(1. 沈阳工业大学 材料科学与工程学院，沈阳 110178；
2. 北京航空航天大学 材料科学与工程学院，北京 100083)
摘 要: 采用铜模铸造制备直径为3 mm的Mg70−xZn25Ca5Cux(x=1, 2, 3.5, 5)系列合金。分别采用扫描电镜(SEM)、X射线衍射仪(XRD)、力学性能试验装置研究合金的显微组织、相组成和铸态样品的压缩性能，并对断口形貌进行分析。结果表明：Mg69Zn25Ca5Cu1可以形成直径为3 mm的非晶合金，其强度和塑性应变分别为690 MPa和1.7%。与Mg-Zn-Ca合金相比，其非晶形成能力和塑性应变均有提高。同时这也是目前在直径大于2 mm的Mg基非晶合金中所发现的最大塑性应变量。
关键字: Mg-Zn-Ca合金；Cu；非晶形成能力；力学性能
Mg-Zn-Ca alloys
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178, China;
2. School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics,
Beijing 100083, China）
Abstract: Mg70−xZn25Ca5Cux(x=1, 2, 3.5, 5) as-cast alloys with 3 mm in diameter were produced by using copper mold casting method. The microstructures, phase constitutes and mechanical properties of as-cast samples were investigated by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and compression tester. The fracture surfaces were also analyzed by SEM. The results show that the critical sample size for glass formation, the fracture strength and the plastic strain of Mg69Zn25Ca5Cu1 alloy are 3 mm in diameter, 690 MPa and 1.7%, respectively. Both of the glass forming ability and the plastic deformation are improved obviously compared with Mg-Zn-Ca alloys. Up to now the plastic strain is the largest one in the samples with diameter larger than 2 mm for Mg-based bulk metallic glasses.
Key words: Mg-Zn-Ca alloy; Cu; glass forming ability; mechanical properties
