Effects of Solidification Rate on Microstructure and Mechanical Properties of AZ91D Magnesium Alloy

摘要

This study aimed to investigate the change ofmicrostructures and mechanical properties with thesolidification rate of AZ91D magnesium alloy. In order tochange the solidification rate of AZ91D melt, the pouringtemperature and amount of inoculant(C_2Cl_6) were controlledand the permanent mold of cone type was used. Themicrostructure of as-cast specimens was investigated by opticalmicroscope and scanning electron microscope (EDS) analysisand the grain size was measured by planimetric method. Thevariations of hardness and tensile properties on the grain sizewere investigated, and the deformed specimen was observed byTEM. In case the solidification rate was below about 20 deg C /sec, the grain refinement increases markedly as the solidificationrate is increased, but the degree of grain refinement wasdiminished to higher solidification rate. The Hall-Petchrelationship between grain size and hardness, yield strength washeld good and the values of 53.0, 419.6 for #sigma# and k wereobtained, respectively.