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采用常规铸造方法制备AZ31-4.6%Mg2Si复合材料,在400°C对铸态复合材料进行1、3和5道次的反复镦压(RU)剧烈变形。材料流动的有限元分析表明:1道次后变形集中于试样底部区域,5道次后可获得均匀的变形。多道次反复镦压过程中基体施加的剪切应力使树枝状和汉字状Mg2Si相破碎成小颗粒,随着反复镦压道次的增加,晶粒尺寸逐渐减小,Mg2Si颗粒分布逐渐均匀,同时强度和塑性显著提高,在400°C反复镦压5道次后,AZ31-4.6%Mg2Si复合材料抗拉强度和伸长率分别为248 MPa和9.8%,而原始铸态复合材料的抗拉强度和伸长率分别只有128 MPa和5.4%。
AZ31-4.6% Mg2Si composites were prepared by conventional casting method and subjected to repeated rupture (RU) deformation at 1, 3 and 5 times of the as-cast composites at 400 ° C. Finite element analysis of material flow shows that after 1 pass, the deformation is concentrated in the bottom area of the sample, and uniform deformation can be obtained after 5 passes. The shear stress applied by the substrate during the repeated multiple upsetting process breaks the dendritic and kink-shaped Mg2Si phases into small particles, and as the number of repeated upsetting passes increases, the grain size decreases and the distribution of the Mg2Si particles gradually becomes uniform. At the same time, the strength and ductility increased significantly. The tensile strength and elongation of AZ31-4.6% Mg2Si composites were 248 MPa and 9.8% respectively after repeated upsetting at 400 ° C for 5 passes. The tensile strength of the original as-cast composites And elongation of only 128 MPa and 5.4% respectively.