Grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

doi:10.1016/j.jmst.2021.02.052

Abstract

Abstract:

We elucidate the effect of lanthanum (La) on the grain refinement of Mg-3Sn-1Mn alloy during accumulative hot rolling. The lath-shaped Mg₂Sn phase in the Mg-3Sn-1Mn alloy is firstly broken and spheroidized, and then the size increases and coarsens with the increase of rolling reduction, most of Mg₂Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped MgSnLa compound in Mg-3Sn-1Mn-1La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys become fine through dynamic recrystallization (DRX), though the grain refinement of Mg-3Sn-1Mn-1La alloy is better compared to the Mg-3Sn-1Mn alloy. A large number of uniformly distributed spherical MgSnLa compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRX increases and promotes the formation of deformation bands and more twins, providing the sites for DRX nucleation and growth.

Key words: Mg alloy, Grain refinement, Dynamic recrystallization, Accumulative hot rolling

Z.Y. Zhao, R.G. Guan, Y.F. Shen, P.K. Bai. Grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling[J]. J. Mater. Sci. Technol., 2021, 91: 251-261.

Figures/Tables 11

Fig. 1. Optical images of the Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys with different AHR reductions: (a-c) Mg-3Sn-1Mn alloy after rolling with a reduction of 0, 71%, and 93%, for comparison; (a1-c1) morphologies of Mg-3Sn-1Mn-1La alloy after the identical reductions.

Fig. 2. SEM images of the Mg-3Sn-1Mn (a-d) and Mg-3Sn-1Mn-1La (a1-d1) alloys after different AHR passes with a rolling reduction of 0, 43%, 71%, and 93%, respectively, EDS of position A and B showing the Mg2Sn (e) and MgSnLa (e1).

Fig. 3. TEM images of the Mg-3Sn-1Mn (a-d), and Mg-3Sn-1Mn-1La (a1-d1) alloys during the AHR passes with a thickness reduction of 0, 43%, 71%, and 93%, respectively, EDS of position C and D showing the Mg2Sn (e) and MgSnLa (e1).

Fig. 4. EBSD inverse pole figures (IPFs) (a, b) and grain boundary maps (a1, b1) of the as-prepared Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys. HAGBs and LAGBs are indicated by black and green in the grain boundary maps.

Fig. 5. EBSD IPFs of the Mg-3Sn-1Mn (a, b, c) and Mg-3Sn-1Mn-1La (a1, b1, c1) alloys after hot rolling with various thickness reductions of 14%, 43%, and 93%, respectively.

Fig. 6. Grain boundary maps (HAGBs in black and LAGBs in green) of the Mg-3Sn-1Mn (a, b, c) and Mg-3Sn-1Mn-1La (a1, b1, c1) alloys after hot rolling with various thickness reductions of 14%, 43%, and 93%, respectively.

Fig. 7. Microstructure evolution with the different thickness reductions in the AHR processes of the Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys.

Fig. 8. KAM maps and distributions of the Mg-3Sn-1Mn (a, a1) and Mg-3Sn-1Mn-1La (b, b1) alloys after AHR with a thickness reduction of 14%, and the corresponding results for the specimens with a thickness reduction of 93% are shown in (c, c1) and (d, d1) for two alloys.

Table 1 GND density in the Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys after the AHR processing with different thickness reduction (ɛ).

Alloy	GND density
Alloy	ɛ = 14%	ɛ = 93%
Mg-3Sn-1Mn	1.7b × 10¹⁴	9.7b × 10¹³
Mg-3Sn-1Mn-1La	2.4b × 10¹⁴	5.8b × 10¹³

Fig. 9. TEM images of the MgSnLa compounds pin the (sub) grain boundary (thickness reduction of 93%) (a), and deformation twins (thickness reduction of 43%) (b) as well as lattice distortion (c) after the AHR processing Mg-3Sn-1Mn-1La alloy (thickness reduction of 43%). (d) Schematic illustration indicates the dislocations tangles bulge toward outside of twin boundaries to form LAGBs, which subsequently transforms to HAGBs.

Fig. 10. Grain boundary maps of Mg-3Sn-1Mn (a) and Mg-3Sn-1Mn-1La (b) alloys after hot rolling with an identical thickness reduction of 14% (HAGBs in black and twin boundaries in red).

