High-speed extrusion of dilute Mg-Zn-Ca-Mn alloys and its effect on microstructure, texture and mechanical properties

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:678

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;    Microstructure;    Texture;    Mechanical properties;   

DOI  :  10.1016/j.msea.2016.10.007

来源: Elsevier

【 摘 要 】

Three dilute Mg-Zn-Ca-Mn alloys were successfully extruded at 24 m/min and the alloy with lowest Zn content (0.21 wt%) can even be extruded at 60 m/min without any surface defects, which was ascribed to the thermally stable Mg2Ca phase and high solidus temperature (similar to 620 degrees C). The alloys extruded at die-exit speed >= 6 m/min showed a fully dynamically recrystallized (DRXed) microstructure and weak rare earth (RE) texture at the position between [2114] and [2112] parallel to the extrusion direction. Besides, fine Mg2Ca and alpha-Mn particles dynamically precipitated during extrusion, acting as effective pinning obstacles against the DRXed grain growth via Zener drag effect. Due to the deformation temperature rise with increasing extrusion speeds, the grain size increased gradually, which can be understood from the relationship between DRXed grain size and Zener-Hollomon parameter. The RE texture contributed to high uniform elongation of similar to 23%, but the increased grain size ( > 30 mu m) deteriorated post-uniform elongation due to the prevalence of {10 (1) over bar1} contraction and {10 (1) over bar1}-{10 (1) over bar2} double twins during post-uniform deformation.

【 授权许可】

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