Role of heat treatment conditions in the high-temperature deformation behavior of laser-powder bed fused Fe-Cr-Ni-Al maraging stainless steel

The present research investigates the high-temperature behavior of laser powder bed fused (LPBF) Fe-Cr-Ni-Al maraging stainless steel (equivalent to PH13-8Mo). Fully dense PH13-8Mo samples are printed using an EOS M290 printer, and the effect of different heat treatments on high-temperature behavior and microstructure development is investigated. The material is studied under as-printed (AP), austenitized aged (AA, austenitized at 900 degrees C for 1 h followed by aging at 530 degrees C for 3 h), and direct-aged (DA, aged at 530 degrees C for 3 h) conditions. Uniaxial compression tests are conducted using a Gleeble (R) 3500 thermal-mechanical simulator at 400 degrees C and 500 degrees C at a quasi-static strain rate of 0.0001 s(-1) to a final true strain of 0.2, while the microstructure characterization is performed using Electron Backscatter Diffraction and Transmission Electron Microscopy. At room temperature, the AA sample shows the highest hardness (strength), but at temperatures of 400 degrees C and 500 degrees C, the DA sample possesses the highest strength. Interestingly, the AP sample exhibits comparable strength to the DA sample at 500 degrees C, which could indicate for applications at these high temperatures, LPBF-PH13-8 Mo does not require any heat treatment.