Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (2): 266-280.DOI: 10.1007/s40195-022-01460-0

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Tailoring Texture to Highly Strengthen AZ31 Alloy Plate in the Thickness Direction via Pre-tension and Rolling-Annealing

Tianjiao Li1, Jiang Zheng1,2, Lihong Xia3(), Haoge Shou1, Yongfa Zhang1, Rong Shi1, Liuyong He1, Wenkai Li4   

  1. 1International Joint Laboratory for Light Alloys (Ministry of Education), College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, China
    2Shenyang National Laboratory for Materials Science, Chongqing University, Chongqing, 400044, China
    3College of Mechanical Engineering, Chongqing Technology and Business University, Chongqing, 400067, China
    4Zhejiang Provincial Engineering Center of Integrated Manufacturing Technology and Intelligent Equipment, Zhejiang University City College, Hangzhou, 310015, China
  • Received:2022-05-29 Revised:2022-07-26 Accepted:2022-07-27 Online:2023-02-10 Published:2022-09-30
  • Contact: Lihong Xia, lhxia@ctbu.edu.cn

Abstract:

Conventional wrought Mg alloys, such as AZ31 and ZK60 rolled plates, usually exhibit significantly low tensile yield strength in the thickness direction. This can be attributed to the high activity of {10-12} tension twinning due to the strong basal texture (< 0001 > //ND, normal direction). In this work, the tensile yield strength in the ND of the as-rolled (AR) AZ31 plate increased from 50 to 150 MPa (increased by 200%) via simple processing, i.e., pre-tension and rolling-annealing (PTRA) treatment. The strong basal texture (< 0001 > //ND) of the AR plate was changed into a weakened fiber texture (< 0001 > ⊥ND). The evolution of microstructures during PTRA treatment and the activated deformation modes during uniaxial tension were studied quantitatively and statistically by the means of intergranular misorientation (IM) and in-grain misorientation axes (IGMA) analysis. The results indicate that various twin variants, as well as {10-12}-{10-12} secondary twins, were activated during pre-tension and rolling, and most residual matrix was consumed by twins after annealing. The dominated deformation modes in tension changed from {10-12} tension twinning (the AR sample) to prismatic slip (the PTRA sample) in the early tensile deformation. The underlying formation mechanism of the fiber texture and corresponding strengthening mechanism were discussed.

Key words: Pre-tension, Annealing, Tailoring texture, Texture strengthening, Deformation modes