References 50

[1]	X. Yang, J. Liu, Z. Wang, X. Lin, F. Liu, W. Huang, E. Liang, Mater. Sci. Eng. A 774 (2020) 138942.
[2]	F. Zhang, Z. Liu, M. Yang, G. Su, R. Zhao, P. Mao, F. Wang, S. Sun, Mater. Sci. Eng. A 771 (2020) 138571.
[3]	H. Tang, F. Wang, D. Li, X. Gu, Y. Fan, Mater. Lett. 264(2020) 127285.
[4]	Z. Zhao, P. Bai, W. Du, B. Liu, D. Pan, R. Das, C. Liu, Z. Guo, Carbon N Y 170 (2020) 302-326.
[5]	A. Zhang, R. Kang, L. Wu, H. Pan, H. Xie, Q. Huang, Y. Liu, Z. Ai, L. Ma, Y. Ren, G. Qin, Mater. Sci. Eng. A 754 (2019) 269-274.
[6]	C. Zhao, X. Chen, F. Pan, S. Gao, D. Zhao, X. Liu, Mater. Sci. Eng. A 713 (2018) 244-252.
[7]	Y.Z. Du, X.G. Qiao, M.Y. Zheng, K. Wu, S.W. Xu, Mater. Des. 85(2015) 549-557.
[8]	J.B. Zhang, L.B. Tong, C. Xu, Z.H. Jiang, L.R. Cheng, S. Kamado, H.J. Zhang, Mater. Sci. Eng. A 708 (2017) 11-20.
[9]	H. Zengin, Y. Turen, Mater. Chem. Phys. 214(2018) 421-430.
[10]	Q. Luo, C. Zhai, Q. Gu, W. Zhu, Q. Li, J Alloys Compd 814 (2020) 152297.
[11]	Q. Luo, Y. Guo, B. Liu, Y. Feng, J. Zhang, Q. Li, K. Chou. J. Mater. Sci. Technol. 44(2020) 171-190.
[12]	Y. Wang, J. Fu, Y. Yang, Trans. Nonferrous Met. Soc. China 22 (2012) 1322-1328.
[13]	X. Chen, D. Zhang, J. Xu, J. Feng, Y. Zhao, B. Jiang, F. Pan. J. Alloys Compd. 850(2021) 156711.
[14]	X. Gu, W. Cheng, S. Cheng, Y. Liu, Z. Wang, H. Yu, Z. Cui, L. Wang, H. Wang. J. Mater. Sci. Technol. 60(2021) 77-89.
[15]	R. Guan, Z. Zhao, H. Zhang, T. Cui, C.S. Lee, Mater. Sci. Eng. A 559 (2013) 194-200.
[16]	F. Pan, M. Yang, Mater. Sci. Eng. A 528 (2011) 4973-4981.
[17]	L. Hou, Z. Li, H. Zhao, Y. Pan, S. Pavlinich, X. Liu, X. Li, Y. Zheng, L. Li. J. Mater. Sci. Technol. 32(2016) 874-882.
[18]	P. Cheng, Y. Zhao, R. Lu, H. Hou, Z. Bu, F. Yan, Mater. Sci. Eng. A 708 (2017) 482-4 91.
[19]	H. Liao, J. Kim, J. Lv, B. Jiang, X. Chen, F. Pan. J. Alloys Compd. 831(2020) 154873.
[20]	H. Liao, J. Kim, T. Lee, J. Song, J. Peng, B. Jiang, F. Pan. J. Magnes. Alloy. 8(2020) 1120-1127.
[21]	X. Wei, L. Jin, C. Liu, F. Wang, S. Dong, J. Dong, Mater. Sci. Eng. A 802 (2021) 140674.
[22]	X. Zhou, W. Xiong, G. Zeng, H. Xiao, J. Zhang, X. Lu, X. Chen, Mater. Sci. Eng. A(2020) 140596.
[23]	B. Li, B. Teng, E. Wang, Mater. Sci. Eng. A 765 (2019) 138317.
[24]	M.M. Castro, S. Sabbaghianrad, P.H.R. Pereira, E.M. Mazzer, A. Isaac, T.G. Lang- don, R.B. Figueiredo , J. Alloys Compd. 804(2019) 421-426.
[25]	M.A. Salevati, F. Akbaripanah, R. Mahmudi, K.H. Fekete, A. Heczel, J. Gubicza, Mater. Sci. Eng. A 776 (2020) 139002.
