深冷处理对铸态ZK60镁合金显微组织和力学性能的影响

Effect of Deep Cryogenic Treatment on Microstructure and Mechanical Properties of As-Cast ZK60 Magnesium Alloy

选用工业化生产的半连铸ZK60镁合金为研究对象,采用力学性能检测设备、光学显微镜、X射线衍射仪和透射电镜等研究了深冷处理(77 K)对其显微组织和力学性能的影响。结果表明:深冷处理可以细化ZK60合金的显微组织,引起一定程度的晶粒转动并促进微细第二相析出,产生了细晶强化及第二相析出强化,使ZK60合金的屈服强度由150.5 MPa提高到175.8 MPa,显微硬度由65.91 HV提高到74.03 HV,伸长率由17.5%提高到21.0%。

By taking a commercial production semi-continuous casting ZK60 magnesium alloy as the research objection,the effect of deep cryogenic treatment（DCT） at 77 K on the microstructure and mechanical properties was analyzed by means of mechanical property testing equipment,optical microsopy,X-ray diffraction and transmission electron microscopy.The results show that DCT could refine the microstructure,cause some grain orientation and improve the fine second phase precipitates,that resulted in fine grain strengthening and second phase precipitate strengthening.After cryogenic treatment yield strength of the ZK60 magnesium alloy reached from 150.5 MPa to 175.8 MPa,the microhardness increased from 65.91 HV to 74.03 HV and the elongation increased from 17.5% to 21.0%.