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Mechanical alloying by friction surfacing process
Materials Letters 254 (2019) 394–397
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Mechanical alloying by friction surfacing process Seyedeh Marjan Bararpour, Hamed Jamshidi Aval ⇑, Roohollah Jamaati Department of Materials Engineering, Babol Noshirvani University of Technology, Shariati Avenue, Babol 47148-71167, Iran
a r t i c l e
i n f o
Article history: Received 15 May 2019 Received in revised form 10 July 2019 Accepted 28 July 2019 Available online 29 July 2019 Keywords: Friction surfacing Mechanical alloying Metals and alloys Microstructure
a b s t r a c t The present study for the first time demonstrates that friction surfacing can be applied as a process of mechanical alloying. The Zn powder was added to the coating through insertion of the hole in the consumable AA5083 rod. Zn dissolution and production of a solid solution during friction surfacing confirmed by X-ray diffraction. The results showed a solid solution, which was formed during friction surfacing and decomposed due to artificial aging, resulting in the formation of AlMg4Zn11 precipitates. Moreover, abnormal grain growth was observed in the coating after solid solution and aging treatment. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction Friction surfacing, a solid-state process, has multiple surface engineering applications. This method is mainly used to produce fine-grained coatings with better abrasion and corrosion properties. Friction surfacing is associated with plastic deformation of the consumable rod. The rotary consumable rod is compressed under the axial load applied to the substrate, and a viscoplastic boundary layer is formed by frictional heat at the consumable rod tip. In recent years, a number of researchers have studied the production of metal matrix composite by friction surfacing [1–4]. By induction of very large deformations at relatively low temperatures, severe plastic deformation (SPD), including torsion straining under high pressure and equal channel angular pressing, has been suggested to improve the local properties of the material through changes in the microstructure and chemical composition by mechanical alloying [5]. Aside from the abovementioned methods, friction surfacing and friction stir processing may be applied to synthesize and produce new materials through intermetallic formation or mechanical alloying in situ. Heat and severe plastic deformation during the friction surfacing process can be used as an agent for in-situ alloying. Based on the phase diagram, metal particles in the aluminum matrix act in two ways. Highly soluble particles can form solid solutions and, others with low solubility form intermetallic compounds. In the latter case, these particles can act as strengthening particles [6]. In this research, for the first time, it is tried to investigate the feasibility of alloying along the friction surfacing process on the AA5052 aluminum substrate ⇑ Corresponding author. E-mail address: [email protected] (H. Jamshidi Aval). https://doi.org/10.1016/j.matlet.2019.07.113 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
using zinc powder and its application through the insertion of hole in the AA5083 aluminum rod. The high solubility of zinc in aluminum (about 82.8 wt% at 381 °C [7]) increases the possibility of forming a solid solution during the process. 2. Experimental procedure The friction surfacing process was performed using a sheet of AA5052 (2.21% Mg, 0.04% Cu, 0.08% Mn, 0.09% Si, 0.21% Fe, Al balance, in wt%) with the thickness of 2 mm as the substrate and a consumable rod made of AA5083 (4.00% Mg, 0.06% Cu, 0.51% Mn, 0.13% Si, 0.12% Fe, Al balance, in wt%). The diameter and length of the AA5083 aluminum alloy consumable rods used in this study are 20 mm and 100 mm, respectively. According to the preliminary studies the maximum deposition efficiency achieved at axial feeding rate 125 mm / min, traverse speed 125 mm / min and rotational speed 800 rpm. Therefore, these parameters were used in the friction surfacing experiments. The Zinc powders were packed inside 2.5 mm diameter holes, drilled with a 30 mm depth. Four