Effect of Heat Treatment on the Mechanical Properties of Squeeze-Cast Al–5Si–3Cu Alloy for Automotive Applications

Abstract

Al–Si–Cu alloy (A319) castings are used in vehicle industry due to its better castability, high specific strength, corrosion resistance and low cost. Using this alloy, most of the automotive components are manufactured by gravity die casting or high-pressure die casting technique, but these castings contain higher porosity leading to rejections. Squeeze casting is an emerging casting technique in which solidification is done under high pressure which overcomes the drawbacks of the gravity and pressure die casting. It offers higher metal yield, minimum porosity and near-net-shaped products with enhanced mechanical properties. Typical Al–Si–Cu cast alloys are heat-treated for T6 condition for attaining tensile strength in the range of 250–300 MPa and elongation up to 3%. The mechanical properties of this alloy can be further improved by the addition of Mg and Sr modification and by subjecting to squeeze casting. The present study deals with the optimization of the heat treatment cycle of squeeze-cast alloy billets and compares squeeze-cast alloy with the gravity-cast alloy in terms of mechanical properties and wear behaviour.