本文论述了镁合金材料的性能及特点，详细介绍了镁合金的成形工艺，包括压铸、熔模铸造、消失模铸造、塑性成形、超塑性成形和半固态成形技术。接着介绍了一种新的铸造技术-真空低压消失模铸造的工作原理。建立了其在充型过程中的物理模型，分析了其铸造的工艺特点及影响因素，以及在铸造高精度、复杂镁合金铸件方面的优势。真空低压消失模铸造新技术在铸造高质量和高精度的镁合金铸件中具有广泛的应用前景。采用窗体及电机壳体模样测试了AZ91D 镁合金在该工艺条件下的充型能力。研究表明：充型气体的气压与流量、泡沫模样的密度与裂解特性、涂层厚度及透气性、浇注温度、真空度等是镁合金真空低压消失模铸造过程中的主要影响因素。窗体和电机壳体成功浇注试验证明了真空低压消失模铸造新工艺大大提高了镁合金的充型能力,消除了重力下消失模铸造镁合金充型能力差、易形成浇不足和冷隔缺陷的缺点。最后对目前镁合金生产中存在的问题及解决方法进行了讨论，并展望了其发展前景。
关键词：镁合金；成型方法；真空低压消失模铸造；充型能力；影响因素
Abstract
In this paper, the properties and characteristics of magnesium alloys are discussed in the first，The forming technologies of magnesium alloy are described including die-cast，investment-casting，full-mold casting，plastic forming and semi-solid forming technologies．Then a new expendable pattern casting (EPC) process, with vacuum and low pressure, was introduced, its working principle and affecting factors were analyzed, and the filling mould physical were built. The advantages were also shown in casting high precision and complex magnesium alloy parts，the process possesses wide applications for casting high quality and complex parts as the replenishment of die casting process and low pressure casting process.
The filling ability of AZ91D magnesium alloy was examined with electromotor frame and window pattern via this process. The experimental results indicate that main casting process parameters contain pressure and flux of filling gas, pyrolysis characteristics and density of foam pattern, thickness and permeability of coating, pouring temperature and vacuum degree. The success of ca sting motor shell and window pattern demonstrates the new technology can greatly improve the filling ability of the magnesium alloy, consequently eliminates the misrun and cold shut in gravity LFC process. Finally the present question of magnesium industry and its solution are discussed also，and its future is prospected．
key words: magnesium alloys; forming technology；low-pressure expendable pattern casting; Filling ability; Influencing factors
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