In this work, two wrought Mg-3.66Al-4.25Ca-0.43 Mn (wt%) alloys with different morphology and distribution of Mg₂Ca particles were fabricated by hot extrusion and multi-pass (32) equal channel angular pressing (ECAP). The as-extruded alloy exhibits a banded microstructure with alternately arranged Mg₂Ca particle bands, fine α-Mg dynamically recrystallized (DRX) grain bands, and coarse α-Mg deformed grain bands. The Mg₂Ca bands are composed of broken Mg₂Ca particles which are aggregated and aligned along extrusion direction. The microstructure of ECAP alloy contains complete α-Mg DRX grains and refined Mg₂Ca particles which are dispersedly distributed at grain boundaries. Tensile test results show that the as-extruded alloy possesses high ultimate tensile strength (UTS) of 420 MPa and poor fracture elongation of 7 %, while the ECAP alloy exhibits improved toughness with UTS of 347 MPa and fraction elongation of 16 %. The higher strength of as-extruded alloy is mainly ascribed to the contribution of coarse deformed grains with strong texture, and its poor toughness is resulted from the formation of Mg₂Ca bands within which microcracks could form and extend rapidly. On the contrary, the refined and dispersedly distributed Mg₂Ca particles are effective to retard crack initiation and impede crack propagation, thereby enhancing the toughness of ECAP alloy significantly.

在这项工作中，通过热挤压和多道次（32）等通道角压制（ECAP）制备了两种形态不同的Mg ₂ Ca颗粒的Mg-3.66Al-4.25Ca-0.43 Mn（wt％）变形合金。 。挤压后的合金表现出带状的微观结构，具有交替排列的Mg ₂ Ca颗粒带，细小的α-Mg动态重结晶（DRX）晶粒带和粗大的α-Mg变形晶粒带。Mg ₂ Ca带由破碎的Mg ₂ Ca颗粒组成，这些颗粒聚集并沿着挤出方向排列。ECAP合金的微观结构包含完整的α-MgDRX晶粒和精制的Mg ₂Ca颗粒分散在晶界处。拉伸试验结果表明，挤压后的合金具有420 MPa的高极限抗拉强度（UTS）和7％的较差的断裂伸长率，而ECAP合金具有347 MPa的UTS和16％的延伸率的改进韧性。挤压后合金的较高强度主要归因于具有强织构的粗大变形晶粒的贡献，而其韧性差是由于形成了Mg ₂ Ca带，在该带中微裂纹可能迅速形成和扩展。相反，细化且分散分布的Mg ₂ Ca颗粒可有效地阻止裂纹萌生并阻止裂纹扩展，从而显着提高ECAP合金的韧性。