Plastic deformation throughout strain-induced phase transformation in additively manufactured maraging steels

A comprehensive study was intended to show the microstructural features of additively manufactured (AM) 18Ni-300 maraging steel. Uniaxial tensile tests were conducted on specimens built using laser powder bed fusion (LPBF) technique for two different layer thicknesses. The have lowest possible porosity, and showed stages strain hardening. In stage I, dislocation density increased, leading a positive hardening rate. negative rate due necking effect then followed in II. X-ray diffraction (XRD) analyses revealed phase transformation through deformation. Various via electron backscattered (EBSD) with large scans over three zones representing undeformed, deformed, severely deformed close fracture area. pole figures orientation distribution functions (ODF) texture evolving deformation process agreement kernel average misorientation (KAM) grain boundary maps. Transmission microscopy (TEM) used detect inclusions segregated alloying elements adjacent fractured surfaces. Results indicated that led diminishing austenite (?) phase, while transformed sourced high area at cell boundaries.