Dry sliding wear behaviour of additive manufactured CrC-rich WC-Co cemented carbides

Recent progress in additive manufacturing (AM) enables the development of novel cemented carbides for specifically wear-related applications. However, the available literature on their tribological performance is very limited. The present work aims to reveal the friction and wear performance of AM-produced cemented carbides consisting of a cobalt (Co) matrix and -65 vol % of tungsten (W) and chromium (Cr) -rich carbides through dry reciprocating wear tests under different conditions (counterbodies: alumina and hardened AISI 52100 steel balls; loads 10 N and 30 N), in-situ scratch wear testing, post-test microscopy, and laser profilometry. The dominant wear mechanism was abrasion against alumina and adhesion against steel through the removal of the Co matrix, along with surface oxidation and tribolayer formation. The coefficient of friction increased by 11.9% with increasing load against steel, whereas it remained the same against alumina, indicating a bearing effect due to the oxidation of the wear track. The specific wear rate increased by 7.3% against alumina with increasing load, while it sharply decreased by 56.4% against steel, presumably due to surface strain-hardening. The in-situ scratch wear testing under a scanning electron microscope revealed degradation of the Co matrix and carbides network over time. These observations provided evidence of tribolayer formation and strain-hardening of the Co matrix. The present paper contributes to understanding the tribological behaviour of AM-produced CrC-rich WC-Co cemented carbides, which are promising for innovative and longer-lasting mining and machine tools.