Effects of buoyancy convection on phase morphology during solidification of Pd40Ni40P20 alloy

Samples of Pd40Ni40P20 alloy were solidified both on the ground and on board a Chinese Retrievable Satellite in order to study the effects of gravity-induced convection on the phase morphology. In comparison to the secondary dendritic spacing, the effective mass transport coefficient under normal gravity condition was estimated to be 1.95 times as high as that under microgravity conditions at the cooling rate of 0.056 K s−1. The higher mass transport coefficient value due to the existence of buoyancy convection on the ground led to the formation of coarser dendrites of the primary phase Ni5P2 in the ground-based sample.