Effects of Passes on Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy During Multidirectional Forging

doi:10.1007/s40195-018-0769-6

Abstract

Abstract:

The multidirectional forging (MDF) process was conducted at temperature of 753 K to optimize the mechanical properties of as-homogenized Mg-13Gd-4Y-2Zn-0.6Zr alloy containing long-period stacking ordered phase. The effects of MDF passes on microstructure evolution and mechanical properties were also investigated. The results show that both the volume fraction of dynamic recrystallization (DRX) grains and mechanical properties of the deformed alloy enhanced with MDF passes increasing till seven passes. The average grain size decreased from 76 to 2.24 μm after seven passes, while the average grain size increased to 7.12 μm after nine passes. The microstructure after seven passes demonstrated randomly oriented fine DRX grains and larger basal (0001)<11$bar{2}$0> Schmid factor of 0.31. The superior mechanical properties at room temperature (RT) with ultimate tensile strength (UTS) of 416 MPa and fracture elongation of 4.12% can be obtained after seven passes. The mechanical properties at RT after nine passes are inferior to those after seven passes due to the coarsening of DRX grains, which can be ascribed to the static recovery resulting from the repeated heating at the interval of MDF passes. The elevated temperature mechanical properties of the deformed alloy after seven passes and nine passes were investigated. When test temperature was below 523 K, the elevated temperature tensile yield strength and UTS after seven passes are superior to those after nine passes, while they are inferior to that after nine passes as temperature exceeds 523 K.

Key words: Mg-Gd-Y-Zn-Zr, Multidirectional forging, Microstructure, Mechanical properties

Bing Li, Bu-Gang Teng, De-Gao Luo. Effects of Passes on Microstructure Evolution and Mechanical Properties of Mg-Gd-Y-Zn-Zr Alloy During Multidirectional Forging[J]. Acta Metallurgica Sinica (English Letters), 2018, 31(10): 1009-1018.

Figures/Tables 13

Table 1 Nominal composition of Mg-13Gd-4Y-2Zn-0.6Zr alloy (wt%)

Element	Gd	Y	Zn	Zr	Cu	Fe	Si	Mg
Content	12.99	4.00	2.00	0.60	0.0060	0.0014	0.0042	Bal.

Fig. 1 Schematic diagram of multidirectional forging process

Fig. 2 The location for a tensile test at RT and ET, b microstructure observation

Fig. 3 Optical microstructure of the as-received Mg-Gd-Y-Zn-Zr alloy a at low magnification, b at high magnification

Fig. 4 Optical microstructures of as-homogenized Mg-Gd-Y-Zn-Zr alloy a at low magnification, b at high magnification

Fig. 5 XRD patterns of as-cast, as-homogenized and deformed alloy after seven passes: a the whole section, b the amplified part section of XRD patterns

Fig. 6 Microstructures of deformed alloy after: a three passes, b five passes, c seven passes, d nine passes during MDF

Fig. 7 IPF maps a-d, pole figures e-h and basal (0001) Schmid factor i-l distribution of the samples after different MDF passes: a, e, i three passes, b, f, j five passes, c, g, k seven passes, d, h, l nine passes

Fig. 8 After five-pass MDF a the IPF maps, b misorientations measured along the black line in primary grain

Fig. 9 Distributions of grain boundary orientation after a three-pass, b five-pass, c seven-pass, d nine-pass MDF, e misorientation variation for different types of boundaries after different passes

Fig. 10 Mechanical properties of deformed alloy with different MDF passes

Fig. 11 Elevated temperature mechanical properties of the deformed alloy after a seven passes, b nine passes

Table 2 Elevated temperature mechanical properties of deformed alloy after seven passes and nine passes

MDF passes	Tensile temperature (K)	Tensile yield strength (0.2%) (MPa)	Ultimate tensile strength (MPa)	Elongation (%)
Seven passes	473	292	390	12.7
	523	200	263	44.7
	573	92	147	142
Nine passes	473	267	349	11.9
	523	204	279	27.3
	573	121	174	80.3

