挤压铸造工艺对含Y2wt% AZ91D稀土镁合金组织与性能的影响

Effect of Squeeze Casting Process on Microstructure and Properties of AZ91D Alloy with 2wt% Rare Earth Y

研究了挤压铸造工艺参数(挤压压力、浇注温度和保压时间)对含2wt%Y的AZ91D稀土合金组织与性能的影响。采用X射线衍射、金相分析、拉伸试验和SEM等方法分析了合金挤压态和固溶时效态的显微组织及其力学性能。结果表明:浇注温度对镁合金组织和性能影响最大,挤压压力其次,最后是保压时间。试验获得最佳工艺参数为:浇注温度720℃、挤压压力100 MPa、保压时间25 s。试样最大抗拉强度达到241.56 MPa、伸长率12.4%、布氏硬度80.06HB。固溶时效后铸件的力学性能明显提高,组织晶粒更细小且分布均匀。

The effects of squeeze casting parameters （squeeze casting pressure, pouring temperature and holding time） on the mechanical properties of AZ91D alloy with 2 wt% rare earth Y incorporated were investigated. The microstructure and mechanical properties of as-extruded and solid-solution treated AZ91 were analyzed using X-ray diffraction, tensile test, microscope, SEM and energy spectrum ect. The results indicate that the main affecting factor is pouring temperature, the next is squeeze casting pressure and the last is holding time. The best process parameters are as follows. The pouring temperature is 720℃, squeeze casting pressure is 100 MPa, holding time is 25 s. The ultimate tensile strength, elongation and brinell hardness of the samples is 241.56MPa, 12.4% and 80.06HB, respectively. The refmed grains distribute uniformly and the mechanical properties improve significantly after solution and aging.