High productivity themed fabrication of Haynes 282 using laser powder bed fusion: Processing, microstructure and mechanical properties

Laser interaction of Haynes 282 (H282), a nickel-based superalloy renowned for its application in the turbine exhaust sections of aero engines and in advanced ultra-supercritical boilers, is explored to increase productivity through laser powder bed fusion (PBF-LB) process. Currently, PBF-LB processes typically employ 20-40μm layer thickness for this alloy. This study aims to determine the suitable process parameter variations, to reduce the build time to half, through focus offset and higher (60μm and 90μm) layer thickness. Single and multi-track laser experiments without powder were performed on a wrought H282 plate over a wide range of power and speed permissible in PBF-LB process machine, for building test blanks with optimized parameters. Laser focus offset effect on melting and melt pool dimensions were analysed. Effect of power, speed and hatch distance on melt pool behaviour and dimensions are characterized, with high power resulting in deeper melt pool and slower speed resulting in wider melt pool. Effect of change in melting mode due to offset of laser focal plane with respect to build plate is discussed. The feasibility of building 110 mm tall build with 60μm and 90μm layer thickness with ~40-60% reduction in build time compared to standard process parameters, is presented with microstructural and mechanical characterization.