Differential Thermal Analysis and Microstructure Evolution of AZ61 Mg Alloy

The phase transition temperature point and the solidification microstructure characteristics of AZ61 magnesium alloy were studied by using differential thermal analysis,and the evolution mechanism of the solidification microstructure was analyzed in theory.The results show that the solid-liquid transition temperature of AZ61 magnesium alloy is between 587.10 ℃ to 608.43 ℃,and its eutectic transition temperature is around 413℃;during the solidification of AZ61 magnesium alloy,at first α-Mg dendrites are precipitated,Al-rich residual liquid eutectic transformation occurs at the dendrite clearance,which finally solidify to the α-Mg + β-Mg17Al12 eutectic phase;the nucleation and growth up of eutectic α-Mg phase is often depended on the α-Mg primary phase,and the divorced eutectic forms through pushing β-Mg17Al12 dendrite to the α-Mg grain boundary.