Effect of Stacking Fault Energy on the Grain Structure Evolution of FCC Metals During Friction Stir Welding

doi:10.1007/s40195-020-01064-6

Abstract

Abstract:

The effect of stacking fault energy (SFE) on the grain structure evolution of face-centered cubic metals during friction stir welding was investigated by using pure aluminum, pure copper and Cu-30Zn alloy as experiment materials. Tool “stop action” and rapid cooling were employed to “freeze” the microstructure of the flowing materials around the tool. Marker materials were used to show the streamline of the material flow. The microstructures of the three materials at different welding stages were contrastively studied by the electron backscatter diffraction technique. The results show that at the material flow stage, as the SFE decreases, the grain structure evolution changes from the continuous dynamic recrystallization to discontinuous dynamic recrystallization, and further to the dynamic equilibrium between the annealing twinning due to thermally activated grain boundary migration and the twin destruction during the plastic deformation. Owing to different grain structure evolution mechanisms, the grain structure at the end of the material flow is greatly different. Especially in copper, a lot of dislocations remain, which gives rise to the static recrystallization occurring during the subsequent cooling stage.

Key words: Stacking fault energy, Friction stir welding, Microstructure evolution, Face-centered cubic (FCC) metal, Electron backscattered diffraction (EBSD), Recrystallization

Xiaochao Liu, Yufeng Sun, Tomoya Nagira, Kohsaku Ushioda, Hidetoshi Fujii. Effect of Stacking Fault Energy on the Grain Structure Evolution of FCC Metals During Friction Stir Welding[J]. Acta Metallurgica Sinica (English Letters), 2020, 33(7): 1001-1012.

Figures/Tables 8

Fig. 1 Schematic of the experiment: a welding procedure; b EBSD measured positions

Fig. 2 Microstructural features of the base materials: a-c EBSD grain boundary maps; a pure aluminum; b pure copper; c Cu-30Zn

Fig. 3 Microstructural features at the deformation beginning position (P1): a1-c1 EBSD grain boundary maps; a2-c2 the corresponding KAM maps; a1,2 pure aluminum; b1,2 pure copper; c1,2 Cu-30Zn

Fig. 4 Microstructural features at the recrystallization beginning position (P2): a1-c1 EBSD grain boundary maps; a2-c2 the corresponding KAM maps; a1,2 pure aluminum; b1,2 pure copper; c1,2 Cu-30Zn

Fig. 5 Microstructural features at the high-speed flowing stage (P3): a1-c1 EBSD grain boundary maps; a2-c2 the corresponding KAM maps; a1,2 pure aluminum; b1,2 pure copper; c1,2 Cu-30Zn

Fig. 6 Dynamic equilibrium between the annealing twinning due to the thermally activated grain boundary migration and the twin destruction due to the continuous deformation during the material flow in the FSW of Cu-30Zn: a EBSD IQ map; b the corresponding misorientation angle distribution; c the IPF and KAM maps of the region c selected in a; d the IPF and KAM maps of the region d selected in a. Note: in the IQ and IPF maps, the black line donates HABs and the red line denotes ∑3 TBs

Fig. 7 Microstructural features at the material flow ending position (P4) before a12, c1,2, e1,2 and after a short-time annealing b1,2, d1,2, f1,2: a1-f1 EBSD grain boundary maps and KAM maps; a2-f2 the corresponding ODF maps; a1,2, b1,2 pure aluminum; c1,2, d1,2 pure copper; e1,2, f1,2 Cu-30Zn

Fig. 8 Schematic of grain structure evolution during the FSW of metals with different SFE

