The effects of TiC grain size and steel binder content on the reciprocating wear behaviour of TiC-316L stainless steel cermets

• TiC-316L stainless steel cermets have been prepared by melt-infiltration.
• Fine-grained cermets show lower wear rates than coarse-TiC equivalents.
• The cermets show a transition from two- to three-body abrasive wear.
• Adhesive wear is also observed, with a high O content tribolayer formed.
• Focused ion beam microscopy reveals sub-surface damage mechanisms.

TiC-based cermets are heavily utilised in applications demanding good resistance to both wear and corrosion. In the current work, TiC-stainless steel (grade 316L) cermets have been developed, with the TiC grain size varied through heat-treatment, for steel binder contents between 10 and 30 vol%. Microstructural analysis showed mean TiC grain sizes of ~4 and 10 μm, respectively, for fine- and coarse-grained cermets, with the grain size nominally consistent as a function of binder content. Sliding wear resistance was assessed in a reciprocating motion, using a WC–Co counter face sphere paired against the TiC cermets. Overall, the fine-grained cermets exhibit better wear resistance and hardness. The specific wear rate was seen to increase with applied load and/or binder content, for both fine- and coarse-grained materials. SEM and FIB microscopy were used to assess the microstructural changes occurring during wear. A two- to three-body abrasive wear transition was apparent, together with the formation of a surface tribolayer, which highlights a further evolution to an adhesive wear mechanism. The tribolayer showed incorporation of a high concentration of O, which increased with the applied load, together with a predominance of the binder constituents.