Microstructural Evolution During Homogenization Heat Treatment of AA 6063 Alloy in Batch and Continuous Furnaces

Homogenization heat treatment after casting is performed to eliminate the dendritic segregation and coarse eutectic intermetallic phases since they reduce the fracture toughness of aluminium alloys. By the homogenization treatment, β-AlFeSi can be converted to more spherical α-AlFeSi particles. The β → α transition is crucial because the β-AlFeSi particles cause a number of surface defects and limit the extrudability. Also, the rate of cooling in the homogenization furnace is one of the critical influencing factors on the size of the Mg₂Si precipitates which affect the mechanical properties positively. In this study, billets of AA 6063 from the same cast were put through homogenization heat treatment by using batch-type and continuous furnaces. The solution, quenching, and aging heat treatment were applied to each sample. Microstructural characterization by SEM and the hardness test were conducted to understand the effects of the furnace type on the mechanical properties of aged AA 6063 aluminium.