富铈混合稀土对ZA155高锌镁合金组织和力学性能的影响  

Effect of Ce-Rich Misch Metals Microstructure and Mechanical Properties of ZA155 High Zinc Magnesium Alloy

作　　者：田爱环[1] 张金山[1] 杜二玲[1] 王红霞[1] 周翠兰[1] 

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《铸造》2008年第8期783-787,共5页Foundry

基　　金：国家自然科学基金(50571073);山西省自然科学基金项目(20051052);太原市大学生专项基金项目(07010713)

摘　　要：采用常规铸造方法,向ZA155高锌镁合金熔体中加入适量富铈混合稀土获得了稀土合金化的高锌镁合金。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)/能量散射光谱(EDS)、硬度、冲击韧度以及拉伸性能测试等分析手段研究了混合稀土对高锌镁合金组织与力学性能的影响。结果表明:加入混合稀土后形成高熔点、高热稳定性的针状稀土化合物相(Mg3Al4Zn2RE),改善晶界相的分布状态,阻止晶粒长大,细化结晶组织,提高常高温力学性能。当加入1.5%的混合稀土时,ZA155高锌镁合金室温抗拉强度达到峰值时为203 MPa,比变质前提高了21%,冲击韧度达到峰值时为4.50 J/cm2,比变质前提高了50%。Rare-earth alloyed high zinc magnesium alloy was obtained by adding proper Ce-rich misch metals into high zinc ZA155 magnesium alloy under conventional condition. Effects of Ce-rich misch metals addition levels on the microstructure and mechanical properties of as-cast high zinc magnesium alloy have been systematically investigated by means of optical microscopy, XRD, SEM, EDS, tensile strength test, impact toughness test and hard-meter test. Experimental results indicated that the addition of Ce-rich misch metals into ZA155 magnesium alloy results in the generation of high-melting-point and high thermodynamically stable needle-like Mg3Al4Zn2RE compound, which improved distribution state of the phases at the grain boundary, suppressed the grain growth, refined the solidification microstructure, and finally enhanced the mechanical properties of the alloy at room-temperature and elevated-temperature. When adding 1.5wt.% misch metals into ZA115 magnesium alloy, the room-temperature tensile strength of the alloy reaches 203 MPa, improved by 21%; impact toughness reaches 4.50 J/cm^2, improved by 50%.

关 键 词：富铈混合稀土 高锌镁合金 变质处理 晶粒细化 力学性能 

分 类 号：TG156.9[金属学及工艺—热处理]