A review on cryogenic treatment of tungsten carbide (WC-Co) tool material

Cryogenic treatment is a thermal treatment process in which the parts are usually cooled to temperatures below -70 C (< 203 K) to induce metallurgical changes in materials. The treatment has shown a significant performance improvement in most of the ferrous materials and it's alloy, by transforming retained austenite to martensite and precipitating secondary carbides. However, the effect of such low-temperature treatment on highly stable super hard material like tungsten carbide (commonly referred to as "cemented carbide") is uncertain. But researchers have reported precipitation of eta-phase carbides, densification of cobalt binder, refinement of tungsten carbide grains, phase transformation of cobalt, and changes in residual stress in cryogenically treated tungsten carbide (WC-Co) material which resulted in increased hardness and wear resistance. Hence, this paper focuses on summarizing the cryogenic treatment parameters used in different studies, the rate of performance improvement in different applications, and reported mechanical and metallurgical changes, which would serve as a pool of knowledge for future researchers.