holes were placed at a 3 mm radial distance from the center and at an angle of 90° relative to each other. The Zinc powders with 2.5 mm median size were used. Deposition without Zinc powders was also performed. After coating the substrate by friction surfacing, samples of appropriate size were prepared to analyse the microstructure of the coating layer throughout its cross section. The samples were polished and treated with the Poulton’s etching reagent (0.5 ml HF, 15.5 ml HNO3, 84 ml H2O, and 0.3gr Cr2O3) to reveal the grain boundaries in the microstructure. X-ray diffraction (XRD) equipment Philips PW1730 were used for evaluating the coated samples. Brinell hardness tests were carried out on the friction surfaced
S.M. Bararpour et al. / Materials Letters 254 (2019) 394–397
samples using Koopa UV1 hardness tester with 15 kg load and 10 s dwell time. 3. Results and discussion Fig. 1 presents the microstructure of AA5083 consumable rod and friction surfaced (FSed) samples. The observations revealed a fine-grained microstructure in the FSed samples, compared to the AA5083 rod. In the severe plastic deformation of Al alloys, dynamic recrystallization (DRX) forms fine grains during FS. Different mechanisms, such as discontinuous dynamic recrystallization (DDRX), dynamic recovery (DRV), geometric dynamic recrystallization (GDRX), and continuous dynamic recrystallization (CDRX), seem to operate [8–10]. The stacking fault energy is a significant parameter, which can affect recovery in case of high-temperature deformation, as it indicates the simplicity of the cross-slip process and dislocation climb. Overall, alloying reduces the Al stacking fault energy. Nevertheless, Zn, which has a high stacking fault energy (220 mJ/m2), cannot significantly alter that of Al (188 mJ/m2) in alloying [11,12]. Therefore, addition of Zn is not expected to affect the overall grain refinement mechanism of Al in friction surfacing. It should be noted that, although Zn has no effect on the overall recrystallization and the formation of equiaxed grains, the average grain size of the coating in the Zn-containing and non-Zn samples
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are 15.2 and 17.5 mm, respectively. The smaller grain size in the Zncontaining sample was related to the effect of the solid solution pinning by reducing the driving force of the grain boundary migration [13,14] during dynamic recrystallization. Fig. 2 shows the XRD pattern of the coated samples with and without Zn addition. It can be seen coated sample with Zn did not exhibit any detectable peak of Zn. Two intermetallic Al6(Fe, Mn) and Mg2Si are observed in the XRD pattern of both samples. According to XRD results show in the Fig. 2, the peaks of Al for friction surfaced sample with Zn addition were shifted to higher angles in comparison to friction surfaced sample without Zn addition, indicating decrease in the lattice parameter. According to [7] due to smaller atomic radius of Zn compared to that of aluminum the observed decrease in the lattice parameter after FS indicates the formation of solid solution. As can be seen in the Fig. 2, after homogenizing at 375 °C and aging at 180 °C for 12 h, the friction surfaced sample with Zn powder indicates AlMg4Zn11 precipitates while it cannot be seen in the FSed sample without Zn. Fig. 3 shows the Brinell hardness of FSed samples with and without Zn powders. Also, the hardness variation of FSed sample after homogenization and artificial aging was shown in this figure. It can be seen that in the FSed sample with Zn powder in the asreceived (without any post heat treatment) condition the coating hardness is higher than sample without Zn powder. This is another
Fig. 1. The microstructure of a) consumable rod cross section, b) consumable rod with higher magnification, c) coated sample with Zn powder, d) coated sample without Zn powder.
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Fig. 2. XRD plots for coated samples before and after aging treatment.
Fig. 3. Average hardness of coated samples before and after aging treatment.
Fig. 4. The microstructure of coated sample with Zn powder after heat treatment; a) lower magnification, b) higher magnification.
