A trade-off between powder layer thickness and mechanical properties in additively manufactured maraging steels

Abstract

In this paper, a comprehensive study on the microstructure and mechanical properties of an additively manufactured 18Ni-300 maraging steel (with the brand name MS1), fabricated through the laser-powder bed fusion (LPBF) technique is presented. The influence of powder layer thickness and the characteristics of feedstock powder as the input in the LPBF process is investigated on the microstructure and mechanical properties of solid cubes and cylindrical rods. Relative density and hardness are measured through the depth of the manufactured cubes. The study of porosity and hardness through the depth of LPBF-MS1 cubes proves homogeneous properties in the core of the material in comparison with more heterogeneous properties closer to the subsurface layers. X-ray diffraction techniques both on the powder and the as-built samples are then performed to identify phases in the fabricated samples. A correlation between lower austenite content and higher strength is observed for the tensile samples manufactured with lower powder layer thickness. Texture analysis shows a directional grain growth along the building direction resulting in a weak texture, while the material induces a stronger texture with an increased amount of austenite after the deformation. Studying the effects of powder layer thickness shows slightly lower strength and ductility for the samples manufactured with higher powder layer thickness, while the energy consumption, as well as the manufacturing time, are reduced.

Publication Title

Materials Science and Engineering A

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