A Comprehensive Study on Effects of Cryogenic Treatment on Cemented Tungsten Carbide Material

This study highlights the recent progress made in understanding the effect of subzero temperature (cryogenic) treatment on the mechanical, tribological, and microstructural characteristics of tungsten carbide materials, as reported in the recent literature. It discusses the processes by which the deep cryogenic treatment alters the microstructure, particularly the cobalt binder phase and the dispersion of the tungsten carbide grains, resulting in improvement in mechanical and tribological properties. The recent work covers techniques for characterizing changes in grain structure using microscopy and changes in mechanical properties using mechanical testing, such as wear tests, hardness, and fracture rupture strength, to implement it for industrial applications that demand high wear resistance and longer service life. The cryogenic parameters like soak time and temperature is very critical for achieving uniform dispersion of carbide phase and reduction of micro-cracking which is very important for improving the fracture toughness and fatigue strength of material. Specifically, it has been observed that cryogenic treatment can induce considerable modifications in the residual stress of WC grains and facilitate phase transitions in the bonding phase, resulting in enhanced overall properties of the material with no significant changes in grain size. Such phase modification is mainly associated with precipitation of fine secondary carbides and transformation of residual austenite to martensite in the cobalt binder, as well as reduction in internal stress states. The microstructural study of different composition of tungsten carbide (WC) is required to obtain optimum cryogenic parameters to achieve desirable mechanical properties like hardness, wear resistance, and transverse rupture strength (TRS).