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evidence of the Zn solution during friction surfacing and solid solution strengthening in Zn contained sample. Also, due to finer grain size of Zn contained sample, grain boundary strengthening mechanism can effect on the hardness of coating. The homogenization and solution treatment enhances the formation of a solid solution, and subsequently encourages the precipitation rate during aging. Although precipitation and hardness increasing are observed after solution treatment and aging, evidence of abnormal grain growth is observed in the coated sample (Fig. 4). This phenomena can reduced hardness increasing of coated sample after heat treatment. 4. Conclusions This study investigated the feasibility of alloying along the friction surfacing process on the AA5052 aluminum substrate using zinc powder and its application through the insertion of hole in the AA5083 aluminum rod. The conclusions drawn from the results can be summarized as follows: - Addition Zn will not affect the overall mechanism of grain refinement of aluminum during friction surfacing. Also, Zncontaining sample due to the solid solution pinning has smaller grain size than other sample. - Heat and plastic deformation during friction surfacing result in formation of solid solution. The homogenization and solution treatment enhances the formation of a solid solution, and subsequently encourages the precipitation of AlMg4Zn11 precipitates in the coated samples. - The solid solution strengthening and grain boundary strengthening mechanism in Zn contained sample result in higher hardness in this sample. Abnormal grain growth after heat treatment can reduced hardness increasing of coated sample.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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Acknowledgement The authors acknowledge the funding support of Babol Noshirvani University of Technology through Grant program No. BNUT/370167/98 and BNUT/393044/98. References [1] G.M. Reddy, K.S. Prasad, K.S. Rao, T. Mohandas, Friction surfacing of titanium alloy with aluminium metal matrix composite, Surf. Eng. 27 (2011) 92–98. [2] G.M. Reddy, K.S. Rao, T. Mohandas, Friction surfacing: novel technique for metal matrix composite coating on aluminium–silicon alloy, Surf. Eng. 25 (2009) 25–30. [3] J. Gandra, P. Vigarinho, D. Pereira, R. Miranda, A. Velhinho, P. Vilaça, Wear characterization of functionally graded Al–SiC composite coatings produced by friction surfacing, Mater. Des. (1980–2015) 52 (2013) 373–383. [4] G. Bedfordt, R. Sharp, B. Wilson, L. Elias, Production of friction surfaced components using steel metal matrix composites produced by Osprey process, Surf. Eng. 10 (1994) 118–122. [5] D. Ahmadkhaniha, P. Asadi, Mechanical alloying by friction stir processing, in: Advances in Friction Stir Welding and Processing, Woodhead Publishing, London, 2014, pp. 387–425. [6] S. Suwas, G. Upadhyaya, Powder metallurgy processing of aluminide intermetallics, ChemInform 28 (1997) no-no. [7] D. Yadav, R. Bauri, N. Chawake, Fabrication of Al-Zn solid solution via friction stir processing, Mater. Charact. 136 (2018) 221–228. [8] R.S. Mishra, Z. Ma, Friction stir welding and processing, in: Materials Science and Engineering: R: Reports, 2005, pp. 1–78. [9] J.-Q. Su, T.W. Nelson, C.J. Sterling, Microstructure evolution during FSW/FSP of high strength aluminum alloys, Mater. Sci. Eng. A 405 (2005) 277–286. [10] U. Suhuddin, S. Mironov, H. Krohn, M. Beyer, J. Dos Santos, Microstructural evolution during friction surfacing of dissimilar aluminum alloys, Metall. Mater. Trans. A 43 (2012) 5224–5231. [11] P. Dobson, R.E. Smallman, The climb of dislocation loops in zinc, in: Proceedings of the Royal Society of London Series A Mathematical and Physical Sciences, 1966, pp. 423–431. [12] G. Karmakar, R. Sen, S. Chattopadhyay, A. Meikap, S. Chatterjee, Effect of alloying with zinc on SFE of aluminium by study of lattice imperfections in cold worked Al-Zn alloys, Bull. Mater. Sci. 25 (2002) 315–317. [13] K. Wada, K. Takeshima, T. Uesugi, Y. Takigawa, K. Higashi, Effects of solute Fe, Zn and Mg on recrystallization in aluminum, Mater. Trans. 57 (2016) 329–334. [14] Chandrasekaran D. Grain size and solid solution strengthening in metals: Materialvetenskap, 2003.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Mechanical alloying by friction surfacing process Seyedeh Marjan Bararpour, Hamed Jamshidi Aval ⇑, Roohollah Jamaati Department of Materials Engineering, Babol Noshirvani University of Technology, Shariati Avenue, Babol 47148-71167, Iran
