Using of High-Energy Methods for Production of Nanocrystallic Materials

摘要

We have determined an interrelation between physical-chemical properties of initial ultra-disperse powders (UDP) Ta_2O_3 and nano-powders Al_2O_3, produced by different methods, with a microstucture and physical-mechanical properties of experimental samples. We have investigated peculiarities of static and dynamic compaction of the abovementioned powders. It showed that using dynamic compaction enables to get compacts with density 15-20 % higher than when using conventional static one, which is dew to destruction of fragile structural elements, their reciprocal friction and high-speed heating. We have studied mechanisms of sintering the samples within the temperature range of 1300-1600 ℃ and investigated its influence on crystallites sizes, porosity and their distribution according to their sizes. Using high-energy loading methods (a static at high pressure and temperature and a dynamic one) enabled to produce a more dense (up to 98-99 %) nano-crystallite structure (100-500 nm) of the material, which has microhardness and cracking-resistance 1.2-1.4 times higher than during conventional consolidation methods.