Effects of deep cryogenic treatment on microstructure and properties of WC-11Co cemented carbides with various carbon contents

The effects of deep cryogenic treatment on the microstructure and properties of WC-11Co cemented carbides with various carbon contents were investigated. The results show that after deep cryogenic treatment, WC grains are refined into triangular prism with sound edges via the process of spheroidization, but WC grain size has no evident change compared with that of untreated alloys. The phase transformation of Co phase from α-Co (FCC) to ɛ-Co (HCP) is observed in the cryogenically treated alloys, which is attributed to the decrease of W solubility in the binder (Co). Deep cryogenic treatment enhances the hardness and bending strength of the alloys, while it has no significant effects on the density and cobalt magnetic performance.