a r t i c l e
i n f o
Article history: Received 15 May 2019 Received in revised form 10 July 2019 Accepted 28 July 2019 Available online 29 July 2019 Keywords: Friction surfacing Mechanical alloying Metals and alloys Microstructure
a b s t r a c t The present study for the first time demonstrates that friction surfacing can be applied as a process of mechanical alloying. The Zn powder was added to the coating through insertion of the hole in the consumable AA5083 rod. Zn dissolution and production of a solid solution during friction surfacing confirmed by X-ray diffraction. The results showed a solid solution, which was formed during friction surfacing and decomposed due to artificial aging, resulting in the formation of AlMg4Zn11 precipitates. Moreover, abnormal grain growth was observed in the coating after solid solution and aging treatment. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction Friction surfacing, a solid-state process, has multiple surface engineering applications. This method is mainly used to produce fine-grained coatings with better abrasion and corrosion properties. Friction surfacing is associated with plastic deformation of the consumable rod. The rotary consumable rod is compressed under the axial load applied to the substrate, and a viscoplastic boundary layer is formed by frictional heat at the consumable rod tip. In recent years, a number of researchers have studied the production of metal matrix composite by friction surfacing [1–4]. By induction of very large deformations at relatively low temperatures, severe plastic deformation (SPD), including torsion straining under high pressure and equal channel angular pressing, has been suggested to improve the local properties of the material through changes in the microstructure and chemical composition by mechanical alloying [5]. Aside from the abovementioned methods, friction surfacing and friction stir processing may be applied to synthesize and produce new materials through intermetallic formation or mechanical alloying in situ. Heat and severe plastic deformation during the friction surfacing process can be used as an agent for in-situ alloying. Based on the phase diagram, metal particles in the aluminum matrix act in two ways. Highly soluble particles can form solid solutions and, others with low solubility form intermetallic compounds. In the latter case, these particles can act as strengthening particles [6]. In this research, for the first time, it is tried to investigate the feasibility of alloying along the friction surfacing process on the AA5052 aluminum substrate ⇑ Corresponding author. E-mail address: [email protected] (H. Jamshidi Aval). https://doi.org/10.1016/j.matlet.2019.07.113 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
using zinc powder and its application through the insertion of hole in the AA5083 aluminum rod. The high solubility of zinc in aluminum (about 82.8 wt% at 381 °C [7]) increases the possibility of forming a solid solution during the process. 2. Experimental procedure The friction surfacing process was performed using a sheet of AA5052 (2.21% Mg, 0.04% Cu, 0.08% Mn, 0.09% Si, 0.21% Fe, Al balance, in wt%) with the thickness of 2 mm as the substrate and a consumable rod made of AA5083 (4.00% Mg, 0.06% Cu, 0.51% Mn, 0.13% Si, 0.12% Fe, Al balance, in wt%). The diameter and length of the AA5083 aluminum alloy consumable rods used in this study are 20 mm and 100 mm, respectively. According to the preliminary studies the maximum deposition efficiency achieved at axial feeding rate 125 mm / min, traverse speed 125 mm / min and rotational speed 800 rpm. Therefore, these parameters were used in the friction surfacing experiments. The Zinc powders were packed inside 2.5 mm diameter holes, drilled with