Enhancing strength and ductility of Mg-Zn-Gd alloy via slow-speed extrusion combined with pre-forging

JOURNAL OF ALLOYS AND COMPOUNDS

卷:694

Article

Jiang, M. G.^1,2  Xu, C.³  Nakata, T.³  Yan, H.¹  Chen, R. S.¹  Kamado, S.³ 

[1] Chinese Acad Sci, Inst Met Res, Grp Magnesium Alloys & Their Applicat, 62 Wencui Rd, Shenyang 110016, Peoples R China

[2] Univ Chinese Acad Sci, 19 Yuquan Rd, Beijing 100049, Peoples R China

[3] Nagaoka Univ Technol, Dept Mech Engn, Nagaoka, Niigata 9402188, Japan

关键词: Magnesium alloy;    Extrusion;    Forging;    Microstructure;    Mechanical properties;   

DOI  :  10.1016/j.jallcom.2016.10.109

来源: Elsevier

【 摘 要 】

Mg-1.58Zn-0.52Gd (wt.%) alloy was subjected to slow-speed extrusion at 350 degrees C and 400 degrees C combined with hot pre-forging. The extruded alloy without pre-forging exhibited a bimodal microstructure, consisting of fine dynamically recrystallized (DRXed) grains and coarse unDRXed grains elongated along the extrusion direction, and strong basal texture, while pre-forging changed the bimodal structure into fully DRXed microstructure with finer grains and weaker extrusion texture. The fine and homogeneous extruded microstructure in the pre-forged alloy was mainly ascribed to the combined effect of refined starting microstructure just before extrusion, continuous DRX mechanism during extrusion and pinning effect induced by fine Mg3Zn3Gd2 precipitates. The pre-forged alloy exhibited superior balance of strength and ductility, as well as yield asymmetry, to the non-forged alloy after extrusion. The pre-forged alloy extruded at 350 degrees C and 400 degrees C showed highly improved elongation of 27.9% and 34.8%, respectively, mainly due to the formation of fully DRXed microstructure with fine grains through suppressing the activity of {10 (1) over bar 1} contraction and {10 (1) over bar 1}-{10 (1) over bar 2} double twins during tensile deformation. (C) 2016 Elsevier B.V. All rights reserved.

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