Precipitate processes in Mg-5Al magnesium alloy

In this article, the impact of long-term annealing on transformation of microstructure, in sand casting and die-casting Mg-5Al magnesium alloy was discussed. The Mg₁₇Al₁₂ phase of the diverse morphology is the basic strengthening phase in Mg-5Al alloys. After sand casting microstructure of Mg-5Al alloy consists of α-Mg solid solution with continuous and discontinuous precipitates of Mg₁₇Al₁₂ phase. After die-casting, the structure is characterized by significant grain refining of α-Mg solid solution, however Mg₁₇Al₁₂ phase, together with α-Mg solid solution, forms fully divorced eutectic. The Mg₁₇Al₁₂ phase undergo decomposition and coagulation at the temperature above 180°C and higher.