Hardening mechanism of commercially pure Mg processed by high pressure torsion at room temperature

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

卷:619

Article

Qiao, Xiao Guang¹  Zhao, Ya Wei¹  Gan, Wei Min²  Chen, Ying³  Zheng, Ming Yi¹  Wu, Kun¹  Gao, Nong³  Starink, Marco J.³ 

[1] Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Peoples R China

[2] Helmholtz Zentrum Geesthacht, Inst Mat Res, D-21502 Geesthacht, Germany

[3] Univ Southampton, Mat Res Grp, Southampton SO17 1BJ, Hants, England

关键词: High pressure torsion;    Magnesium;    Non-basal slip;    Tension twinning;    Texture strengthening;    Hardness anisotropy;   

DOI  :  10.1016/j.msea.2014.09.068

来源: Elsevier

【 摘 要 】

Coarse-grained Mg in the as-cast condition and fine-grained Mg in the extruded condition were processed by high pressure torsion (HPT) at room temperature for up to 16 turns. Microstructure observation and texture analysis indicate that to fulfil the Von Mises criterion, the non-basal slip is activated in the as-cast Mg and tension twinning is activated in the as-extruded Mg. Although the deformation mechanism is different in the as-cast Mg and the as-extruded Mg during HPT, their hardening evolutions are similar, i.e. after 1/8 turn of HPT, microhardness of the as-cast Mg and the extruded Mg both show a significant increase and further HPT processing does not significantly further increase the microhardness. Texture strengthening can explain the rapid hardening. Hardness anisotropy and texture data results suggest that texture strengthening plays an important role for both types of samples. Texture strengthening weakens with decreasing grain size. (C) 2014 Elsevier B.V. All rights reserved.

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