Investigation of a ceramic metal matrix composite functional surface layer manufactured using gas tungsten arc welding

摘要

Wear resistant surfaces with high toughness and impact resistant properties areto be created to improve the life cycle cost of brake discs for trains. A potentialsolution to this industrial problem is to use an arc cladding process. This workdescribes the application of gas tungsten arc welding (GTAW) for a structuralceramic Metal Matrix Composite (MMC) on steel. The structure of the twoceramics examined indicates the possibility of development of a wear resistantsurface, which would extend the life of the brake disc. Silicon Carbide (SiC)and Tungsten Carbide (WC) ceramics were studied to embed them in a steelmatrix by an advanced GTAW method. WC particles penetrated the liquid weldpool and also partially dissolved in the steel matrix, whereas, SiC because ofthe physical properties never penetrated deeper into the weld pool butsegregated on the surface. Successful embedding and bonding of WC led tothe decision to exercise an in-depth analysis of the bonding between the WCparticles and the matrix. Chemical analysis of the matrix revealed more WCdissolution as compared to particle form within the clad. It was observed thatWC reinforcement particles built a strong chemical bond with the steel matrix.This was shown by electron backscatter diffraction (EBSD) analysis. The hardclad layer composed of WC reinforced steel matrix gave an matching frictioncoefficient to high-strength steel in cold wear conditions through Pin-on-Discwear and friction testing. A prototype railway brake disc was created with theestablished GTAW parameters to find out the difficulties of producing industrialscale components.