J. Mater. Sci. Technol. ›› 2020, Vol. 41: 98-104.DOI: 10.1016/j.jmst.2019.05.076

Special Issue: 镁合金2020-2021

• Research Article • Previous Articles     Next Articles

On the texture memory effect of a cross-rolled Mg-2Zn-2Gd plate after unidirectional rolling

Pengfei Zhanga, Yunchang Xinab*(), Ling Zhanga*(), Shiwei Panc, Qing Liuab   

  1. aInternational Joint Laboratory for Light Alloys, College of Materials Science and Engineering, Chongqing University, Chongqing, 400030, China
    bNational Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing, 400044, China
    cState Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China
  • Received:2019-02-24 Revised:2019-05-12 Accepted:2019-05-13 Published:2020-03-15 Online:2020-04-10
  • Contact: Xin Yunchang,Zhang Ling

Abstract:

A Mg-2Zn-2Gd alloy subjected to a cross rolling and annealing often has a texture with c-axes of grains evenly distributing on a circle approximately 40° away from the normal direction (ND), which can completely remove the planar mechanical anisotropy. The texture memory effect and planar mechanical anisotropy of such a cross-rolled plate after an unidirectional rolling and subsequent annealing were systematically investigated. The results show that the circle-shaped texture is partially retained after the unidirectional rolling and annealing, with basal poles evenly distributing on an ellipse approximately 30°-40° away from the ND. This small texture difference will lead to quite different mechanical anisotropies between the two plates, namely, a quite low anisotropy of yield strength between the rolling direction (RD) and transverse direction (TD) before the unidirectional rolling, in contrast to an obvious mechanical anisotropy after unidirectional rolling. A quantitative calculation shows that tension along the RD of the plate after the unidirectional rolling will activate a much higher fraction of prismatic slip than tension along the TD. The much higher critical resolved shear stress for prismatic slip than that for basal slip or {10 $\bar{1}$ 2} twinning accounts for the much higher yield strength of TD tension than that of RD tension. The mechanisms for texture evolution during the unidirectional rolling and annealing were also discussed.

Key words: Magnesium alloys, Rolling, Texture, Mechanical anisotropy