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采用真空压铸工艺制备GW63K合金,研究压射速度和真空度对组织及性能的影响。采用光学显微镜、SEM及EDX对组织进行观察。研究GW63K的热处理工艺。结果表明:铸态GW63K合金由α-Mg基体和Mg24(Gd,Y)5第二相组成,且随着压射速度的增加,合金的屈服强度没有大的变化,但是伸长率先增加后减小;真空辅助能够减少气孔的大小及含量。在475°C固溶2 h,然后在200°C下时效80 h,GW63K合金的抗拉强度和伸长率分别达到308 MPa和9.45%。首次发现预初晶(ESCs)的存在对压铸GW63K合金热处理性能有巨大影响,预初晶(ESCs)的存在严重降低热处理后合金的性能。
The vacuum die-casting process was used to prepare GW63K alloy, and the effects of injection speed and degree of vacuum on microstructure and properties were studied. The microstructure was observed by optical microscope, SEM and EDX. Research GW63K heat treatment process. The results show that the as-cast GW63K alloy consists of α-Mg matrix and Mg24 (Gd, Y) 5 second phase. With the increase of the injection velocity, the yield strength of the alloy does not change much, but the elongation increases first and then decreases Small; vacuum assisted to reduce the size and content of stomata. After heat treatment at 475 ° C for 2 h and then aging at 200 ° C for 80 h, the tensile strength and elongation of GW63K alloy reached 308 MPa and 9.45%, respectively. For the first time, it was found that the presence of pre-primary crystals (ESCs) had a great influence on the heat treatment properties of the die-cast GW63K alloy. Pre-primary crystallization (ESCs) seriously deteriorated the properties of the alloy after heat treatment.