(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083；
2. 東莞宜安科技有限公司，東莞 523662)
摘 要: 利用Procast模擬軟件分析AZ91D鎂合金薄壁手機(jī)支架件的充型過程與凝固過程；結(jié)合模擬與實(shí)驗(yàn)研究不同工藝參數(shù)對薄壁壓鑄件表面質(zhì)量、密度、組織及力學(xué)性能的影響，并探索出合適的工藝參數(shù)。結(jié)果表明：薄壁支架件所產(chǎn)生的缺陷類型及位置與模擬結(jié)果相吻合；澆注溫度和快壓射速度對薄壁件的壓鑄成形具有重要影響，適當(dāng)降低澆注溫度或提高快壓射速度均有利于改善鑄件的表面質(zhì)量，減少鑄造缺陷、細(xì)化晶粒和提高力學(xué)性能。對于AZ91D鎂合金薄壁手機(jī)支架件壓鑄，合適的澆注溫度和快壓射速度分別為670 ℃和2.3 m/s，在此工藝參數(shù)下生產(chǎn)的鑄件表面質(zhì)量良好，晶粒細(xì)小，其平均尺寸僅為5.1 μm，鑄件密度高，氣孔率僅為2.0%，鑄件力學(xué)性能優(yōu)異，其抗拉強(qiáng)度、屈服強(qiáng)度、伸長率和硬度分別為306 MPa、203 MPa、6.0%和86 HV。
關(guān)鍵字: AZ91D鎂合金；薄壁件；壓鑄成形；顯微組織；力學(xué)性能；數(shù)值模擬
（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
