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通过铸造和300℃热加压制备细晶Mg-6Zn-4Y合金,利用XRD、OM、SEM和TEM研究合金组织,并测试其室温拉伸性能。结果表明,合金主要由α-Mg和W相两相组成,挤压态合金具有双峰晶粒尺寸分布;细小晶粒为动态再结晶晶粒,平均尺寸为1.2μm;粗大晶粒(占面积分数的23%)为未再结晶区域,并沿挤压方向被拉长。合金的极限抗拉强度、屈服强度和伸长率分别为(371±10)MPa,(350±5)MPa和(7±2)%,其工程应力—应变曲线有明显的屈服点。合金高强度归因于晶粒细化和W相、纳米沉淀颗粒及强基面织构的增强作用。
The fine grained Mg-6Zn-4Y alloy was prepared by casting and hot pressing at 300 ℃. The alloy structure was investigated by XRD, OM, SEM and TEM, and the tensile properties at room temperature were tested. The results show that the alloy consists of two phases, α-Mg and W phases, and the as-extruded alloy has a bimodal grain size distribution. The fine grains are dynamically recrystallized grains with an average size of 1.2 μm. The coarse grains 23% of the fraction) is the non-recrystallized region and is elongated in the extrusion direction. The ultimate tensile strength, yield strength and elongation of the alloy are (371 ± 10) MPa, (350 ± 5) MPa and (7 ± 2)%, respectively, and the stress-strain curve has obvious yield point. The high strength of the alloy is attributed to grain refinement and W-phase, nano-precipitated particles and strong basal texture enhancement.