Competitive grain growth mechanism in three dimensions during directional solidification of a nickel-based superalloy

Stray grains with random orientations were observed at the diverging 〈0 0 1〉 corner of the mold wall in the directionally solidified single crystal superalloy AM3. An experimental study, together with the simulation of the ProCAST software, was conducted to investigate the mechanism of competitive growth during the directional solidification with bi-crystal. Based on the results of the experiments and simulations, it was proposed that the factor contributing to the competitive growth was the rotation angle of the unfavorably oriented grain.