References 41

[1]	W.M. Thomas, E.D. Nicholas, J.C. Needham, M.G. Murch, P. Templesmith, C.J. Dawes, Friction Stir Butt Welding, GB Patent 9125978.8, International Patent PCT/GB92/02203, 1991
[2]	G.K. Padhy, C.S. Wu, S. Gao, J. Mater. Sci. Technol. 34, 1 (2018)
[3]	C.S. Wu, H. Su, L. Shi, Acta Metall. Sin. 54, 265 (2017). (in Chinese)
[4]	G. Chen, S. Zhang, Y. Zhu, C. Yang, Q. Shi, Acta Metall. Sin. Engl. Lett. 33, 3 (2020)
[5]	N. Xu, R.N. Feng, W.F. Guo, Q.N. Song, Y.F. Bao, Acta Metall. Sin. Engl. Lett. 33, 319 (2020)
[6]	Z. Shen, Y. Ding, A.P. Gerlich, Crit. Rev. Solid State Mater. Sci. (2019). https://doi.org/10.1080/10408436.2019.1671799
[7]	Y. Chen, H. Wang, X. Wang, H. Ding, J. Zhao, F. Zhang, Z. Ren, Mater. Sci. Eng. A 739, 272 (2019)
[8]	Z.Y. Ma, A.H. Feng, D.L. Chen, J. Shen, Crit. Rev. Solid State Mater. Sci. 43, 269 (2018)
[9]	B. He, L. Cui, D. Wang, H.J. Li, C.X. Liu, Acta Metall. Sin. Engl. Lett. 33, 135 (2020)
[10]	R. Nandan, T. DebRoy, H.K.D.H. Bhadeshia, Prog. Mater. Sci. 53, 980 (2008)
[11]	W.D. Callister, Fundamentals of Materials Science and Engineering (Wiley, London, 2000) URL PMID
[12]	F.J. Humphreys, M. Hatherly, Recrystallization and Related Annealing Phenomena (Elsevier, Amsterdam, 2012)
[13]	P.B. Prangnell, C.P. Heason, Acta Mater. 53, 3179 (2005)
[14]	S. Mironov, Y.S. Sato, H. Kokawa, Acta Mater. 56, 2602 (2008)
[15]	S. Mironov, Y.S. Sato, H. Kokawa, Acta Mater. 57, 4519 (2009)
[16]	W. Wang, P. Han, P. Peng, T. Zhang, Q. Liu, S.N. Yuan, L.Y. Huang, H.L. Yu, K. Qiao, K.S. Wang, Acta Metall. Sin. Engl. Lett. 33, 43 (2020)
[17]	K.V. Jata, S.L. Semiatin, Scr. Mater. 8, 743 (2000)
[18]	J.Q. Su, T.W. Nelson, C.J. Sterling, Mater. Sci. Eng. A 405, 277 (2005)
[19]	R.W. Fonda, J.F. Bingert, K.J. Colligan, Scr. Mater. 51, 243 (2004)
[20]	Y. Huang, Y. Xie, X. Meng, J. Li, Mater. Sci. Eng. A 740, 211 (2019)
[21]	S. Mironov, K. Inagaki, Y.S. Sato, H. Kokawa, Philos. Mag. 95, 367 (2015)
[22]	S. Mironov, K. Inagaki, Y.S. Sato, H. Kokawa, Philos. Mag. 94, 3137 (2014)
[23]	X.C. Liu, Y.F. Sun, Y. Morisada, H. Fujii, J. Mater. Process. Technol. 252, 643 (2018)
[24]	X.C. Liu, Y.F. Sun, T. Nagira, K. Ushioda, H. Fujii, Sci. Technol. Weld. Join. 24, 352 (2019)
[25]	X.C. Liu, Y.F. Sun, T. Nagira, K. Ushioda, H. Fujii, J. Mater. Sci. Technol. 35, 1412 (2019)
[26]	X.C. Liu, Y.F. Sun, T. Nagira, K. Ushioda, H. Fujii, Materialia 6, 100302 (2019)
[27]	X.C. Liu, Y.F. Sun, H. Fujii, Mater. Des. 129, 151 (2017)
[28]	X.C. Liu, Y.F. Sun, T. Nagira, H. Fujii, Mater. Character. 137, 24 (2018)
[29]	X.C. Liu, Y.F. Sun, T. Nagira, K. Ushioda, H. Fujii, J. Mater. Sci. 53, 10423 (2018)
[30]	D. Yi, S. Mironov, Y.S. Sato, H. Kokawa, Philos. Mag. 96, 1965 (2016)
[31]	T. Hasegawa, U.F. Kocks, Acta Metall. 27, 1705 (1979)
[32]	T. Hasegawa, U.F. Kocks, H.J. McQueen, E. Evangelista, J. Phys. B 38, 359 (1988)
[33]	S. Gourdet, F. Montheillet, Mater. Sci. Eng. A 283, 274 (2000)
[34]	M.R. Barnett, F. Montheillet, Acta Mater. 50, 2285 (2002)
[35]	S. Mironov, K. Inagaki, Y.S. Sato, H. Kokawa, Metall. Mater. Trans. A 46, 783 (2015)
[36]	D.G. Cram, H.S. Zurob, Y.J.M. Brechet, C.R. Hutchinson, Acta Mater. 57, 5218 (2009)
[37]	A. Heidarzadeh, T. Saeid, V. Klemm, A. Chabok, Y. Pei, Mater. Des. 162, 185 (2019)
[38]	Y. Jin, Annealing Twin Formation Mechanism, Diss. Ecole ationale Supérieure des Mines de Paris (2014)
[39]	N. Xu, R. Ueji, H. Fujii, J. Mater. Process. Technol. 232, 90 (2016)
[40]	T. Nagira, X.C. Liu, K. Ushioda, Y. Iwamoto, G. Ano, H. Fujii, Sci. Technol. Weld. Join. 24, 644 (2019)
[41]	J. Pelleg, Mechanical Properties of Materials (Springer, Beer Sheva, 2013)