Preparation of WC-WB-W2B composites from B4C-W-WC powders and their mechanical properties

Abstract

Sintered composites of WC-WB-W2B were prepared from B4C-W-WC powders using a reactive energization hot-pressing technique that initiated a solid state reaction between B4C and W. Below a WC mole fraction of 0.769 in the starting powder, WB and WC were formed according to the reaction B4C + 5W + xWC = WB + (1 + x)WC, while WB, W2B, and WC were produced above a mole fraction of 0.854. Densely sintered bodies were not obtained for pure WC. Composites of WC-WB-W2B obtained at WC mole fractions between 0.854 and 0.956 were fully consolidated, having high Young's modulus and Vickers hardness values, and a fracture toughness which were comparable to those of WC.