References

[1]	C. Wang, H. Ding, B.S. Wang, K. Wang, J.J. Shi, J.F. Chen, Acta Metall. Sin. (Engl. Lett.) 30, 921(2017)
[2]	H. Friedrich, S. Shumann, J. Mater. Process. Technol. 117, 276(2001)
[3]	Q.F. Zhu, G.S. Wang, E.G. Zhang, F.Z. Liu, Z.Q. Zhang, J.Z. Cui, Acta Metall. Sin. (Engl. Lett.) 30, 941(2017)
[4]	D. Sarker, J. Friedman, D.L. Chen, J. Mater. Sci. Technol. 31, 264(2015)
[5]	L. Wang, Y.Q. Zhao, H.M. Chen, J. Zhang, Y.D. Liu, Y.N. Wang, Acta Metall. Sin. (Engl. Lett.) 31, 63(2018)
[6]	X.S. Xia, K. Zhang, X.G. Li, M.L. Ma, Y.J. Li, Mater. Des. 44, 521(2013)
[7]	B.N. Du, Z.Y. Hu, L.Y. Sheng, D.K. Xu, Y.F. Zheng, T.F. Xi, Acta Metall. Sin. (Engl. Lett.) 31, 351(2018)
[8]	X.J. Wang, D.K. Xu, R.Z. Wu, X.B. Chen, Q.M. Peng, L. Jin, Y.C. Xin, Z.Q. Zhang, Y. Liu, X.H. Chen, G. Chen, K.K. Deng, H.Y. Wang, J. Mater. Sci. Technol. 34, 245(2018)
[9]	S.M. He, X.Q. Zeng, L.M. Peng, X. Gao, J.F. Nie, W.J. Ding, J. Alloys Compd. 427, 316(2007)
[10]	X.M. Zong, D. Wang, W. Liu, K.B. Nie, C.X. Xu, J.S. Zhang, Acta Metall. Sin. (Engl. Lett.) 29, 32(2016)
[11]	Z. Su, C. Liu, Y. Wan, Mater. Des. 45, 466(2013)
[12]	C. Xu, M.Y. Zheng, S.W. Xu, K. Wu, E.D. Wang, S. Kamado, G.J. Wang, X.Y. Lv, Mater. Sci. Eng. A 547, 93 (2012)
[13]	S. Zhang, G.Y. Yuan, C. Lu, W.J. Ding, J. Alloys Compd. 509, 3515(2011)
[14]	M. Yamasaki, M. Sasaki, M. Nishijima, K. Hiraga, Y. Kawamura, Acta Mater. 55, 6798(2007)
[15]	Q. Yang, B.L. Xiao, D. Wang, M.Y. Zheng, Z.Y. Ma, Mater. Sci. Eng. A 626, 275 (2015)
[16]	K. Hagihara, A. Kinoshita, Y. Sugino, M. Yamasaki, Y. Kawamura, H.Y. Yasuda, Y. Umakoshi, Acta Mater. 58, 6282(2010)
[17]	J. Yang, J. Peng, M. Li, E.A. Nyberg, F.S. Pan, Acta Metall. Sin. (Engl. Lett.) 30, 53(2017)
[18]	K. Hagihara, N. Yokotani, Y. Umakoshi, Intermetallics 18, 267 (2010)
[19]	M. Yamasaki, K. Hagihara, S. Inoue, J.P. Hadorn, Y. Kawamura, Acta Mater. 61, 2065 (2013)
[20]	W.T. Sun, C. Xu, X.G. Qiao, M.Y. Zheng, S. Kamado, N. Gao, M.J. Starink, J. Alloys Compd. 700, 312(2007)
[21]	W. Liu, J.S. Zhang, C.X. Xu, X.M. Zong, W. Zhu, Q.Q. Ma, Metals 52, 13271 (2017)
[22]	H. Huang, Mater. Sci. Eng. A 674, 52 (2016)
[23]	X.S. Xia, Q. Chen, Z.D. Zhao, M.L. Ma, X.G. Li, K. Zhang, J. Alloys Compd. 623, 62(2015)
[24]	Y.Z. Wu, H.G. Yan, J.H. Chen, Y.G. Du, S.Q. Zhu, B. Su, Mater. Sci. Eng. A 556, 164 (2012)
[25]	L.C. Tang, C.M. Liu, Z.Y. Chen, D.W. Ji, H.C. Xiao, Mater. Des. 50, 587(2013)
[26]	Q.F. Zhu, L. Li, C.Y. Ban, Z.H. Zhao, Y.B. Zuo, J.Z. Cui, Trans. Nonferrous Met. Soc. China 24, 1301 (2014)
[27]	Y. Nakao, H. Miura, Mater. Sci. Eng. A 528, 1310 (2011)
[28]	C. Xu, M.Y. Zheng, Y.Q. Chi, X.J. Chen, K. Wu, G.H. Fan, E.D. Wang, S.W. Xu, S. Kamado, G.J. Wang, X.Y. Lv, Mater. Sci. Eng. A 549, 128 (2012)
[29]	X.J. Zhou, C.M. Liu, Y.H. Gao, S.N. Jiang, W.H. Liu, L.W. Lu, J. Alloys Compd. 724, 528(2017)
[30]	X.J. Zhou, C.M. Liu, Y.H. Gao, S.N. Jiang, X.Z. Han, Z.Y. Chen, Metall. Mater. Trans. A 48, 3060 (2017)
[31]	H. Liu, J. Ju, X.W. Yang, J.L. Yan, D. Song, J.H. Jiang, A.B. Ma, J. Alloys Compd. 704, 509(2017)
[32]	M. Matsuda, S. Ii, Y. Kawamura, Y. Ikuhara, M. Nishida, Mater. Sci. Eng. A 386, 447 (2004)
[33]	C. Xu, T. Nakata, X. Qiao, M. Zheng, K. Wu, S. Kamado, Sci. Rep. 7, 40486(2017)
[34]	Y. Meng, Q. Chen, S. Sugiyama, J. Yanagimoto, J. Mater. Process. Technol. 247, 192(2017)
[35]	H. Xiao, B. Tang, C. Liu, Y. Gao, S. Yu, S. Jiang,Mater. Sci. Eng. A 645, 241 (2015)
[36]	Y.M. Wang, E. Ma, Acta Mater. 52, 1699(2004)