Grain Growth Behavior of AlMg5 Alloy Fabricated by Using a New Mg Mother Alloy Containing Al2Ca during Homogenization and Hot Compression

Grain growth behavior of AlMg5 alloy fabricated by using a new Mg mother alloy containing Al2Ca (referred to as AlMg5-Al2Ca hereinafter) was investigated during homogenization and subsequent hot compression test. Normal AlMg5 alloy using a commercial Mg mother alloy showed abnormally grown large grains in its microstructure after homogenization at 520 ̊C for 12hrs, while the grain growth in the AlMg5-Al2Ca alloy was completely suppressed by formation of stable Al4Ca during solidification on grain boundary. The compressive flow stress of normal AlMg5 alloy at 400 ̊C was significantly increased after homogenization because of lack of grains having proper slip directions to the applied load. But the flow stress of AlMg5-Al2Ca alloy showing no grain growth during homogenization was slightly decreased implying lower energy needed for subsequent thermo-mechanical processing.