a 30 mm depth. Four holes were placed at a 3 mm radial distance from the center and at an angle of 90° relative to each other. The Zinc powders with 2.5 mm median size were used. Deposition without Zinc powders was also performed. After coating the substrate by friction surfacing, samples of appropriate size were prepared to analyse the microstructure of the coating layer throughout its cross section. The samples were polished and treated with the Poulton’s etching reagent (0.5 ml HF, 15.5 ml HNO3, 84 ml H2O, and 0.3gr Cr2O3) to reveal the grain boundaries in the microstructure. X-ray diffraction (XRD) equipment Philips PW1730 were used for evaluating the coated samples. Brinell hardness tests were carried out on the friction surfaced
S.M. Bararpour et al. / Materials Letters 254 (2019) 394–397
samples using Koopa UV1 hardness tester with 15 kg load and 10 s dwell time. 3. Results and discussion Fig. 1 presents the microstructure of AA5083 consumable rod and friction surfaced (FSed) samples. The observations revealed a fine-grained microstructure in the FSed samples, compared to the AA5083 rod. In the severe plastic deformation of Al alloys, dynamic recrystallization (DRX) forms fine grains during FS. Different mechanisms, such as discontinuous dynamic recrystallization (DDRX), dynamic recovery (DRV), geometric dynamic recrystallization (GDRX), and continuous dynamic recrystallization (CDRX), seem to operate [8–10]. The stacking fault energy is a significant parameter, which can affect recovery in case of high-temperature deformation, as it indicates the simplicity of the cross-slip process and dislocation climb. Overall, alloying reduces the Al stacking fault energy. Nevertheless, Zn, which has a high stacking fault energy (220 mJ/m2), cannot significantly alter that of Al (188 mJ/m2) in alloying [11,12]. Therefore, addition of Zn is not expected to affect the overall grain refinement mechanism of Al in friction surfacing. It should be noted that, although Zn has no effect on the overall recrystallization and the formation of equiaxed grains, the average grain size of the coating in the Zn-containing and non-Zn samples
395
are 15.2 and 17.5 mm, respectively. The smaller grain size in the Zncontaining sample was related to the effect of the solid solution pinning by reducing the driving force of the grain boundary migration [13,14] during dynamic recrystallization. Fig. 2 shows the XRD pattern of the coated samples with and without Zn addition. It can be seen coated sample with Zn did not exhibit any detectable peak of Zn. Two intermetallic Al6(Fe, Mn) and Mg2Si are observed in the XRD pattern of both samples. According to XRD results show in the Fig. 2, the peaks of Al for friction surfaced sample with Zn addition were shifted to higher angles in comparison to friction surfaced sample without Zn addition, indicating decrease in the lattice parameter. According to [7] due to smaller atomic radius of Zn compared to that of aluminum the observed decrease in the lattice parameter after FS indicates the formation of solid solution. As can be seen in the Fig. 2, after homogenizing at 375 °C and aging at 180 °C for 12 h, the friction surfaced sample with Zn powder indicates AlMg4Zn11 precipitates while it cannot be seen in the FSed sample without Zn. Fig. 3 shows the Brinell hardness of FSed samples with and without Zn powders. Also, the hardness variation of FSed sample after homogenization and artificial aging was shown in this figure. It can be seen that in the FSed sample with Zn powder in the asreceived (without any post heat treatment) condition the coating hardness is higher than sample without Zn powder. This is another
Fig. 1. The microstructure of a) consumable rod cross section, b) consumable rod with higher magnification, c) coated sample with Zn powder, d) coated sample without Zn powder.
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Fig. 2. XRD plots for coated samples before and after aging treatment.
Fig. 3. Average hardness of coated samples before and after aging treatment.
Fig. 4. The microstructure of coated sample with Zn powder after heat treatment; a) lower magnification, b) higher magnification.
