Exothermic synthesis and consolidation of single-phase ultra-high temperature composite Ta4ZrC5

The paper presents the experimental results of possibility obtaining ultra-high temperature composite Ta4ZrC5 using a single-stage method. The method is based on the use of exothermic synthesis of refractory compounds by electro-thermal explosion (ETE) and their consolidation under conditions of quasi-isostatic compression. The effect of mechanical activation of the reaction mixture of tantalum, zirconium and carbon powders on the formation of the phase composition of the ceramic composite Ta4ZrC5 was studied. The conditions for obtaining a single-phase ultra-high temperature composites had were determined. The composites were prepared with the average particle size of 1-2 µm and a residual porosity of 8-10%.

The Fragmentation of Al-W Granular Composites Under Explosive Loading

ABSTRACTSmall scale explosively driven fragmentation experiments have been performed on Aluminum (Al)-Tungsten (W) granular composite rings processed using cold isostatic compression of Al and W powders with a particle size of 4-30 microns. Fragments collected from the experiments had a maximum size of the order of a few hundred micrometers. This is a dramatic reduction in the fragment size when compared to the 1-10 mm typical for a homogeneous material such as solid aluminum under similar loading conditions. Numerical simulations of the experiment were performed to elucidate the mechanisms of fragmentation that were responsible for this shift in fragmentation size scales. Simulations were performed with a significantly stronger explosive driver to examine how the mechanisms of fragmentation change when the detonation pressure increases.