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

• Main Authors: LIU Zhan-yong, ZUO Xiao-qing, ZHONG Zi-long, LI Wei-wei
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2017-06-01
• Series: Journal of Materials Engineering
• Subjects: ZA27 alloy; Sc modification; semi-solid thixo-extrusion; microstructure; mechanical property
• Online Access: http://jme.biam.ac.cn/CN/Y2017/V45/I6/17

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 alloys 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 the globular grains is obtained by Sc modification combined with semi-solid thixo-extrusion. The microstructure of ZA27 alloy by semi-solid thixo-extrusion combined with T6 heat treatment is composed of small α primary phase and (α+η) eutectoid phase, which shows that semi-solid thixo-extrusion can promote the dissolution of ε phase and reduce (β+η+ε) ternary eutectic content. The mechanical properties 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.