Mechanical properties and damping capacity after grain refinement in A356 alloy

JR-6 nano-grain refiner was employed to investigate mechanical properties and damping capacity of A356 alloy after grain refinement. Experimental findings indicate that α-Al dendritic arm spacing reduced from 44 μm to 23 μm in size after grain refinement. With T6 heat treatment, gliding fracture only was observed by SEM on fracture region after refinement, which filled with dimple fully. Tensile testing results show that A356 alloy after refinement has better mechanical properties, which increased by 30 MPa, 24 MPa, 4.1% in tensile strength, yield strength and elongation, respectively. Damping measurement shows damping capacity of A356 alloy after grain refinement is higher than that of without refinement. Moreover, damping capacity increases with increasing the temperature and decreases with increasing frequency. With testing condition of room temperature and frequency of 0.5 Hz damping capacity of A356 alloy after grain refinement is 13 × 10− 3, increased by 5 × 10− 3 compared to A356 without refinement in same case. Also damping mechanisms are discussed basing on experimental results.