Mechanical properties of Inconel 625 laser cladded coatings: Depth sensing indentation analysis

Ni-base superalloys, like Inconel 625, exhibit a high corrosion and oxidation resistance. For this reason, these alloys are typically used to manufacture engineering components, or coatings for cheaper metallic substrates, which should work in extreme conditions including mechanical loads and an aggressive environment at high temperature. Some of these applications could be found in chemical and petrochemical plants, power generation sector, aircraft engines components, heat exchanger tubing or boilers of waste incinerators. The advantages of using coatings protecting cheaper materials are the significant cost reductions compared to using bulk alloys.In this work, a Ni-base superalloy Inconel 625 was deposited onto a medium alloy steel by laser cladding using a high-power diode laser. A process parameters selection was performed following a Taguchi's array with the aim to reduce the number of performed tests. The mechanical properties (hardness and elastic modulus) of the Inconel 625 coatings were studied by nanoindentation. The mechanical properties were obtained from each indentation as a function of the penetration depth. These results were compared with those obtained previously in two other Inconel 625 coatings processed by cold-spray and laser re-melting cold-spray techniques. A comparison among the mechanical properties and the microstructures of these coatings was carried out to evaluate alternative methods to produce Inconel 625 coatings.