Evolution of microstructure and texture in copper during repetitive extrusion-upsetting and subsequent annealing

doi:10.1016/j.jmst.2017.03.003

Abstract

Abstract:

The evolution of the microstructure and texture in copper has been studied during repetitive extrusion-upsetting (REU) to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 〈001〉 + 〈111〉 fiber texture with an increased 〈111〉 component is observed after each extrusion pass, whereas the 〈110〉 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200 °C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350 °C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.

Key words: Severe plastic deformation, Repetitive extrusion-upsetting, Copper, Deformation microstructure, Texture, Annealing

Chen Q., Shu D.Y., Lin J., Wu Y., Xia X.S., Huang S.H., Zhao Z.D., Mishin O.V., Wu G.L.. Evolution of microstructure and texture in copper during repetitive extrusion-upsetting and subsequent annealing[J]. J. Mater. Sci. Technol., 2017, 33(7): 690-697.

Figures/Tables 13

Fig. 1. Schematic illustration of the REU process.

Fig. 2. EBSD data for the initial material: (a) orientation map, where different colors correspond to different crystallographic directions along the LD, as shown in the inset. HABs are shown as black lines; (b) distribution of misorientation angles.

Fig. 3. Optical micrographs of copper samples after different REU passes: (a) first extrusion; (b) first upsetting; (c) second extrusion; (d) second upsetting. The LD is parallel to the scale bar.

Fig. 4. Orientation maps showing the microstructure of copper samples after different REU passes: (a) first extrusion; (b) first upsetting; (c) second extrusion; (d) second upsetting. The color code is shown in the inset in (a). Recrystallized grains in (d) are marked “RX”. HABs are shown as black lines. The LD is parallel to the scale bar.

Fig. 5. Evolution of microstructural parameters in copper during the REU process: (a) average grain (cell) size; (b) fraction of HABs. Labels “E1”, “U1”, “E2” and “U2” correspond to extrusion and upsetting passes in the first and second cycles.

Fig. 6. Distribution of misorientation angles in copper after 2 REU cycles.

Fig. 7. Evolution of Vickers hardness in copper during the REU process. Labels “E1”, “U1”, “E2” and “U2” correspond to extrusion and upsetting passes in the first and second cycles.

Fig. 8. Textures represented by inverse pole figures for the LD after different REU passes: (a) first extrusion; (b) first upsetting; (c) second extrusion; (d) second upsetting. Contours: 1, 2, 3, 5 × random.

Fig. 9. Influence of annealing at different temperatures for 1 h on Vickers hardness of copper processed by 2 REU cycles.

Fig. 10. EBSD maps for copper processed by 2 REU passes and subsequently annealed for 1 h at different temperatures: (a) 150 °C; (b) 200 °C; (c) 250 °C and (d) 350 °C. The color code is shown in the inset in (a).

Fig. 11. Parameters of recrystallized grains in copper processed by 2 REU passes and subsequently annealed for 1 h at different temperatures: (a) area fraction fRex; (b) average grain size dRex.

Fig. 12. Textures represented by inverse pole figures for the LD in copper processed by 2 REU passes and subsequently annealed for 1 h at different temperatures: (a) 150 °C; (b) 200 °C; (c) 250 °C and (d) 350 °C. Contours: 1, 2, 3 × random.

Fig. 13. Partitioned EBSD map for the 2-cycle sample annealed at 200 °C for 1 h (the map contains the area shown in Fig. 10(b)). The LMR and HMR subsets are shown as light gray regions and dark gray regions, respectively. Recrystallized grains are shown as colored regions.

