Die-casting effect on surface characteristics of thin-walled AZ91D magnesium components

Filling trace, filling time and temperature distribution during the die-casting process were simulated using commercial software (MAGMA). The surface microstructure and phase distribution in thin-walled AZ91D magnesium components cast on a hot-chamber die-casting machine were investigated by means of optical microscopy and scanning electron microscopy. The depth profile of alloying elements was examined using a glow discharge optical emission spectrometer. The outer skin microstructure consists of more β-phase and less eutectic α-phase than the interior region. The elemental content of C, Si, and Fe in the outer skin increased along the filling trace, and they decreased with increasing distance from the surface to the interior region, while the Al had an inverse trend. The corrosion resistance decreased along the filling trace.