J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (7): 1149-1161.DOI: 10.1016/j.jmst.2017.11.044

• Orginal Article • Previous Articles     Next Articles

Partial melting behavior and thixoforming properties of extruded magnesium alloy AZ91 with and without addition of SiC particles with a volume fraction of 15%

Yu-Shi Yia, Yi Mengab(), Dan-Qing Lia, Sumio Sugiyamac, Jun Yanagimotoc   

  1. aCollege of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
    bNational Engineering Research Center for Magnesium Alloys, Chongqing 400044, China
    cInstitute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
  • Received:2017-10-08 Revised:2017-11-10 Accepted:2017-11-16 Online:2018-07-10 Published:2018-07-22

Abstract:

A series of reheating-isothermal holding experiments and compression tests were conducted on pristine magnesium alloy AZ91 extruded by equal channel angular extrusion (ECAE) and SiC particles (a volume fraction of 15%) reinforced AZ91 composite (AZ91-SiCp) by regular extrusion. Dissolution of eutectic compounds and partial melting of the α-Mg matrix occurred during the reheating of these materials. Spherical semisolid slurries of these materials were obtained when the reheating temperature and isothermal holding time were 550 °C and 20 s, respectively. The presence of SiCp in AZ91-SiCp not only caused lower liquid fractions of semisolid slurries but also resulted in higher values of flow stress during semisolid compression tests. Both AZ91 alloy and AZ91-SiCp composite exhibited better thixoforming properties at high temperatures. Segregation of SiCp did not occur during thixoforming of AZ91-SiCp composite after an isothermal holding at semisolid temperatures for 20 s.

Key words: Semisolid forming, Metal matrix composites, Magnesium alloy, Microstructural evolution