AZ91D镁合金触变铸造件热处理前后组织与性能研究

Research on the Microstructure and Mechanical Properties of AZ91D Magnesium Alloy Part in Thixo-casting Processing Pre/pro Heat Treatment

采用低过热铸造技术与半固态触变成形技术相结合,直接在高压铸造机中成功制备了摩托车发动机支架镁合金件。试验结果表明:半固态成形件试样与热处理试样中的未熔α-Mg相细小、圆整而且分布均匀,微观组织没有气孔和缩松;与没有热处理的半固态压铸成形件相比,固溶态试样的硬度和抗拉强度分别降低了4.5%和3.1%,而固溶时效态试样的硬度和抗拉强度分别提高了30.1%和14.0%,两种热处理工艺均使得材料的伸长率分别比没有热处理的试样提高17.6%和40.5%。

The low super heat processing and semi-solid thixo-casting processing are adapted to fabricate the AZ91D magnesium alloy generator's brackets in JH70 motorcycle in die casting machine successfully.The experimental results shows that the unmelted α-Mg phase in the semi-solid casting and semi-solid casting with heat treatment samples,which has no void and shrinkage,is thin,and scatteredon the α-Mg17Al12 eutecticphase uniformly.Comparing with the semi-solid sample with heat treatment,the hardness and tensile strength of the sample with T4 heat treatment degrade about 4.5% and 3.1% respectively,and those with T4 heat treatment increase about 30.1% and 14% respectively,furthermore,the elongation of the sample with T4 and T6 heat treatment increases 17.6% and 40.5% respectively.