Influence of defects on strength and hardness of submicron WC-8Co-1Cr3C2 hard alloy

Based on the research of actual submicron WC-Co hard alloy structure, a simple model of this structure was offered. Cracking of the structure occurs in two stages: cracking of WC-WC and cracking of Co interlayer. Stress distribution in the model structure was calculated with 2D Finite Element Method (FEM). This sample with fracture criteria of the elements allows describing the influence of defects on submicron WC-Co hard alloy strength. Submicron WC-8%Co-1%Cr3C2 hard alloy with pores, η-phase (Co3W3C) and free carbon was made by conventional sintering with control of the atmosphere during sintering. Influence of defects on strength and hardness was researched both in actual samples and in the experimental sample. The minimization of defects volume in this hard alloy sample has allowed obtaining a high transverse rupture strength (1.641±0.108 GPa) and hardness (90.5±0.1 HRA).