Tandem rapid manufacturing of Inconel-625 using laser assisted and plasma transferred arc depositions

This paper presents an investigation on deposition of Inconel-625 using laser rapid manufacturing (LRM) and plasma transferred arc (PTA) deposition in individual and tandem mode. LRM has advantages in terms of dimensional accuracy, improved mechanical properties, finer process control, reduced heat input and lower thermal distortion, while PTA scores more in terms of lower initial investment, lower running cost and higher deposition rate. To quantify the clubbed advantages and limitations of both processes, these were studied individually and in tandem. A number of samples were deposited at different process parameters like power, scan speed, powder feed rate. They were subjected to tensile test, adhesion-cohesion test, impact test and micro hardness measurement. The results of individual tests showed the comparable mechanical properties with +/- 20% variation. The mixed dendritic-cellular and dendritic-columnar microstructures were respectively observed for LRM and PTA deposits with a distinct interface for the case of tandem deposition. The interface strength of tandem deposits was evaluated employing adhesion-cohesion test, and it was found to be (325 +/- 35) MPa. The study confirmed the viability of LRM and PTA deposition in tandem for hybrid manufacturing.