Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Metallurgical Engineering

Hypereutectic alloys such as B390 alloy exhibit very specific and interesting properties, such as high wear resistance, high strength and hardness, and low thermal expansion coefficients. As a result, they are used in heavy wear applications, often at elevated or medium temperatures, such as in pistons, cylinder blocks and AC compressors. However, their use has always been handicapped by several difficulties: in particular, their high latent heat and consequent long solidification time resulting in die wear, difficulty in avoiding segregation of massive primary silicon particles, and generally their unfavorable shrinkage behavior. In this study SSM and ultrasonic treatment should overcome most of these difficulties. In the first, the ultrasonic treatment most of the silicon plates were disconnected and broken, forming spheroidized crystals. In the second, to study the thixotropic behavior ultrasonically treated and non-treated specimens were used under semi-solid conditions. Semi-solid materials (SSM) are now becoming increasingly popular for the manufacturing of automotive parts

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