Laser cladding as a flexible exploration tool for the design of cobalt-free hardfacing coatings made of high entropy materials

Clément Vary (1, 2) , Pascal Aubry (1) , Ivan Guillot (2) , Peter Grünc (3) , Jörg Kasparc (3) , Maria Barbosa (3)

1 SEARS - Service d'études analytiques et de réactivité des surfaces
2 ICMPE - Institut de Chimie et des Matériaux Paris-Est
3 Fraunhofer IWS - Fraunhofer Institute Material and Beam Technology [Dresden]

Significant research efforts have been undertaken over the past forty years to replace the Stellite® cobalt-based alloys, which boast outstanding performances when used as hardfacing coatings, but proved problematic especially in radioactive environments. This works purpose is to contribute to this effort by coming up with viable substitutes made of Complex Concentrated Alloys (CCAs). Previous work evidenced the (CrFeNi)90Mo5Ti5 alloy as a promising base that relies on the formation of intermetallic phases within a ductile matrix for an increase in hardness and an improved tribological behaviour. In this particular framework, the DLDs in situ alloying capabilities were used for further explorations around the (CrFeNi)$_{90}$Mo$_5$Ti$_5$ composition. Coupled with an extensive use of the CALPHAD method, this combinatorial strategy dramatically speeds up material development compared to what the more conventional ways can achieve. Comparisons between the as-built and the CALPHAD-predicted microstructures mostly highlighted inaccuracies, imputable to a lack of reliability in the databases for this particular system, but a comparative approach still allowed to assess the impact of variations imposed on the Cr, Fe and Ni contents. The present paper mostly emphasizes on the methodology and the tools that were developed within this study, as such elements are growing in importance in the current context of intensive global research for new materials.

Domaines: Matériaux

Clément Vary, Pascal Aubry, Ivan Guillot, Peter Grünc, Jörg Kasparc, et al.. Laser cladding as a flexible exploration tool for the design of cobalt-free hardfacing coatings made of high entropy materials. Procedia CIRP, 2022, Conference on Photonics Technologies, 111, pp.201 - 204. ⟨10.1016/j.procir.2022.08.047⟩. ⟨cea-03965402⟩