(1. 北京科技大学 材料科学与工程学院，北京 100083；
2. 东莞宜安科技有限公司，东莞 523662)
摘 要: 利用Procast模拟软件分析AZ91D镁合金薄壁手机支架件的充型过程与凝固过程；结合模拟与实验研究不同工艺参数对薄壁压铸件表面质量、密度、组织及力学性能的影响，并探索出合适的工艺参数。结果表明：薄壁支架件所产生的缺陷类型及位置与模拟结果相吻合；浇注温度和快压射速度对薄壁件的压铸成形具有重要影响，适当降低浇注温度或提高快压射速度均有利于改善铸件的表面质量，减少铸造缺陷、细化晶粒和提高力学性能。对于AZ91D镁合金薄壁手机支架件压铸，合适的浇注温度和快压射速度分别为670 ℃和2.3 m/s，在此工艺参数下生产的铸件表面质量良好，晶粒细小，其平均尺寸仅为5.1 μm，铸件密度高，气孔率仅为2.0%，铸件力学性能优异，其抗拉强度、屈服强度、伸长率和硬度分别为306 MPa、203 MPa、6.0%和86 HV。
关键字: AZ91D镁合金；薄壁件；压铸成形；显微组织；力学性能；数值模拟
（1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Dongguan Eon Technology Co., Ltd., Dongguan 523662, China）
Abstract:The mold filling and solidification process of high pressure die-casting (HPDC) AZ91D magnesium alloy thin-wall phone bracket parts were simulated by Procast software. The effects of the different process parameters on the surface quality, density, microstructure and mechanical properties of thin-wall parts were studied by combining the simulation with experiment. The results show that the type and location of defects are identical with the simulated results. The pouring temperature and fast injection speed have an important effect on HPDC thin-wall parts of AZ91D magnesium alloy. Decreasing the pouring temperature or increasing the fast injection speed properly helps to improve surface quality, decrease casting defects and grain size and increase mechanical properties of parts. For HPDC thin-wall phone bracket parts of AZ91D alloy, suitable pouring temperature and fast injection speed are 670 ℃ and 2.3 m/s, respectively. Under the process parameters, the thin-wall parts have good surface quality, the average size of the grains is only 5.6 μm and the porosity level of the parts is only 2.0%. Also, the mechanical performance of the thin-wall parts is excellent, and the ultimate tensile strength, yield strength, elongation and hardness are 306 MPa，203 MPa，6.0% and 86 HV, respectively.
Key words: AZ91D magnesium alloy; thin-wall part; high pressure die-casting; microstructure; mechanical property; numerical simulation
