Papers by Author: Zhi Fu Sun

Abstract: The microstructures of magnesium alloy AZ91D in as-cast, solid solution and aging conditions were studied by optical, scanning electron and transmission electronic microscopes. The relationship between microstructure and the microhardness was analyzed. It has been found that the microhardness in the matrix varied slightly with the increasing solution time, but increased quickly with the aging time. The difference of the microhardness between the matrix and the second phase in as-cast condition is larger than that in T6 aging condition, because the aluminum-zinc-magnesium (poor) phase existed in the as-cast condition.

Abstract: Flame spray method was used to prepare the Al-Al2O3/TiO2 gradient coating on AZ91D magnesium alloy surface, where diffusion treatment for 2 hours at 380～420 °C was needed to reinforce the binding strength between the coating and the substrate. Appearance and compositions of the coating were analyzed by scanning electronic microscope (SEM) and electron probe microanalysis (EPMA), and the thermal shock resistance and wear resistance of the coating were tested. The result shows: Al-Mg diffusion is produced between the coating and the substrate, for good metallurgy; coating acquires high hardness and resistant to wear and thermal shock.