In-situ neutron diffraction study of wrought and selective laser melted maraging stainless steels

Bulk phase transformations and dislocation density were monitored in a maraging stainless steel on bulk level using in-situ neutron diffraction up to 1340 °C, i.e. 30 °C below the melting temperature. Three materials with different initial microstructure and/or composition studied: wrought, as-built SLM-ed (selective laser melted) re-austenitized SLM-ed. In contrast wrought martensitic steel, was essentially ferritic. However, recovered usual microstructure. A ?-ferritic domain above 1200 confirmed for all studied. amount of ?-ferrite at point strongly depends upon composition. Additionally, it shown that (ferritic or martensitic) has little no influence re-austenization. Dislocation densities estimated from peak broadening. The ferritic SLM material contains high (~4 × 1014 m?2), which is however far less than (~5 1015 m?2). Dislocations start annihilate 550 / 600 studied, but measurable ~1013 m?2 still observed 950 1000 °C.