Corrosion Resistance of Laser Powder Bed Fusion Built Fe-Cr-Mn-Si-W-Mo-B-C Alloy

Abstract

Metal additive manufacturing technology of layer-wise stacking of 2 dimensional patterns is emerging in engineering components manufacturing. Nevertheless, limited materials selectivity is a critical hurdle for industrial adoption. Hard engineering components are good market penetration point because product design is limited by machining cost. Near net shaped product with complex design will be advantageous though net shape products cannot be manufactured by current state AM technology. In this context, applicability of a Fe base powder with multiple components for laser powder bed fusion AM was assessed. Powder layer was pre-placed on STS build platform and layer thickness was set to be 25 um. 2 dimensional patterns were overlaid according to continuous irradiation mode with outer contour formation. Laser input parameters were selected from pre-screening step with 5x5x3 mm3 model. After that, 10x10x10 mm3 samples were prepared with laser powder and laser scan rate changing. According to laser parameters, phase compositions and microstructures were reported. Optimum process window for the powder feedstock is reported. With respects to formation of defects such as distortion, interlayer debonding, cracking, and pores, solidification crack, non-uniformity of powder layer, and primitive bead characteristics were considered. In addition, effects of phase composition on corrosion behavior were investigated by anodic polarization.