Co-Mo-Cr-Si coating on Haynes 282 by a novel hybrid method of laser direct deposition and selective remelting

This presentation covers a novel hybrid method of the crack-free fusion of CoMoCrSi, which is a cobalt-based alloy with molybdenum additions with the composition analogous to Tribaloy® T400, on Haynes 282 for parts where extreme wear is problematic with high temperatures and corrosive media, such as industrial turbine applications, commercial jet engines, and rocket engines. To alleviate cracking of the coating during laser surface deposition/coating, previous attempts relied on preheating of the substrate to reduce cracks to alleviate a thermal mismatch between the substrate and molten powder. The primary aim of this work is accomplished by fusing crack free CoMoCrSi layer using a novel hybrid process of combining laser cladding and laser remelting processes. The optimal process conditions of coating crack-free CoMoCrSi coating on Haynes 282 were determined for both the laser powderbed fusion and remelting processes and the microhardness and chemical compositions of the coating layers produced using optimal process parameters with and without remelting the substrate were compared. The chemical compositions of different phases present in the coating layer were analyzed by Energy Dispersive X-ray Spectroscopy (EDS). Unlike the preheating method used in the past, the remelting process yielded minimal to no dilution at the surface, resulting in the preservation of the original CoMoCrSi coating properties. This research shows that the remelting process is a promising method for scaling up to industrial applications.