Microstructure and texture evolution of the β-Mg17A12 phase in a Mg alloy with an ultra-high Al content

• 作者: Changjian Yan Yunchang Xin Ce Wang Huan Liu Qing Liu
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（17）
• 页码范围: 89-99
• 页数: 11页
• 语种: 英文

摘要

In the present study,the effects of equal channel angular pressing (ECAP) on the microstructure and mechanical property of the Mg-20Al alloy were systematically investigated.For the first time,the tex-ture of Mg17Al12 phase and its evolution with ECAP conditions were reported.The results show that increasing the processing temperature and passes generates more uniform distribution and finer size of β-Mg17Al12 phases.The large pieces of β-Mg17Al12 phases are composed of many fine grains with differ-ent crystallographic orientations.For the β-Mg17Al12 phase,a preferred distribution of (001) appears at 523 K and 573 K,and hardly varies with temperature.Nevertheless,a random texture is observed at 623 K.The (0002) poles exhibit a preferred distribution at 473 K,but this preferred distribution varies with temperature.A random distribution of (0002) poles is observed when processed at 623 K.Many types of crystallographic planar relationship between β-Mg17Al12 phase and α-Mg matrix are observed and the relationships of {11-23}//{100} or {110} or {111} and {1-211}//{100} or//{110} or {111} have a relatively higher frequency than others.The texture of α-Mg matrix is much different from that of the ECAPed Mg alloys with a relative low Al content,in which a texture with basal poles inclining approx-imately 45° away from the extrusion direction often develops.The mechanical properties of Mg-20Al alloy are closely related to the temperature and passes of ECAP.A higher temperature often decreases the yield strength,but hardly alters the maximum strength.There is a low plasticity for all the samples and increasing processing temperature slightly enhances the plasticity.The corresponding mechanisms were deeply discussed.