Micromechanical origin of the enhanced ductility in twinless duplex Mg-Li alloy

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

卷:815

Article

Xie, Di¹  Lyu, Zongyang¹  Fan, Mingyu²  Chew, Huck Beng³  Liaw, Peter K.¹  Bei, Hongbin⁴  Zhang, Zhongwu²  Gao, Yanfei¹ 

[1] Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA

[2] Harbin Engn Univ, Coll Mat Sci & Chem Engn, Key Lab Superlight Mat & Surface Technol, Minist Educ, Harbin 150001, Peoples R China

[3] Univ Illinois, Dept Aerosp Engn, Urbana, IL 61801 USA

[4] Zhejiang Univ, Sch Mat Sci & Engn, Hangzhou 310058, Peoples R China

关键词: Magnesium-lithium alloy;    Duplex microstructure;    Ductility;    In situ neutron diffraction;   

DOI  :  10.1016/j.msea.2021.141305

来源: Elsevier

【 摘 要 】

Unlike many Mg alloys that exhibit limited ductility, duplex Mg-Li alloys possess enhanced ductility but the underlying mechanisms are unclear. Using real-time in situ neutron diffraction measurements, we show that the underlying deformation modes in this duplex microstructure include an early yield of body-centered-cubic (BCC) beta-Li phase and the later elevated hardening in this phase at large macroscopic plastic strain, and the sequential activation of basal and pyramidal a slip systems in hexagonal-close-packed (HCP) alpha-Mg phase. The latter relieves the Mises constraint for deformation compatibility, and the successive yielding sequence promotes the overall work hardening rate, both of which are beneficial for ductility enhancement. No obvious twinning activities were found and correspondingly the hysteresis loops were symmetric upon a full loading cycle within +/- 1% applied strain.

【 授权许可】

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