Mechanical Behavior of AZ31B Mg Alloy Sheets under Monotonic and Cyclic Loadings at Room and Moderately Elevated Temperatures

Materials

Ngoc-Trung Nguyen¹  Oh Suk Seo²  Chung An Lee²  Myoung-Gyu Lee¹  Ji-hoon Kim³ 

[1] Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, San 31 Hyoja-dong, Nam-gu, Pohang, Gyeongbuk 790-784, Korea; E-Mail:;Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja2-dong, Chuncheon, Gangwon-do 200-701, Korea; E-Mails:;School of Mechanical Engineering, Pusan National University Jangjeon-dong, Geumjeong-gu, Busan 609-735, Korea; E-Mail:

关键词: yielding asymmetry;    anisotropy;    hardening;    tension/compression loading;    Young’s modulus;   

DOI  :  10.3390/ma7021271

来源: mdpi

【 摘 要 】

Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C. Behaviors showing significant twinning during initial in-plane compression and untwinning in subsequent tension at and slightly above room temperature were recorded. Strong yielding asymmetry and nonlinear hardening behavior were also revealed. Considerable Bauschinger effects, transient behavior, and variable permanent softening responses were observed near room temperature, but these were reduced and almost disappeared as the temperature increased. Different stress–strain responses were inherent to the activation of twinning at lower temperatures and non-basal slip systems at elevated temperatures. A critical temperature was identified to account for the transition between the twinning-dominant and slip-dominant deformation mechanisms. Accordingly, below the transition point, stress–strain curves of cyclic loading tests exhibited concave-up shapes for compression or compression following tension, and an unusual S-shape for tension following compression. This unusual shape disappeared when the temperature was above the transition point. Shrinkage of the elastic range and variation in Young’s modulus due to plastic strain deformation during stress reversals were also observed. The texture-induced anisotropy of both the elastic and plastic behaviors was characterized experimentally.

【 授权许可】

CC BY   
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