EFFECT OF IRON AND COMBINED IRON AND BERYLLIUM ADDITIONS ON THE FRACTURE-TOUGHNESS AND MICROSTRUCTURES OF SQUEEZE-CAST AL-7SI-0.3MG ALLOY

Squeeze casting is a near-net-shape process of casting under pressure that yields a fine-grain structure with-higher density and mechanical properties compared to conventional casting processes, Iron is the mos t commonly present impurity element in Al-7Si-0.3Mg, the alloy investi gated, An increase in iron content significantly decreases fracture to ughness, However, trace additions of beryllium completely neutralize t he detrimental effect of iron, The variables of the squeeze casting pr ocess greatly govern the microstructures and macrostructures and thus the defects in the casting. This case study deals with Al-7Si-0.3Mg sq ueeze-cast cranks with four major defects - blistering, debonding, por osity, and patches of silicon segregation on the casting surface - and the appropriate remedial measures to eliminate these defects.