(上海交通大学 金属基复合材料国家重点实验室，
上海 200030)
摘 要: 开发了一种新型的Mg-Zn-Si-Ca合金， 研究了新合金的组织与力学性能之间的关系。 研究结果表明， Mg-6Zn-1Si合金有较好的综合力学性能。 但是由于合金中的主要强化相Mg2Si呈粗大的汉字状，分布于晶界周围， 在受到应力作用时， 这种汉字状相与基体的界面处容易产生微裂纹， 降低合金的抗拉强度、塑性等力学性能。 在Mg-6Zn-1Si合金中加入微量Ca后， 合金的组织得到明显细化， 并使Mg2Si强化相形貌由粗大的汉字状转变为细小、弥散分布的颗粒状。由于显微组织的改善， 使得Mg-6Zn-1Si合金的室温和高温力学性能均有一定的提高。
关键字: Mg-Zn-Si-Ca合金； 显微组织； 力学性能
heat resistant Mg-Zn-Si-Ca alloy
（State Key Laboratory of Metal Matrix Composites,
Shanghai Jiaotong University,
Shanghai 200030，China）
Abstract:A new type of Mg-Zn-Si-Ca magnesium alloy was developed and the correlation between the microstructure and mechanical properties was studied. The results show that the main strengthening phase Mg2Si presents as coarse Chinese script distributed around the grain boundary after adding 1%Si(mass fraction) to Mg-Zn alloys. Under stress the microcrack prefers to occur in the interface between the phase Mg2Si and the matrix. The addition of small amount of Ca to Mg-6Zn-1Si alloys results in refinement of microstructure and the changing of morphology of Mg2Si phases from coarse Chinese script shape to the fine polygonal shape. Owing to the improvement of microstructure, the mechanical properties of Mg-6Zn-1Si alloys at both ambient and elevated temperatures are increased.
Key words: Mg-Zn-Si-Ca alloys; microstructure; mechanical properties
