) 261–263 Table 2 Details of the three-phase regions and typical samples in the Ti–Cu–Y system at 773 K. Phase regions
1 2 3 4 5 6 7 8 9 10 11
Alloy composition (at.%)
Phase composition
Ti
Cu
Y
20 50 20 48 30 6 30 24 6 10 6
20 30 54 46 58 68 64 72 80 82 90
60 20 26 6 12 26 6 4 14 8 4
Ti + Y + CuY Ti + Ti2 Cu + CuY Ti2 Cu + CuY + Cu2 Y Ti2 Cu + TiCu + Cu2 Y TiCu + Ti3 Cu4 + Cu2 Y Ti3 Cu4 + Cu2 Y + Cu7 Y2 Ti3 Cu4 + Ti2 Cu3 + Cu7 Y2 Ti2 Cu3 + TiCu4 + Cu7 Y2 TiCu4 + Cu7 Y2 + Cu4 Y TiCu4 + Cu4 Y + Cu6 Y TiCu4 + Cu6 Y + Cu
both less than 1.5 at.%. For the other binary compounds, the results showed that the diffraction patterns did not show shift and the diffraction patterns of the second phase could easily be detected when the composition of the alloys deviated from its single-phase region by 1.0 at.%. Therefore, the other phases in this system do not reveal a remarkable homogeneity range at 773 K. 3.2. Isothermal section Mainly based on the XRD, SEM and DTA analysis, the phase equilibria of the ternary Ti–Cu–Y system at 773 K were presented. The existence of 10 binary compounds, Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed. The 773 K isothermal section of Ti–Cu–Y ternary system phase diagram is shown in Fig. 4. It consists of 13 single-phase regions, 23 binary phase regions and 11 ternary phase regions. Constitutions of the three-phase regions and compositions of the typical alloys are given in Table 2. 4. Conclusion By comparing and analyzing the XRD patterns of 119 equilibrated samples, the isothermal section of the phase diagram of
263
the Ti–Cu–Y ternary system at 773 K has been determined. The 773 K isothermal section consists of 13 single-phase regions, 23 two-phase regions and 11 three-phase regions. The existence of 10 binary compounds, i.e. Ti2 Cu, TiCu, Ti3 Cu4 , Ti2 Cu3 , TiCu4 , Cu6 Y, Cu4 Y, Cu7 Y2 , Cu2 Y and CuY were confirmed at 773 K. For the binary compounds YCu6 and TiCu4 , there exist homogeneity regions less than 1.5 at.%. None of the other phases in this system has remarkable homogeneity range. No ternary compound was found in the ternary system. The Ti3 Cu and Cu5 Y compounds were not found. They were considered to be metastable phase at 773 K. Acknowledgements The authors wish to express thanks to the financial support of the National Natural Science Foundation of China (50761003, 50601006), the Key Project of China Ministry of Education (207085) and the Opening Foundation of State Key Laboratory of Powder Metallurgy. References [1] Z.Y. Suo, K.Q. Qiu, Q.F. Li, Y.L. Ren, Z.Q. Hu, J. Alloys Compd. 463 (2008) 564– 568. [2] S. Semboshi, T. Nishida, H. Numakura, Mater. Sci. Eng. A (2008), doi:10.1016/j.msea.2009.03.047. [3] Y. Liu, L.F. Chen, W.F. Wei, H.P. Tang, B. Liu, B.Y. Huang, J. Mater. Sci. Technol. 22 (4) (2006) 465–546. [4] K. Xia, W. Li, C. Liu, Scripta Mater. 41 (1) (1999) 67–73. [5] K.C.H. Kumar, I. Ansara, P. Wollants, L. Delaey, Z. Metallkd. 87 (1996) 666– 672. [6] P. Canale, C. Servant, Z. Metallkd. 93 (2002) 273–276. [7] K.P. Gupta, J. Phase Equilib. 24 (3) (2003) 272–275. [8] K.P. Gupta, J. Phase Equilib. 23 (6) (2002) 541–547. [9] H.H. Xu, Y. Du, B.Y. Huang, S.H. Liu, J. Alloys Compd. 399 (2005) 92–95. [10] Y.M. Wang, H.S. Liu, F. Zheng, Q. Chen, Z.P. Jin, Mater. Sci. Eng. A 431 (2006) 184–190. [11] H. Okamoto, J. Phase Equilib. 19 (4) (1998) 398–399. [12] J.H. Wernick, S. Geller, Acta Crystallogr. 12 (1959) 662. [13] B.J. Beaudry, J. Less-Common Met. 14 (1968) 370–372. [14] P. Villars, Pearson’s Handbook of Crystallographic Data, ASM International, Materials Park, OH, 1997, pp. 1600–1602. [15] H. Okamoto, J. Phase Equilib. 13 (1) (1992) 102–103. [16] J.L. Murray, Bull. Alloy Phase Diagrams 4 (1983) 81–95.