Abstract:
The article explores an evolution of a microstructure in AISI 420martensitic stainless steel during selective laser
melting. Several upper layers had hardness of 750 HV and contained 21±12 vol.% austenite phase. The final bulk
microstructure consisted of thermally decomposed martensitewith hardness of 500–550HV and unusually high,
57±8 vol.%,amount of austenite. Obtained results indicate that duringmanufacturing a partitioning and austenite
reversion took place, owing to the thermal cycling of the inner regions duringmanufacturing. Numerical simulation
was found plausible to analyze and explain thermally activated processes that occurred in situ. Results of
numerical simulation of the thermal cycles in dependence on the processing parameters suggested a possibility
to control the thermal processes by variation of the laser energy input.
