Ambient and high temperature tensile behaviour of DLD-manufactured inconel 625/42C steel joint

In recent years, much attention has been directed towards multi-material systems produced using additive manufacturing technologies. Especially directed energy deposition-based systems provide a powerful tool for relatively simple production of components with controlled chemical composition in certain directions and locations. In this contribution, the potential of bimetallic material manufacturing based on the combination of nickel alloy Inconel 625 and 42C steel using direct laser deposition process was investigated. The monolithic single material blocks as well as graded blocks with alternate material deposition order were produced and investigated via light and scanning electron microscope. In addition, the miniaturized tensile tests at ambient and high temperatures were performed. It was observed that the character of two-material joint changed with the order of deposited materials. Based on the maps of chemical composition, it was shown that joint Inconel 625 to 42C was rather gradual, while 42C to Inconel 625 had sharp distribution of the main elements around the fusion line. The tensile test results demonstrated that the location of preferential failure was the joint itself in the case of gradual interface regardless of the test temperature. On the other hand, the sharp joint failed within Inconel 625 material at room temperature, while at elevated temperature the failure was observed in 42C steel region.