Microscale effect of high-temperature exposition on laser cladded Inconel 625-Cr3C2 metal matrix composite

Abstract

Metal matrix composites are advanced materials designed to improve the performances of metals by the addition of a ceramic phase. Laser cladding technique was considered in this work to deposit Inconel 625-Cr3C2 composite coating onto ferritic and stainless steel substrates. The effect of exposition at high temperature, at 520 and 800 °C, on the microstructure and the mechanical properties of the matrix of Inconel 625-Cr3C2 composite clads was studied. The coatings' microstructure evolution, as a function of high-temperature exposure, was analysed by scanning and transmission electron microscopy. Depth sensing indentation tests were performed on the surface of the clads to obtain the evolution of the elastic modulus and the hardness with the exposition time. Finally, microstructure and mechanical properties were correlated, analysing the measurements done in the matrix and in the ceramic particles. The results were compared with those obtained for Inconel 625 clads in a previous study. While the exposition at 520 °C did not affect the matrix of the composite coating, at 800 °C it was observed a formation of hardening phases. In all the cases, the mechanical properties of the composite matrix resulted improved with respect to the Inconel 625.