Influence of Semisolid and Strontium Addition on Dry Sliding Wear Behavior of Hypoeutectic Al-Si Alloy

The study aims to investigate the effect of semisolid structure and strontium (Sr) addition on the wear behavior of hypoeutectic Al-Si alloy. Semisolid hypoeutectic Al-Si alloy was prepared using cooling slope casting with addition of 0 to 0.93 wt.% Sr. Microstructural study was done using an optical microscope. Vicker microhardness and pin on disc tribometer were used for microhardness and wear testing. When compared to conventional casting, the microhardness of the semisolid hypoeutectic Al-Si alloy improved by 9.8%. Sr addition at 0.43 wt.% resulted in a refined eutectic structure with a 17% increase in hardness over conventional casting. The globular structure α-Al formed during semisolid casting reduced porosity, and the addition of Sr refined the eutectic silicon into a fine fibrous structure that is tightly bound with the Al matrix. These are the primary factors that contribute to the high wear resistance in modified-Sr semisolid alloys.