Effects of Pressure on Microstructure and Residual Stresses during Hot Isostatic Pressing Post Treatment of AISI M50 Produced by Laser Powder-Bed Fusion

Laser powder-bed fusion (LPBF) enables the production of difficult-to-machine materials with near-net shape and complex geometries. Components made tool steels produced by LPBF, even using high preheating temperature, tend to show residual porosity, cracks, stresses. Hot isostatic pressing (HIP) is able densify components modify their microstructure. Moreover, compared conventional heat treatment at ambient pressure, rapid cooling within HIP vessel can alleviate thermal stresses, warping or cracking during quenching. In this study, effects pressure on microstructure evolution stresses are investigated. Samples were LPBF. Partly, they conventionally treated austenitizing, quenching, tempering, partly a HIP-device an integrated quenching facility. The was characterized optical microscopy, scanning electron microscopy employing energy-dispersive X-ray spectroscopy, diffraction analysis. results showed that besides densification material porosity 0.001%, influenced retarding recrystallization austenitization due led slight compressive around 11 MPa surface components.