The Effect of Sintering and Compaction Conditions on the Microstructure and Properties of AZ31 Magnesium Alloy

Magnesium and its alloys are attractive materials in industrial applications due to the low density and high strength. The properties of AZ31 magnesium alloy can be much improved by choosing proper sintering conditions. In this study, the microstructure and mechanical properties of AZ31 prepared by mechanical alloying, compaction, and sintering of elemental powder, were studied. The effect of parameters such as compaction pressure, heating rate, and sintering time were investigated to determine the optimal sintering condition of AZ31 magnesium alloys. Previous researches have focused on the specific conditions of sintering, while in this study, various factors of sintering were examined simultaneously. The results showed that sintering time is one of the major variables that have a considerable effect on the final properties of AZ31. In short sintering times, recrystallization leads to small grain formation inside the powder. However, as the sintering time increases, the growth of new grains slows down and no trace of them can be detected in the microstructure. Furthermore, the conditions for recrystallization were also determined, which can be used to provide small grain size and, consequently, better properties after the initial powder milling and sintering. At optimal sintering conditions, the average grain size, porosity percentage and hardness of the samples AZ31 magnesium alloy were obtained as 104 µm and 2.05%, and 79.5 HV, respectively which is expectable result in comparison to the bulk AZ31.