Prediction of solidification structure in the laser metal deposition of IN625 superalloy using the numerical and experimental techniques

Extensive research has been conducted in the field of direct laser deposition (DLD) process simulation. In this study, the finite volume method was used to predict the solidification microstructure and melt pool status in the IN625 cladding process. By fitting the data and matching the Hunt-Fleming relationship, the values of a=29.1827 and n=0.354 were obtained. A columnar structure was observed near the G/R=1.4e6 line, a combination of columnar and equiaxed structures between the G/R=1.4e6 and G/R=0.3e6 lines, and a fully equiaxed structure at points below the G/R=0.3e6 line. Finally, using the RSM method, a suitable area for achieving directional solidification (columnar dendrite with minimum orientation), with a power of more than 225 W and a powder/scan speed ratio (F/S) of less than 40 mg/mm, was determined.