Hardmetals with nanograin reinforced binder: Binder fine structure and hardness

Ultra-coarse grained WC–Co hardmetals with nanograin reinforced binder and the trade name Master Grades were recently developed and implemented in industry on a large scale. The results on the binder fine structure of the binder of the Master Grade obtained by TEM and HRTEM indicate the presence of nanoparticles of several nanometers in size embedded in a matrix of fcc Co. The micro-hardness of the binder of conventional hardmetals with various carbon contents is found to vary from HV 0.05 = 360 to HV 0.05 = 470, whereas that of the nanograin reinforced binder is equal to HV 0.05 = 780. The nanohardness of the binder of a conventional ultra-coarse grade and the Master Grade is found to be roughly 7.5 GPa and 10.2 GPa and their Young’s modulus is equal to 390 GPa and 410 GPa correspondingly.