J. Mater. Sci. Technol. ›› 2020, Vol. 43: 104-118.DOI: 10.1016/j.jmst.2020.01.018

• Research Article • Previous Articles     Next Articles

Unveiling annealing texture formation and static recrystallization kinetics of hot-rolled Mg-Al-Zn-Mn-Ca alloy

Qinghang Wanga, Bin Jiangab*(), Aitao Tanga, Jie Fua, Zhongtao Jiangc, Haoran Shengd, Dingfei Zhanga, Guangsheng Huangab, Fusheng Panab   

  1. a State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
    b Chongqing Academy of Science and Technology, Chongqing 401123, China
    c Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China
    d Shanghai Aerospace Equipment Manufactory, Shanghai 200245, China
  • Received:2019-07-17 Revised:2019-09-04 Accepted:2019-09-24 Published:2020-04-15 Online:2020-04-26
  • Contact: Jiang Bin

Abstract:

The development of Mg-Al-Zn-Mn-Ca series alloys provides a potential prospect to achieve high strength and formability at room temperature (RT). The formation of elliptical annular texture is treated as a crucial factor for the enhanced RT formability. However, the origin of such an elliptical annular texture formation has been rarely reported. Herein, we unveiled the formation and evolution of elliptical annular texture in the hot-rolled Mg-1.6Al-0.8Zn-0.4Mn-0.5Ca (AZMX1100, wt.%) alloy after annealing at different temperatures for 1 h, and its static recrystallization (SRX) kinetics in given annealing temperature for different time. The results revealed that the formation of elliptical annular texture in the hot-rolled AZMX1100 alloy after annealing was derived from nucleation-oriented SRX mechanism, which took place in 200-300 °C, induced by cracked chain-shaped Al2Ca phases, contraction twins, intersections of double twins, intersections of double twins and grain boundaries and non-basal slips. On further annealing from 300-450 °C, the grains with 45°-70° transverse direction (TD) preferentially grew, which made elliptical annular texture extended along the TD. Based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, Avrami exponent n value was estimated to be 0.68-1.02, attributed to non-random SRX nucleation, giving rise to the lower activation energy QR of nucleation of ~74.24 kJ/mol. Since the co-segregation of Al, Zn and Ca atoms in grain boundaries created a strong interaction of solutes and grain boundaries, the hot-rolled AZMX1100 alloy exhibited the higher activation energy Qg (~115.48 kJ/mol) of grain growth.

Key words: Mg-Al-Zn-Mn-Ca alloy, Elliptical annular texture, Nucleation, Grain growth, Static recrystallization kinetics