S.M. Bararpour et al. / Materials Letters 254 (2019) 394–397
evidence of the Zn solution during friction surfacing and solid solution strengthening in Zn contained sample. Also, due to finer grain size of Zn contained sample, grain boundary strengthening mechanism can effect on the hardness of coating. The homogenization and solution treatment enhances the formation of a solid solution, and subsequently encourages the precipitation rate during aging. Although precipitation and hardness increasing are observed after solution treatment and aging, evidence of abnormal grain growth is observed in the coated sample (Fig. 4). This phenomena can reduced hardness increasing of coated sample after heat treatment. 4. Conclusions This study investigated the feasibility of alloying along the friction surfacing process on the AA5052 aluminum substrate using zinc powder and its application through the insertion of hole in the AA5083 aluminum rod. The conclusions drawn from the results can be summarized as follows: - Addition Zn will not affect the overall mechanism of grain refinement of aluminum during friction surfacing. Also, Zncontaining sample due to the solid solution pinning has smaller grain size than other sample. - Heat and plastic deformation during friction surfacing result in formation of solid solution. The homogenization and solution treatment enhances the formation of a solid solution, and subsequently encourages the precipitation of AlMg4Zn11 precipitates in the coated samples. - The solid solution strengthening and grain boundary strengthening mechanism in Zn contained sample result in higher hardness in this sample. Abnormal grain growth after heat treatment can reduced hardness increasing of coated sample.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
397
Acknowledgement The authors acknowledge the funding support of Babol Noshirvani University of Technology through Grant program No. BNUT/370167/98 and BNUT/393044/98. References [1] G.M. Reddy, K.S. Prasad, K.S. Rao, T. Mohandas, Friction surfacing of titanium alloy with aluminium metal matrix composite, Surf. Eng. 27 (2011) 92–98. [2] G.M. Reddy, K.S. Rao, T. Mohandas, Friction surfacing: novel technique for metal matrix composite coating on aluminium–silicon alloy, Surf. Eng. 25 (2009) 25–30. [3] J. Gandra, P. Vigarinho, D. Pereira, R. Miranda, A. Velhinho, P. Vilaça, Wear characterization of functionally graded Al–SiC composite coatings produced by friction surfacing, Mater. Des. (1980–2015) 52 (2013) 373–383. [4] G. Bedfordt, R. Sharp, B. Wilson, L. Elias, Production of friction surfaced components using steel metal matrix composites produced by Osprey process, Surf. Eng. 10 (1994) 118–122. [5] D. Ahmadkhaniha, P. Asadi, Mechanical alloying by friction stir processing, in: Advances in Friction Stir Welding and Processing, Woodhead Publishing, London, 2014, pp. 387–425. [6] S. Suwas, G. Upadhyaya, Powder metallurgy processing of aluminide intermetallics, ChemInform 28 (1997) no-no. [7] D. Yadav, R. Bauri, N. Chawake, Fabrication of Al-Zn solid solution via friction stir processing, Mater. Charact. 136 (2018) 221–228. [8] R.S. Mishra, Z. Ma, Friction stir welding and processing, in: Materials Science and Engineering: R: Reports, 2005, pp. 1–78. [9] J.-Q. Su, T.W. Nelson, C.J. Sterling, Microstructure evolution during FSW/FSP of high strength aluminum alloys, Mater. Sci. Eng. A 405 (2005) 277–286. [10] U. Suhuddin, S. Mironov, H. Krohn, M. Beyer, J. Dos Santos, Microstructural evolution during friction surfacing of dissimilar aluminum alloys, Metall. Mater. Trans. A 43 (2012) 5224–5231. [11] P. Dobson, R.E. Smallman, The climb of dislocation loops in zinc, in: Proceedings of the Royal Society of London Series A Mathematical and Physical Sciences, 1966, pp. 423–431. [12] G. Karmakar, R. Sen, S. Chattopadhyay, A. Meikap, S. Chatterjee, Effect of alloying with zinc on SFE of aluminium by study of lattice imperfections in cold worked Al-Zn alloys, Bull. Mater. Sci. 25 (2002) 315–317. [13] K. Wada, K. Takeshima, T. Uesugi, Y. Takigawa, K. Higashi, Effects of solute Fe, Zn and Mg on recrystallization in aluminum, Mater. Trans. 57 (2016) 329–334. [14] Chandrasekaran D. Grain size and solid solution strengthening in metals: Materialvetenskap, 2003.