Finite element modelling on microstructure evolution during multi-pass hot compression for AZ31 alloys using incremental method

doi:10.1016/j.jmst.2017.10.008

Abstract

Abstract:

Based on the principle of piecewise linearization, the incremental forms of microstructure evolution models were integrated into the thermo-mechanical coupled finite element (FE) model to simulate non-linear microstructure evolution during multi-pass hot deformation. This is an unsteady-state deformation where dynamic recrystallization (DRX), meta-dynamic recrystallization (MDRX), static recrystallization (SRX) and grain growth (GG) take place during hot deformation or deformation interval. The distributions of deformation and microstructure for cylindrical AZ31 sample during single-pass and double-pass hot compressions were quantitatively calculated and compared with the metallographic observation. It is shown that both the deformation and microstructure are non-uniformly distributed due to the presence of friction between the die and the flat end of sample. The average grain size and its standard deviation under the double-pass hot compression are slightly smaller than those under single-pass compression. The simulated average grain sizes agree well with the experiments, which validates that the developed FE model on the basis of incremental forms of microstructure evolution models is reasonable.

Key words: Incremental method, Microstructure evolution, Multi-pass hot compression, Finite element method, Magnesium alloys

Jin Zhaoyang, Yin Kai, Yan Kai, Wu Defeng, Liu Juan, Cui Zhenshan. Finite element modelling on microstructure evolution during multi-pass hot compression for AZ31 alloys using incremental method[J]. J. Mater. Sci. Technol., 2017, 33(11): 1255-1262.

Figures/Tables 12

Fig. 1. Initial microstructure of as-extruded AZ31 alloy.

Fig. 2. Flowchart of microstructure evolution subroutine for multi-pass deformation.

Table 1 Variance of thermal parameters of AZ31 with temperature [16].

Temperature (°C)	Coefficient of thermal expansion (10^-6 K^-1)	Specific heat (10³J/(kg °C))
250	29.7	1.19
300	30.6	1.21
350	31.55	1.26
400	32.5	1.30

Table 2 Values of material parameters of AZ31 [16].

Poisson ratio	Elastic modulus (GPa)	Thermal conductivity (W/(m K))		Density (g/cm²)	Friction coefficient	Heat transfer coefficient (sample and air) (W/(m² °C))		Heat transfer coefficient (sample and die) (W/(m² °C))
0.35	45.0	154	1.77		0.3	20	3000

Fig. 3. Experimental procedure for two-pass hot compression test.

Fig. 4. Effective strain distribution at height reduction of 8.26 mm for (a) double-pass and (b) single-pass hot compression.

Fig. 5. Variance of effective strain with stroke at Points A, C and D under single-pass and double- pass hot compression (a) diagrammatic of characteristic points and (b) variation of effective strain with stroke.

Fig. 6. Variance of DRX volume fraction with stroke at Points A, C and D under single- pass tests.

Fig. 7. Time dependence of DRX fraction and MDRX fraction at Points A, C and D under double-pass deformation.

Fig. 8. Variance of average grain size with stroke at Points A, C and D under single-pass and double-pass hot compression.

Fig. 9. Grain size distribution during inter-pass time after holding for (a) 2 s and (b) 6 s.

Fig. 10. Comparison between simulated average grain size distributions (a1, a2) and metallographic observations at Point A (b1, b2) and Point C (c1, c2) under single-pass (denoted by 1) and double-pass (denoted by 2) hot compression.

References

[1]	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. (2017), .
[2]	Y.G. Ko, J.S. Lee, Loorentz, Mater. Sci. Technol.-Lond. 29 (5) (2013) 553-558.
[3]	M.M. Amrei, Y. Verreman, F. Bridier, D. Thibault, P. Bocher, Metallogr. Microstruct. Anal. 4(2015) 207-218.
[4]	D.X. Wen, Y.C. Lin, Y. Zhou, Vacuum 141 (2017) 316-327.
[5]	Y.X. Liu, Y.C. Lin, Y. Zhou, Mater. Sci. Eng. A 691 (2017) 88-99.
[6]	Z.Y. Jin, D.H. Yu, X.T. Wu, K. Yin, K. Yan, J. Mater. Sci. Technol. 32(2016) 1260-1266.
[7]	H. Liu, Z.J. Cheng, K. Yan, J.L. Yan, J. Bai, J.H. Jiang, A. Ma, J. Mater. Sci. Technol. 32(2016) 1274-1281.
[8]	G. Faraji, P. Yavari, S. Aghdamifar, M.M. Mashhadi, J. Mater. Sci. Technol. 30(2014) 134-138.
[9]	L. Hou, T. Wang, R. Wu, J.H. Zhang, M.L. Zhang, A.P. Dong, B.D. Sun, S. Betsofen, B. Krit, J. Mater. Sci. Technol. (2017), .
[10]	L. Yang, Q.X. Liu, Y.C. Zhou, W.G. Mao, C. Lu, J. Mater. Sci. Technol. 30 (4) (2014) 371-380.
[11]	W.Z. Tang, L. Yang, W. Zhu, Y.C. Zhou, J.W. Guo, C. Lu, J. Mater. Sci. Technol. 32(2016) 452-458.
[12]	K.H. Jung, H.W. Lee, Y.T. Im, Mater. Sci. Eng. A 519 (2009) 94-101.
[13]	D.S. Qian, Y.Y. Peng, Mater. Eng. Perform. 24(2015) 1906-1917.
[14]	H. Jiang, L. Yang, J.X. Dong, M.C. Zhang, Z.H. Yao, Mater. Des. 104(2016) 162-173.
[15]	W.F. Shen, C. Zhang, L.W. Zhang, Y.N. Xia, J. Mater. Res. 32 (3) (2017) 656-665.
[16]	Z.Y. Jin, N.N. Li, K.Y. Li, K. Yan, Z.S. Cui, J. Shanghai Jiao Tong Univ. 51 (1) (2017) 119-123, in Chinese.
[17]	J. Liu, Z. Cui, L. Ruan, Mater. Sci. Eng. A 529 (1) (2011) 300-310.
[18]	G.Z. Quan, Y. Shia, Y.X. Wang, B.S. Kang, T.W. Ku, W.J. Song, Mater. Sci. Eng. A 528 (2011) 8051-8059.
[19]	M. Ullmann, M. Graf, R. Kawalla, Mater. Today 2S (2015) S212-S218.
[20]	A.G. Beer, M.R. Barnett, Scripta Mater. 61 (10) (2009) 1097-1100.
[21]	Z.T. Wang, L.Y. Wang, L.Z. Liu, Indian J. Mater. Sci. 36(2015) 222-227.
[22]	G.D. Zhao, The Mechancis Behavior and Dymanic Recrystallization in Hot Deformation of AZ31 Alloy, Chongqing University, 2005, MSC, Thesis (in Chinese).
[23]	I. Schindler, P. Kawulok, E. Hadasik, J. Mater. Eng. Perform. 22 (3) (2013) 890-897.