Sintering Behavior of WC-Co with Additives of TiC, VC, and (Ta, Nb)C: Microstructural and Mechanical Features

In the present study, WC-10Co with TiC, VC and (Ta, Nb)C as the inhibitors to the grain growth was prepared using high energy ball milling and the subsequent HIP process at various temperatures. Phase evolution and microstructural studies were performed for the milled and sintered samples by x-ray diffraction, vibrating sample magnetometry, field emission scanning electron microscopy and transmission electron microscopy. Also, the density and microhardness of the sintered samples were measured. It was found that densification and grain-growth rate were sensitive to the sintering temperature, type and overall content of the additives. The samples sintered at the higher temperature showed better densification and hardness, with lower porosities. The additives were found to have significant influence on the microstructure and properties of the sintered products. Sintered samples containing additives had considerably improved microhardness, but densification was lowered up to 4.8%. However, the highest microhardness was 1920 HV for the sample with the three types of additives sintered at 1480 °C.