Aging and wear characteristics of A356 alloy with Er and Zr addition

The present work investigates the effect of aging on the microstructure, mechanical properties, and wear behaviour of the cast A356 alloy with Er and Zr addition. The aged A356-0.25Zr and A356-0.25Er alloys revealed some but not all of the eutectic and columnar structures. The microstructure of A356, A356-0.5Er, and A356-0.5Er-0.25Zr alloys exhibited large α-Al grains with discrete eutectic silicon. Various intermetallic types and morphologies were observed after the peak aging. The highest hardness (∼120 HV) and the highest tensile strength (∼215 MPa) were achieved in the A356-0.25Zr alloy under peak-aged conditions. The A356 alloy revealed the lowest weight loss and friction coefficient, though it had the least hardness. Delamination was the dominant wear mechanism in all alloys.