SELECTIVE LASER MELTING OF HIGH PERFORMANCE FERROUS ALLOYS

Abstract

Selective laser melting (SLM) is presently the predominant metal additive manufacturing technology. However, the pool of alloys for which the SLM process is well understood remains small. Ferrous alloys are a technologically important class of materials but are largely untapped by SLM. To address the identified gaps in the literature, two types of ferrous alloys are investigated: high strength low alloy martensitic steels (AISI 4130, AISI 4340) as well as high magnetic saturation FeCo2V alloy. The underlying process-microstructure-property relationships between SLM and the alloys under study are investigated and clarified. Excellent strength and ductility in SLM martensitic steels arise from the in-situ quench and ultra-fast thermal cycling, which opens possibilities for the tuning of mechanical properties. The characteristic thermal history of SLM also suppresses ordering in bulk FeCo2V, enabling excellent strength and ductility in an otherwise brittle material.