Effects of Hot Spinning and Heat Treatment on the Microstructure, Texture, and Mechanical Properties of A356 Wheel Hubs

Abstract

The effects of hot spinning and heat treatment on the microstructure, texture, and mechanical properties of A356 wheel hubs were studied. The results of the microstructure investigation show that the as-cast microstructure was broken and elongated after spinning, but the microstructure in the inner layer was not substantially streamlined. The results obtained for the eutectic Si particles reveal that they were partially cracked under the action of the spinning stress, resulting in a slight decrease in size. The spheroidization effect of heat treatment on the eutectic Si particles was significant. The results of texture research show that the original as-cast texture disappeared after spinning, and the subsequent heat treatment had an influence on the texture transformation. The distribution of the misorientation angle changed after hot spinning and heat treatment. The hardness results show that the hardness decreased slightly by spinning but increased with the subsequent heat treatment. Both spinning and heat treatment could improve the tensile strength, but the tensile strength of the inner layer was lower than that of the outer layer. The effect of the developed textures on the yield strength was explored by a comparison study using the Schmid Factor.