Coarse Columnar Dendrites of GH3039 Nickel-Based Alloy at Diverging Grain Boundaries during Wire and Laser Additive Manufacturing: A Phase Field Simulation

Coarse columnar dendrite greatly reduced the mechanical performance of GH3039 nickel-based alloy in the additive manufactured parts, which limited its application in the engineering fields. This study provides a comparison of overgrowth behaviors at diverging grain boundaries through two-dimensional phase field simulation, and the effect of dendrite orientation on overgrowth behavior was analyzed. Moreover, our results show that the primary spacing becomes larger as the increasing of dendrite orientation. The columnar dendrites branch new dendrites near grain boundaries to refine the primary arm spacing in the process of wire and laser additive manufacturing (WLAM).