[26]	B. Omranpour, Y. Ivanisenko, R. Kulagin, L. Kommel, E.G. Sanchez, D. Nug- manov, T. Scherer, A. Heczel, J. Gubicza, Mater. Sci. Eng. A 762 (2019) 138074.
[27]	D. Zhao, X. Chen, X. Wang, F. Pan, Mater. Sci. Eng. A 773 (2020) 138741.
[28]	H. Esmaeilpour, A. Zarei-Hanzaki, N. Eftekhari, H.R. Abedi, M.R. Ghandehari Ferdowsi, Mater. Sci. Eng. A 778 (2020) 139.
[29]	X. An, Y. Tian, H. Wang, Y. Shen, Z. Wang, Adv. Eng. Mater. 21(2019) 1900132.
[30]	J. Go, J.U. Lee, H. Yu, S.H. Park. J. Mater. Sci. Technol. 44(2020) 62-75.
[31]	Y. Meng, J. Yu, K. Liu, H. Yu, F. Zhang, Y. Wu, Z. Zhang, N. Luo, H. Wang. J. Alloys Compd. 828(2020) 154454.
[32]	M.M. Hoseini-Athar, R. Mahmudi, R. Prasath Babu, P. Hedström. J. Alloys Compd. 806(2019) 1200-1206.
[33]	Q. Wu, H. Yan, J. Chen, W. Xia, M. Song, B. Su, Mater. Charact. 160(2020) 110131.
[34]	C.Q. Liu, H.W. Chen, H. Liu, X.J. Zhao, J.F. Nie, Acta Mater 144 (2018) 590-600.
[35]	R.G. Guan, Y.F. Shen, Z.Y. Zhao, R.D.K. Misra , Sci.Rep. 6(2016) 23154.
[36]	Z. Zhao, P. Bai, R. Guan, V. Murugadoss, H. Liu, X. Wang, Z. Guo, Mater. Sci. Eng. A 734 (2018) 200-209.
[37]	Q. Luo, J. Li, B. Li, B. Liu, H. Shao, Q. Li. J. Magnes. Alloy. 7(2019) 58-71.
[38]	Y. Guo, B. Liu, W. Xie, Q. Luo, Q. Li, Scr. Mater. 193(2021) 127-131.
[39]	Y. Li, B. Hu, B. Liu, A. Nie, Q. Gu, J. Wang, Q. Li, Acta Mater 187 (2020) 51-65.
[40]	J. Xu, Y. Li, B. Hu, Y. Jiang, Q. Li. J. Mater. Sci. 54(2019) 14561-14576.
[41]	Y. Pang, D. Sun, Q. Gu, K.-.C. Chou, X. Wang, Q. Li, Cryst. Growth Des. 16(2016) 2404-2415.
[42]	L.S. Toth, C.F. Gu, B. Beausir, J.J. Fundenberger, M. Hoffman, Acta Mater. 117(2016) 35-42.
[43]	J.H. Lee, J.U. Lee, S.-.H. Kim, S.W. Song, C.S. Lee, S.H. Park, J. Mater. Sci. Technol. 34(2018) 1747-1755.
[44]	L.Y. Zhao, H. Yan, R.S. Chen, E.-.H. Han, J.Mater. Sci. Technol. 60(2021) 162-167.
[45]	L.P. Kubin, A. Mortensen, Scr. Mater. 48(2003) 119-125.
[46]	Z. Yan, D. Wang, X. He, W. Wang, H. Zhang, P. Dong, C. Li, Y. Li, J. Zhou, Z. Liu, L. Sun, Mater. Sci. Eng. A 723 (2018) 212-220.
[47]	H. Gao, Y. Huang, W.D. Nix, J.W. Hutchinson, J. Mech. Phys. Solids 47 (1999) 1239-1263.
[48]	Y.F. Shen, N. Jia, R.D.K. Misra, L. Zuo, Acta Mater 103 (2016) 229-242.
[49]	Y.F. Shen, Y.D. Wang, X.P. Liu, X. Sun, R.L. Peng, S.Y. Zhang, L. Zuo, P.K. Liaw, Acta Mater. 61(2013) 6093-6106.
[50]	M.J. Wang, C.Y. Sun, M.W. Fu, Z.L. Liu, L.Y. Qian. J. Alloys Compd. 820(2020) 153325.