Improvement of surface microhardness and wear resistance of WC/Co hard alloy by high current pulsed electron beam irradiation

• The HCPEB irradiation was performed on a WC/Co hard alloy of mark YG6X.
• A covering layer composed of nano-grained WC1 − x and Co3W9C4 phases was formed.
• The surface microhardness was increased to 2430 HK.
• The wear rate reduced to one eighth of the initial state.
• Overused HCPEB irradiation led to severe surface cracks.

High current pulsed electron beam (HCPEB) irradiation was conducted on a WC/Co hard alloy. The modified surface microstructure was characterized with methods of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The surface microhardness and wear resistance were measured. Under HCPEB irradiations, the surface layer was melted and the refined WC particles dissolved with Co bonding material. A covering layer composed of a mixture of nano-grained WC1 − x and Co3W9C4 phases was formed on the modified surface with a thickness of ~ 1 μm. After 20 pulses of HCPEB irradiation, the surface microhardness of YG6X hard alloy was increased to 2430 HK and the wear rate reduced drastically to one eighth of the initial state.