Changes in the structure and properties with overheating of Al?Mg alloys

Abstract

1. Overheating of Al−Mg alloys occurs in two stages. In the early stage micropores are formed in binary alloys, uneven etching decreases, and the boundaries of dendritic cells are revealed in more highly alloyed alloys. In the final stage macropores are observed in binary alloys and melting in more highly alloyed alloys. 2. Heat-treated alloys retain the cast structure. Micropores and macropores are formed in β-phase sites in binary alloys. In more highly alloyed alloys melting occurs in high-etching sections. 3. With overheating the character of the fracture changes from ductile (for quenched alloys) to intercrystalline in the early stage of overheating and mixed (along melted sections) in the later stage of overheating.