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研究不同状态WE93合金的组织与室温力学性能,以及时效态合金在温度200°C,应力100、125和150MPa条件下的蠕变性能。结果表明:WE93合金铸态组织由α-Mg、Mg12(MM)及Mg24Y5相组成,其平均晶粒尺寸为45μm。铸态合金经535°C保温18h均匀化处理后,Mg24Y5相基本完全分解,晶界周围仅残留MM相,晶粒尺寸随着保温时间的延长未见明显长大。挤压态合金较铸态合金具有更好的力学性能,尤其是其延伸率达到12.5%。经过时效处理的挤压态合金的屈服强度及断裂强度最高,分别为315和385MPa,但延伸率降至6.5%。经时效处理后的挤压态合金在200°C,应力100150MPa条件下具有较好的抗蠕变性能,应力指数为2.97,说明在相应的温度及应力条件下晶界滑移为该合金的主要蠕变机制。
The microstructure and room temperature mechanical properties of WE93 alloy were studied, and the creep properties of aged alloys at 200 ℃ and 100, 125 and 150MPa were investigated. The results show that the as-cast microstructure of WE93 alloy consists of α-Mg, Mg12 (MM) and Mg24Y5 phases with the average grain size of 45μm. After the as-cast alloy was homogenized at 535 ° C for 18h, the Mg24Y5 phase was completely decomposed, leaving only the MM phase around the grain boundaries. The grain size did not increase obviously with the prolongation of the holding time. Extruded alloys have better mechanical properties than as-cast alloys, especially with an elongation of 12.5%. After aging treatment of the extruded alloy highest yield strength and fracture strength, respectively 315 and 385MPa, but the elongation dropped to 6.5%. After aging treatment, the extruded alloy has better creep resistance under stress of 100150MPa and stress index of 2.97 at 200 ° C, indicating that the grain boundary slip is the main component of the alloy under the corresponding temperature and stress conditions Creep mechanism.