Effect of material form on deposition characteristics in micro-plasma transferred arc additive manufacturing process

Abstract

This paper presents study on influence of different forms (i.e. powder, wire, and combined powder-wire) of Stellite-6 deposition material on arc interaction and deposition characteristics in μ-plasma transferred arc additive manufacturing (μ-PTAAM) process. It was found that (i) width of μ-plasma arc remains almost constant throughout its length for the powdered form, but it varies for wire and combined powder-wire form; (ii) the wire form resulted in the highest deposition efficiency (94.9%), substrate temperature (114.7 °C) and surface roughness (202 μm) whereas the powder form gave the highest average value of dilution (10.3%) and microhardness (588 HV), lowest substrate temperature (70.9 °C) and surface roughness (125 μm), and smallest grain size (3 μm); (iii) combined powder-wire form gave the lowest dilution (8.66%) and microhardness (534 HV), and largest grain size (7 μm); (iv) elemental composition analysis found highest inclusion of iron for the powder form; (v) phase analysis revealed that different forms of deposition material yielded same crystalline phases. This study proves that different forms of the deposition material can be used in μ-PTAAM process and combined powder-wire form the deposition material narrows the existing gaps between the wire and powder forms for various aspects of additive manufacturing. © 2020 CIRP