Mg-Bi合金的显微组织和力学性能  

Microstructure and Mechanical Properties of Mg-Bi Alloys

作　　者：赵玉华[1] 王猛[1] 

机构地区：[1]沈阳航空航天大学材料科学与工程学院,辽宁沈阳110136

出　　处：《铸造》2012年第7期758-763,共6页Foundry

摘　　要：采用挤压铸造和挤压变形工艺制备了Mg-Bi二元合金,通过金相显微镜分析,室温拉伸性能测试,X射线衍射分析,SEM和EDS等手段,研究了Mg-Bi合金在铸态和热挤压态的显微组织和力学性能。结果表明:铸态Mg-Bi合金随着Bi含量的增加,伸长率逐渐降低,抗拉强度逐渐增加,当Bi含量达10wt.%以上,抗拉强度降低;Mg-Bi合金铸锭经450℃、3 h保温,挤压比为12.76热挤压后,随Bi含量的增加,抗拉强度与伸长率均逐渐增加,当Bi含量达12wt.%时,抗拉强度为219.68 MPa,伸长率为13.43%,Bi含量继续增加,合金抗拉强度及伸长率呈下降趋势;挤压态Mg-Bi合金的力学性能是晶粒细化与Mg3Bi2相综合作用的结果,当Bi含量大于12wt.%后,形成较多粗大的Mg3Bi2相是导致合金力学性能下降的主要原因。Mg-Bi binary alloys are prepared by squeezing casting and extrusion deformation, and their microstructures and mechanical properties under as-cast and as-extruded conditions are investigated by optical microscopy （OM）, tension test at room temperature, X-ray diffraction （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. The results show that the elongation of as-cast Mg-Bi alloy reduces and the ultimate tensile strength increases gradually with the increase of Bi content, while the content of Bi reaches up to 10wt.%, the ultimate tensile strength of alloy starts to reduce. After extrusion at 450℃ for 3 h with extrusion ratio 12.76, the ultimate tensile strength and the elongation of Mg-Bi alloy increase gradually with the increase of Bi content, when the content of Bi is up to 12wt.%, it＇s ultimate tensile strength is 219.68 MPa, the elongation is 13.43%. The mechanical properties of as-extruded Mg-Bi alloys depend on grain refinement and the strengthening of Mg3Bi2 phase. When the content of Bi is up to 12wt.%, the mechanical properties of alloy reduce due to the formation of many coarse Mg3Bi2 phases.

关 键 词：Mg-Bi合金 挤压铸造 热挤压 显微组织 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]