Research on the behavior of hot re-pressing of TiB₂Cu-Ni composite produced by combustion synthesis

TiB₂-40Cu-8Ni ceramic-metal composite with the relative density of about 90% was prepared by combustion synthesis. In order to improve the mechanical properties, firstly the elastic-plastic deformation behavior of TiB₂-40Cu-8Ni cermet in high temperature compression was studied. Secondly the hot re-pressing was conducted under different temperatures at 1200°C, 1250°C and 1300°C respectively. The deformation behavior, microstructure and mechanical properties changes were investigated in detail. The results showed that the relative density and the flexural strength increased greatly after hot re-pressing. The flexural strength reached 608 MPa and the relative density reached 96% at 1300°C, and increased by 12% and 5% respectively. The analysis of SEM indicated that the morphology of TiB₂ particle transformed from equiaxial shape into rod-like shape. The evolution of TiB₂ morphology and growth mechanism was analyzed according to TiB₂ crystal structure characteristics.