References

[1]	V.M. Segal, Mater. Sci. Eng. A, 197(1995), pp. 157-164
[2]	Y. Saito, N. Tsuji, H. Utsunomiya, T. Sakai, R.G. Hong, Scr. Mater., 39(1998), pp. 1221-1227
[3]	Y. Saito, H. Utsunomiya, N. Tsuji, T. Sakai, Acta Mater., 47(1999), pp. 579-583
[4]	M. Richert, Q. Liu, N. Hansen, Mater. Sci. Eng. A, 260(1999), pp. 275-283
[5]	M. Richert, H.P. Stüwe, M.J. Zehetbauer, J. Richert, R. Pippan, Ch. Motz, E. Schafler. Mater. Sci. Eng. A, 355(2003), pp. 180-185
[6]	S. Ferrasse, V.M. Segal, F. Alford, J. Kardokus, S. Strothers, Mater. Sci. Eng. A, 493(2008), pp. 130-140
[7]	T. Aizawa, T. Kuji, H. Nakano, J. Alloys Compd., 291(1999), pp. 248-253
[8]	L. Hu, Y. Li, E. Wang, Y. Yu, Mater. Sci. Eng. A, 422(2006), pp. 327-332
[9]	Y. Xu, L. Hu, Y. Sun, J. Jia, J. Jiang, Q. Ma. Trans, Nonferrous Metals Soc. China, 25(2015), pp. 381-388
[10]	Y. Xu, L.X. Hu, J.B. Xu, Mater. Charact., 118(2016), pp. 309-323
[11]	I. Balasundar, T. Raghu. J, Int. Mater. Form., 6(2013), pp. 289-301
[12]	I. Balasundar, K.R. Ravi, T. Raghu, Mater. Sci. Eng. A, 583(2013), pp. 114-122
[13]	B. Binesh, M. Aghaie-Khafri, Mater. Des., 95(2016), pp. 268-286
[14]	I. Balasundar, T. Raghu, J. Mech. Eng., 2(2013), pp. 130-139
[15]	L. Zaharia, R. Comaneci, R. Chelariu, D. Luca, Mater. Sci. Eng. A, 595(2014), pp. 135-142
[16]	G.L. Wu, D. Juul Jensen, Mater. Charact., 59(2008), pp. 794-800
[17]	H. Hu, Texture, 1(1974), pp. 233-238
[18]	Z.P. Luo, O.V. Mishin, Y.B. Zhang, H.W. Zhang, K. Lu, Scr. Mater., 66(2012), pp. 335-338
[19]	N. Hansen. Metall, Mater. Trans. A, 31(2001), pp. 2917-2935
[20]	O.V. Mishin, D. Juul Jensen, N. Hansen. Mater, Sci. Eng. A, 342(2003), pp. 320-328
[21]	J. Schamp, B. Verlinden, J. Van Humbeeck, Scr. Mater., 34(1996), pp. 1667-1672
[22]	G. Wang, S.D. Wu, L. Zuo, C. Esling, Z.G. Wang, G.Y. Li, Mater. Sci. Eng. A, 346(2003), pp. 83-90
[23]	Y. Estrin, N.V. Isaev, S.V. Lubenets, S.V. Malykhin, A.T. Pugachov, V.V. Pustovalov, E.N. Reshetnyak, V.S. Fomenko, L.S. Fomenko, S.E. Shumilin, M. Janecek, R.J. Hellmig, Acta Mater., 54(2006), pp. 5581-5590
[24]	F.H.Dalla Torre, A.A. Gazder, E.V. Pereloma, C.H.J. Davies. J. Mater. Sci., 42(2007), pp. 9097-9111
[25]	O.V. Mishin, A. Godfrey. Metall, Mater. Trans. A, 39(2008), pp. 2923-2930
[26]	A. Godfrey, O.V. Mishin, T.B. Yu, Mater. Sci. Forum,715-716(2012), pp. 203-210
[27]	A. Godfrey, O.V. Mishin, T.B. Yu, IOP Conf. Ser.: Mater. Sci. Eng., 89(2015), p. 012003
[28]	O.V. Mishin, J.R. Bowen, Metall. Mater. Trans. A, 40(2009), pp. 1684-1692
[29]	O.V. Mishin, J.R. Bowen, A. Godfrey, Mater. Sci. Forum,715-716(2012), pp. 825-830
[30]	G. Gottstein, Acta Metall., 32(1994), pp. 1117-1138