Improved Properties of TiC Coating Deposited on Copper Alloy via Friction Stir Processing

Abstract

In this work, TiC coating on a copper alloy electrode, which is prepared by a special electron-spark deposition process (ESD), was modified by friction stir processing (FSP). The microstructure evolution of the coating was investigated, while the mechanical properties of the coating and interface were measured. The results show that FSP eliminates the cracks within TiC coating and improves the interface bonding between the TiC coating and substrate. The hardness of the FSPed TiC coating is increased about 800 HV by decreasing cracks. The elimination of the cracks within the coating is ascribed to the thermal-mechanical effect on the coating during the FSP. The increase in hardness is attributed to the decreasing number of cracks and the disappearance of columnar Cu grains, which are modified by FSP.

Critical Assessment 25: Friction stir processing, potential and problems

“…A wide variety of other particles has been examined as reinforcing phases in FSP-fabricated composites, including Fe-based metallic glass particles which retain their amorphous structure [50], and NiTi particles which can impart some shape memory behaviour to the composite [51], and low-cost glass fibres [52]. Matrix materials other than aluminium have also been explored, including copper [53][54][55], polymer [56][57][58], magnesium [59,60], and steel [61]. These techniques may hold promise; however, tool wear is a major problem when making ceramic-reinforced composites, and this is greatly exacerbated when a high temperature material like steel is used as the matrix material during FSP, with tool wear that is even more severe than when conducting friction stir welding of steels (when no ceramic reinforcement is added).…”