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采用等通道转角挤压变形工艺,在573 K下以Bc路径对Mg-6Zn-2Si镁合金进行4道次和8道次挤压细化合金晶粒来提高其力学性能,同时对合金室温拉伸断口进行分析,并阐述了等通道挤压改善实验合金微观组织和力学性能的机理。结果表明:经4道次挤压后晶粒由310μm细化到13μm,Mg_2Si相最大约60μm,细化为细小颗粒状约7μm,α-Mg基体与Mg Zn相均得到显著细化,屈服强度提高180%,伸长率提高140%,抗拉强度提高75%。与4道次相比,经8道次挤压后微观组织无明显变化,屈服强度有所提高,抗拉强度和伸长率变化不大。合金的室温拉伸断口由铸态合金的脆性断口过渡为韧性断口,并且韧窝加深,分布更均匀。
The isotropic channel deformation process was used to improve the mechanical properties of Mg-6Zn-2Si magnesium alloy by Bc path at 573 K for 4 and 8 passes to improve its mechanical properties. Meanwhile, Elongation fracture analysis, and describes the mechanism of equal channel extrusion to improve the microstructure and mechanical properties of the experimental alloy. The results show that the grains are refined from 310μm to 13μm after extruding for 4 passes, the maximum of Mg_2Si phase is about 60μm, the size of fine particles is about 7μm, and both the α-Mg matrix and Mg Zn phase are remarkably refined. The yield strength Increased by 180%, elongation increased by 140%, tensile strength increased by 75%. Compared with 4 passes, after 8 passes of extrusion, the microstructure did not change obviously, the yield strength increased, and the tensile strength and elongation changed little. Tensile fracture of the alloy at room temperature transition from brittle fracture of the as-cast alloy to ductile fracture, and dimples deepen, more evenly distributed.