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基于各种零部件对非稀土型低成本镁合金的需求,选择低成本Bi添加镁合金作为研究对象,对比研究了纯Mg及其添加6%Bi(质量分数)的Mg-6Bi合金的微观组织与力学性能.结果表明,2种样品在挤压后均发生了完全动态再结晶且表现出相似的挤压织构,但Bi加入后可获得更为均匀细小的组织,平均晶粒尺寸从未添加态的30μm显著减小为4μm.Mg-6Bi合金中未完全固溶的微米级Mg3Bi2相在挤压过程中被破碎并沿挤压方向呈条带状分布,同时观察到大量动态析出的纳米级Mg3Bi2相弥散分布在基体中.挤压态Mg-6Bi合金的力学性能较纯Mg显著提高,其拉伸屈服强度、抗拉强度和延伸率分别达到189 MPa,228 MPa和19.9%,且未表现出拉压各向异性.添加Bi后合金性能的提高主要归因于晶粒细化和弥散分布的微纳双尺寸Mg3Bi2相协同强化的共同作用.
Based on the demand of non-rare-earth low-cost magnesium alloy for various components, low-cost Bi-doped magnesium alloy was selected as the research object. The microstructure of pure Mg and its Mg-6Bi alloy with 6% Bi And mechanical properties.The results show that the two samples all undergo complete dynamic recrystallization and exhibit similar extrusion texture after extrusion, but more uniform and fine texture can be obtained after adding Bi, the average grain size has never been The microstructure of Mg-6Bi alloy, Mg3Bi2, which has not been completely dissolved, was broken during the extrusion and distributed in the form of stripes along the extrusion direction. A large number of nano-particles Grade Mg3Bi2 phase dispersed in the matrix.The mechanical properties of the as-extruded Mg-6Bi alloy were significantly improved compared with the pure Mg, and the tensile yield strength, tensile strength and elongation reached 189 MPa, 228 MPa and 19.9% respectively Showing the tensile and compressive anisotropy.Improvement of the properties of the alloy after addition of Bi is mainly attributed to the synergetic effect of the grain refinement and the diffusion-enhanced micro-nano dual-size Mg3Bi2 synergistic strengthening.