Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (9): 1551-1563.DOI: 10.1007/s40195-024-01744-7

Previous Articles     Next Articles

Detwinning and Anneal-Hardening Behaviors of Pre-Twinned AZ31 Alloys under Cryogenic Loading

Lingyu Zhao1,4, Wei Zhu1, Chao Zhang1, Yunchang Xin2(), Changjian Yan3(), Yao Cheng2, Zhaoyang Jin1()   

  1. 1School of Mechanical Engineering, Yangzhou University, Yangzhou, 225127, China
    2Key Laboratory for Light-Weight Materials, Nanjing Tech University, Nanjing, 210009, China
    3Institute of Corrosion Science and Technology, Guangzhou, 510070, Guangdong, China
    4Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing Institute of Technology, Nanjing, 211167, China

Abstract:

Detwinning behavior of a pre-twinned magnesium alloy AZ31 at cryogenic temperature was investigated, also with a focus on the annealing hardening behavior of samples with different fractions of pre-twins. Pre-compression along the transverse direction with strains of 1.7%, 3.0%, and 6.0% was applied to generated $\left\{ {10\overline{1}2} \right\}$ twins. Mechanical behavior, microstructure, and texture evolution during subsequent tension were examined. Our results show that low temperature did not change the fact that detwinning still pre-dominated in the pre-twinned samples under reverse loading. However, a relatively harder migration of twin boundaries was found at cryogenic temperature. An annealing hardening of 27-40 MPa was observed in the pre-twinned samples, and such a hardening effect shows a close relation with the fraction of pre-twins or the level of pre-strains. The annealing hardening effect disappeared if the matrix was consumed by twins along with the increased pre-compression strains. The corresponding reasons for the annealing hardening behavior were discussed.

Key words: Mg alloys, Detwinning, Annealing hardening, Cryogenic temperature, Mechanical property