热等静压对低压铸造WE43镁合金组织和室温及高温力学性能的影响

Effect of hot isostatic pressing on microstructure,room temperature and high temperature mechanical properties of low-pressure casting WE43 magnesium alloy

采用低压金属型铸造方法制备了WE43(Mg-4.1Y-2.3Nd-1.5Gd-0.5Zr)镁合金,对其进行了热等静压处理。利用光学显微镜、扫描电镜、能谱仪和拉伸试验等分析了合金的显微组织和室温及高温下的力学性能,研究了热等静压对低压铸造WE43镁合金组织和力学性能的影响。结果表明:低压铸造得到的WE43合金晶粒细小,时效态合金的屈服强度为(197.7±1.2)MPa、抗拉强度为(287.0±12.0)MPa、断后伸长率为(6.7±3.1)%。热等静压显著提高了合金的抗拉强度与塑性,经过热等静压之后,时效态合金的屈服强度为(199.0±2.0)MPa、抗拉强度为(306.7±7.8)MPa、断后伸长率为(8.0±1.7)%。由低压铸造-热等静压工艺制备的WE43合金在室温至250℃范围内表现出优异的力学性能,其原因是合金具有细小的晶粒组织以及消除了缩松缩孔。

WE43(Mg-4.1Y-2.3Nd-1.5Gd-0.5Zr)magnesium alloy was prepared by low-pressure metal mold casting,and was treated by hot isostatic pressing.Microstructure and room temperature and high temperature mechanical properties of the alloy were analyzed by means of optical microscope,scanning electron microscopy,energy dispersive spectrometer analysis and tensile testing.The effect of hot isostatic pressing on the microstructure and mechanical properties of the low-pressure casting WE43 magnesium alloy was studied.The results show that the WE43 alloy obtained by low-pressure casting has fine grains,and the yield strength,tensile strength and elongation of the aged alloy are(197.7±1.2)MPa,(287.0±12.0)MPa and(6.7±3.1)%,respectively.The hot isostatic pressing can significantly improve the tensile strength and plasticity of the alloy.After hot isostatic pressing,the yield strength of the aged alloy is(199.0±2.0)MPa,the tensile strength is(306.7±7.8)MPa,and the elongation is(8.0±1.7)%.The WE43 alloy prepared by low-pressure casting+hot isostatic pressing process shows excellent mechanical properties in the range of room temperature to 250℃,which is due to the fine grain structure of the alloy and the elimination of shrinkage porosity and pores.