Development of Laser Powder Bed Fusion Processing Parameters for Aermet 100 Powder

Aermet 100 is a high-alloy steel with exceptional fracture toughness (minimum 110 MPa-m(.5)) and high strength-to-weight ratio. It also has good weldability. Therefore, it is good candidate material for the laser powder bed fusion process (L-PBF). L-PBF parameters were optimized for high density according to image analysis and Archimedes' principle. Then, tensile testing was performed on specimens made with the parameters which produced high density. After the process parameters and heat treatment were optimized, the tensile and yield strength of the specimens met the wrought requirement. However, ductility was much lower than typical wrought, although it was near the minimum requirement. There were random defects which exceeded 100 microns on the fracture surface of the tensile specimens and in the microstructure. The defects are likely attributed to the large and irregularly shaped powder particles which can effect powder packing and increase spatter formation.