Microstructure Evaluation of Direct Metal Laser Sintered SS316L - MWCNT Composite

Metal matrix composite comprising of Stainless Steel SS316L reinforced with Multi-walled carbon nanotubes has been developed by laser assisted process. Pure electroless Ni coating was done to enhance wettability of CNTs. Double cone blender was used to obtain homogeneous mixture of electroless Ni coated MWCNTs in different vol. % and SS316L powder. Test specimens were fabricated at various laser scan speeds. Morphology and Microstructure studies were conducted by using Optical Microscopy, X-ray diffraction, FESEM, and EDS. Electroless Ni coating was evaluated for surface morphology and elemental composition. The effect of laser scan speed and CNT vol.% content on solidification and microstructure changes has been investigated. SEM microstructures of tensile fractured surface of composite have been studied for wetting behaviour and survival of CNTs under high temperature processing. Ni coated MWCNT could be a promising reinforcing nano material for developing high strength and low weight MMCs.