Crystal-Grain Refinement of Materials under an Ultra-Strong Gravitational Field

In this study, we investigate the crystalline states and conditions for the grain-refinement of Bi70Sb30 (at.%) alloy. It was considered under an ultra strong gravity field, the crystals were fine-grained from the primary grain sizes of several mm to several tens of mm, and the crystal growth followed with formation of graded-composition structure due to sedimentation of atoms along the direction of gravity. It was found that for the crystal-grain refinement in Bi70Sb30 alloy the minimum gravitational field and the minimum time duration were at least 160,000 G and 10 hours, respectively at about 200 °C.