Surface oxidation phenomenon of Mg–10 wt% Sn–1.5 wt% Al alloy during homogenization

Abstract

Homogenization heat treatment of Mg–10 wt% Sn–1.5 wt% Al alloy is studied. The results show that aliquid phase begins to form in the alloy at the temperature (Tm) of 550.2 °C, so the homogenization is performed at 460 °C–510 °C, based on the empirical formula T= (0.9–0.95) Tm. But the surface oxidation phenomenon takes place when treating at 460 °C, which makes the progress of the process difficult to accomplish. Metallograph depicts that wetting phase transformation emerges during the process. For further researching, vacuum quartz tube experiment is conducted, which indicates that the phenomenon is contact with the wetting phase transformation of grain boundaries (GBs) and grain-boundary triple junctions (GB TJs).