半固态触变挤压对ZA27合金组织和力学性能的影响  

Effect of Semi-solid Thixo-extrusion on Microstructures and Mechanical Properties of ZA27 Alloy

作　　者：刘占勇[1] 左孝青[1] 钟子龙[1] 李威威[1] 

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093

出　　处：《材料工程》2017年第6期17-23,共7页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(51164019);云南省应用基础研究重点项目资助(2010CC004);昆明理工大学创新团队项目资助(2010-2015)

摘　　要：通过与常规铸造方法的比较,研究半固态触变挤压对ZA27合金变质、热处理组织和力学性能的影响。结果表明:半固态挤压态合金的密度较铸态合金提高了3%,合金经Sc变质或者半固态挤压都获得了细小而均匀的近似球状组织,而Sc变质结合半固态挤压的球状组织具有最高的圆整度;经T6热处理的半固态挤压合金由细小的初生α相和共析(α+η)组织组成,说明半固态挤压可促进ε相溶解、减少三元共晶(β+η+ε)组织的含量。力学性能测试表明,ZA27合金经半固态挤压+Sc变质+T6热处理后其抗拉强度,伸长率和布氏硬度分别达到586.01MPa,17.57%及171HB。Through comparative study with normal casting, the effects of semi-solid thixo-extrusion on microstructures and mechanical properties with modification treatment and heat treatment of ZA27 al- loys were studied. The results show that the density of semi-solid thixo-extrusion ZA27 alloy increases by 3% compared to the one obtained by normal casting, fine spherical uniform microstructure is obtained by Sc modification treatment or semi-solid thixo-extrusion, and the best roundness of theglobular grains is obtained by Sc modification combined with semi-solid thixo-extrusion. The micro- structure of ZA27 alloy by semi-solid thixo-extrusion combined with T6 heat treatment is composed ofsmall a primary phase and （α＋η） eutectoid phase, which shows that semi-solid thixo-extrusion canpromote the dissolution of ε phase and reduce （β＋η＋ε） ternary eutectic content. The mechanicalproperties test indicates that the tensile strength, elongation and Brinell hardness of the ZA27 alloy by semi-solid thixo-extrusion, and after Sc modification and T6 heat treatment, are up to 586.01MPa, 17.57% and 171HB respectively.

关 键 词：ZA27合金 Sc变质 半固态触变挤压 微观组织 力学性能 

分 类 号：TG249.2[金属学及工艺—铸造]