ALLOY CONTAINING IRON-RICH INTERMETALLICS

In this research the effect of semi-solid heat treatment on matrix structure and iron-rich intermetallics of hyper-eutectic Al-18 % Si containing 0.95%Fe is studied. Semi-solid heat treatment at heating temperature of 585 C shows a significant refinement of iron-rich intermetallic phase. In as cast samples,needle-like iron-rich intermetallics phases was observed, otherwise, plate-like and fine plate-like iron-rich intermetallics phases was observed for all samples heat treated in semi-solid state. Hardness values for semi-solid heat treated Al-18 % Si Alloy for all heating time range (10-40 min) are relatively higher compared with the as cast one. Hardness value of 72.5 HRB is achieved by heating Al-18 % Si alloy at heating temperature of 585 C for 20 min. At the early stages of heating time (up to 20 min), a significant decreases of weight loss is observed in Al-18 % Si alloy when semi-solid isothermal heat treatment was applied at 585 C heating temperature. However, semi-solid isothermal heat treatment performed above heating time of 25 min might result in increases of weight. The optimum semi-solid heating treatment condition wa