Formation of stray grains during directional solidification of a superalloy AM3

Stray grains were found during the preparation of single crystal superalloy AM3 by seeding technique and the researching on the competitive growth of bi-crystal. Stray grains were mainly observed at the diverging 〈001〉 corner of the mold wall. Therefore, increasing orientation deviation angle would intensify the possibility of the formation of stray grains. This was because the solute was inclined to enrich at the diverging 〈001〉 corner of mold wall, leading to the relatively large undercooling, and accordingly resulted in the formation of stray grains.