Effect of Zn Content on the Mechanical Properties of Nemalloy–Al-Fe(Zn, Mg) Alloys for Automotive Applications

In comparison with mainstream Al-Si alloys for structural die-casting components for automotive applications, Nemalloy HE700 (Al-Fe(Zn,Mg)) offers higher strength-to-weight ratio and elongation even without heat treatment. It is a newly developed Al-Fe hypoeutectic-based alloy with Zn and Mg additions serving as precipitation strengtheners. This study aims to determine the effect of Zn content on the microstructure and attendant mechanical properties of HE700. Alloy variations were casted as plates with three different thicknesses using high-vacuum high-pressure die casting with four different weight percentages (5%, 6.25%, 7.5%, and 8.75%) of Zn and a fixed weight percentage of Mg (1%). Mechanical properties were determined using uniaxial tensile measurements as a function of natural ageing time out to 14 days. It is observed that as zinc content increases, the electrical conductivity increases and hardness decreases. Alloy with 6.25% Zn showed better elongation (13.5%) compared to the other alloys at the end of 14 days of natural ageing but Alloy with 8.75% Zn shows better yield strength (218 MPa).