Effect of TiC content on the mechanical and corrosion properties of Inconel 718 alloy fabricated by a high-throughput dual-feed laser metal deposition system

In this work, Inconel 718 alloys with different TiC contents were fabricated one time successfully by a joint powder-fed laser metal deposition (LMD) system with two independent powder delivery systems. The TiC particles, with an average size of 20 mu m, distributed in the LMD matrix uniformly, and the Laves phase segregation in the LMD Inconel 718 alloys declined with increasing TiC content, which was attributed to the strong affinity between the Nb and C atoms. The Vicker hardness increased while the grain size decreased with increasing TiC content for the LMD Inconel 718 alloys. The nanohardness for the TiC particles was approximately 1.5 times greater than that of the gamma matrix, thus reducing the actual contact area and consequently minimizing the frictional force during sliding compared to the matrix. The corrosion rate increased slightly with increasing TiC content in the LMD Inconel 718 alloys, and micro-pits existed mainly at the bottom of the TiC particles, which was attributed to the galvanic effect induced by TiC particles and the massive discontinuity of the passive film. (C) 2019 Elsevier B.V. All rights reserved.