AlAl3Ni eutectic alloy and AL/WC(NI) composite directionally solidified under microgravity and normal gravity Original Research Article

Directional solidification of AlAl3Ni eutectic alloy and Al/WC(Ni) composite were performed in the Multi-functional Crystal Growing Furnace on board the unmanned Chinese Shenzhou II spacecraft and on the ground respectively. The microstructures of the samples were investigated applying metallographic, SEM, XRD and image analysis techniques. Many differences were found between the space samples and the ground samples. It could be concluded that gravity condition had a strong influence on the solidification behavior of materials. The temperature gradient driven convection, i.e. Marangoni Convection, played an apparent role on the formation of solidification microstructure under microgravity.