Mg-Gd-Y-Sm-Zr alloy with fine grains and weak texture was fabricated by extrusion-shear (ES) process. The microstructure evolution mechanism of the alloy during asymmetric plastic deformation process was analyzed. At the forward extrusion stage, the initial coarse grains are refined significantly under the synergistic action of discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and deformation bands (DBs) induced dynamic recrystallization (DRX). The shear deformation during equal channel angular pressing (ECAP) can further refine the residual coarse grains after the previous extrusion, as well as weaken the basal texture of the alloy. The effect of extrusion ratio(λ = 9, 16, 25, 36) on the alloy after ES forming was studied. When λ is 25, the component has superior mechanical properties with yield tensile strength (YTS) of 216 MPa, ultimate tensile strength (UTS) of 303 MPa and elongation of 25.47%. The improvement of YTS after ES forming is mainly attributed to the grain boundary strengthening, while the excellent elongation is benefited from the weak bimodal texture. Abnormal grain growth will occur when λ is 36, leading to a decrease in the strength and plasticity of the alloy.

中文翻译：

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非对称挤压剪切工艺细化Mg-Gd-Y-Sm-Zr合金晶粒细化和织构弱化的合作成果

采用挤压剪切（ES）工艺制备了细晶粒、弱织构的Mg-Gd-Y-Sm-Zr合金。分析了合金在不对称塑性变形过程中的微观组织演化机制。在正向挤压阶段，在不连续动态再结晶（DDRX）、连续动态再结晶（CDRX）和变形带（DBs）诱发动态再结晶（DRX）的协同作用下，初始粗大晶粒显着细化。等通道角挤压（ECAP）过程中的剪切变形可以进一步细化前次挤压后残留的粗晶，并削弱合金的基础织构。研究了挤压比(λ=9、16、25、36)对ES成形后合金的影响。当λ为25时，该部件具有优异的力学性能，屈服拉伸强度（YTS）为216 MPa，极限拉伸强度（UTS）为303 MPa，伸长率为25.47%。ES成形后YTS的改善主要归因于晶界强化，而优异的延伸率则得益于弱的双峰织构。当λ为36时，会出现晶粒异常长大，导致合金的强度和塑性下降。