CONSOLIDATION OF COMBUSTION-SYNTHESIZED TITANIUM DIBORIDE-BASED MATERIALS

The quasi-static consolidation in uniaxial compression of combustion-s ynthesized TiB2-based materials was investigated. Consolidation was ca rried out in insulated containers upon completion of the combustion re action, while the porous reaction products were ductile. Since the con solidation is not an isothermal process, the temperature change during consolidation was monitored and recorded. The effect of the addition of metallic elements to the elemental powders was established, and it was found that nickel and chromium provide the best compact integrity. The partial densification is sufficient to show significant differenc es between the effects of metallic additives. A phenomenological (not based on the micromechanisms of densification) constitutive model was applied to the hot and porous reaction products incorporating the temp erature dependence of how stress. The activation energy for the temper ature dependence of the how stress is established and indicates that, in addition to diffusion-induced plastic deformation, other processes occur, such as fracturing of ligaments.