Microstructural evolution and phase transformation during partial remelting of in-situ Mg2Sip/AM60B composite

作者：Zhang, Su-qing; Chen, Ti-jun^*; Cheng, Fa-liang; Li, Lei-liang

来源：Transactions of Nonferrous Metals Society of China, 2016, 26(6): 1564-1573.

DOI：10.1016/S1003-6326(16)64262-0

• magnesium alloy
• partial remelting
• thixoforming
• microstructure evolution
• phase transformation
• in-situ composite

The microstructural evolution and phase transformations during partial remelting of in-situ Mg2Sip/AM60B composite modified by SiC and Sr were investigated. The results indicate that SiC and Sr are effective for refining primary alpha-Mg grains and Mg2Si particles. After being partially remelted, a semisolid microstructure with small and spheroidal primary alpha-Mg particles can be obtained. The microstructural evolution during partial remelting can be divided into four stages: the initial rapid coarsening, structural separation, spheroidization and final coarsening, which are essentially caused by the phase transformations of beta ->alpha, alpha+beta -> L and alpha -> L, alpha -> L, and alpha -> L and L -> a, respectively. The Mg2Si particles have not obvious effect on the general microstructural evolution steps, but can slower the evolution progress and change the coarsening mechanism. During partial remelting, Mg2Si particles first become blunt and then become spheroidal because of melting of their edges and corners, and finally are coarsened owing to Ostwald ripening.

• 出版日期2016-6
• 单位兰州理工大学