Coherent interface strengthening of ultrahigh pressure heat-treated Mg-Li-Y alloys

doi:10.1016/j.jmst.2020.02.039

Abstract

Abstract:

Achieving good strength-ductility of Mg alloys has always been a crucial issue for the widespread applications of Mg-based structural materials. Herein, an unexpected double-stage strengthening phenomenon was discovered in Mg-8Li-1Y(wt.%) alloys through high pressure (6 GPa) heat treatments over a range of 700-1300?°C. Attractively, the yield strength values are improved remarkably without losing their ductility. The low temperature strengthening mechanism is mainly driven by the formation of large-volume nanoscale contraction twins. In contrast, the high-temperature strengthening reason is ascribed to the presence of densely nano-sized stacking faults. Both coherent interfaces contribute effectively to high mechanical strength without any tradeoff in ductility.

Key words: Mg alloys, Nano-twins, Stacking faults, Strengthening

Shun Zhang, Yong Sun, Ruizhi Wu, Xiang Wang, Xiao-Bo Chen, Carlos Fernandez, Qiuming Peng. Coherent interface strengthening of ultrahigh pressure heat-treated Mg-Li-Y alloys[J]. J. Mater. Sci. Technol., 2020, 51: 79-83.

Figures/Tables 4

Fig. 1. Mechanical properties of UHPed LZY801 alloys as a function of processing temperature. (a) Effects of UHP conditions on microhardness. (b) Optical microstructure and XRD patterns. (c) Tensile and (d) compression curves. The insets correspond to macro-size optical photographs.

Fig. 2. Comparison in terms of mechanical properties between UHPed LZY801 alloys and a range of representative Mg-Li-X (alloying elements) alloys prepared by a variety of themal-mechanical treatments.

Fig. 3. TEM characterization of the LYZ801-6 GPa-900 alloy. (a) STEM micrographs of the as-cast LZY801 sample. (b) EDS mapping of Y in (a). (c) SAED pattern of α-Mg. (d) TEM image of the LZY801-6 GPa-900 observed along [11 112-0 0] axis. A randomly particle in the matrix is marked by a red arrow. (e) Atomic-level image of coherent contraction twin boundary. (f) High magnification image of the particle in (d). (g) Local atomic-level magnified region as marked in (f).

Fig. 4. Strengthening mechanisms in the LZY801-6 GPa-1200 alloy. (a) TEM image with an inset corresponding to the spacing distribution SFs derived from statistical calculations of 50 random results. (b) Corresponding SAED patterns, where crystal planes and SFs (streaking pattern) are marked. (c) Atomic level image of SFs in (a).

References 21

[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., 34(2018), pp. 245-247.
[2]	T.M. Pollock , Science, 328(2010), pp. 986-987.
[3]	W. Xu, N. Birbilis, G. Sha, Y. Wang, J.E. Daniels, Y. Xiao, M. Ferry , Nat. Mater., 14(2015), p. 1229.
[4]	X.Y. Li, Y.J. Wei, L. Lu, K. Lu, H.J. Gao , Nature, 464(2010), pp. 877-880.
[5]	P. Cizek, M.R. Barnett , Scr. Mater., 59(2008), pp. 959-962.
[6]	H. Fu, B.C. Ge, Y.C. Xin, R.Z. Wu, C. Fernandez, J.Y. Huang, Q.M. Peng , Nano. Lett., 17(2017), pp. 6117-6124.
[7]	Q.M. Peng, Y. Sun, B.C. Ge, H. Fu, Q. Zu, X.Z. Tang, J.Y. Huang , Acta. Mater., 169(2019), pp. 36-44.
[8]	J.F. Nie, Y.M. Zhu, J.Z. Liu, X.Y. Fang , Science, 340(2013), pp. 957-960.
[9]	B. Ahn, A.P. Zhilyaev, H.-J. Lee, M. Kawasaki, T.G. Langdon, Mat. Sci. Eng. A, 635(2015), pp. 109-117.
[10]	C.J. Shuai, W.J. Yang, Y.W. Yang, C.D. Gao, C.X. He, H. Pan , Int. J. Bioprint., 5(2019), p. 49.
[11]	G.Y. Sha, X.G. Sun, T. Liu, Y.H. Zhu, T. Yu, J. Mater. Sci. Technol., 27(2011), pp. 753-758.
[12]	D.K. Xu, T.T. Zu, M. Yin, Y.B. Xu, E.H. Han, J. Alloys. Compd., 582(2014), pp. 161-166.
[13]	T.L. Zhu, J.F. Sun, C.L. Cui, R.Z. Wu, S. Betsofen, Z. Leng, J.H. Zhang, M.L. Zhang , Mater. Sci. Eng. A, 600(2014), pp. 1-7.
[14]	M.L. Zhang, R.Z. Wu, T. Wang, J. Mater. Sci., 44(2009), pp. 1237-1240.
[15]	C.Q. Li, D.K. Xu, B.J. Wang, L.Y. Sheng, R.Z. Wu, E.H. Han, J. Mater. Sci. Technol., 35(2019), pp. 2477-2484.
[16]	Y. Tang, W.T. Jia, X. Liu, Q.C. Le, Y.L. Zhang , Mat. Sci. Eng. A, 675(2016), pp. 55-64.
[17]	Y. Yang, X.M. Xiong, J.F. Su, X.D. Peng, H.M. Wen, G.B. Wei, F.S. Pan, E.J. Lavernia, J. Alloys. Compd., 750(2018), pp. 696-705.
[18]	M. Karami, R. Mahmudi , Mat. Sci. Eng. A, 607(2014), pp. 512-520.
[19]	R.Z. Wu, Z.K. Qu, M.L. Zhang , Rev. Adv. Mater. Sci., 24(2010), pp. 35-43.
[20]	C.O. Muga, H. Guo, S.S. Xu, Z.W. Zhang , Mater. Sci. Eng. A, 689(2017), pp. 195-202.
[21]	M. Fornasini, J. Less-Common. Met., 25(1971), pp. 329-332.