Calculation of Dynamic Loading of Carbides with Various Stoichiometric Compositions
The results of numerical experiments on modeling of shock wave loading of solid and porous carbides with various stochiometric composition are presented. The model is based on the assumption that all the components of the mixture, including gas, when the shock wave loading have similar pressure, velocity and temperature. To describe the behaviour of condensed phases used equations of State of Mi-Grüneisen. Complementing the system of dynamic equations for solvability the equality condition of temperature component of mixtures you can build dependencies that can be interpreted as Hugoniot adiabat of mixture. The coefficient of the Grüneisen depends explicitly only temperature
This model has allowed to describe with precision experiment behavior of porous materials and mixes in a wide range of porosity and pressures. On the basis of these results, it was proposed to describe this model the behavior of complex materials such as carbides, considering the chemical compound as mixture. Interest in research on carbides compressibility is related, in particular, to problems of explosive compaction of powders of carbides, i.e. with the mikro piece of these compounds with properties (hardness, fragility) of initial grains of specimens. Porous carbide was viewed as porous mixture with the components of the relevant elements of the Carbide. Correlation of volumetric fraction of the condensed component was determined, as well as for solid samples by stoichiometric ratio, but the value decreased proportionally to the porosity of the sample.
Assumption about the possibility of determining the volume of components based on stoichiometric ratio, has allowed not only to describe accurately the behavior of carbides with equal shares of the components such as WC, TiC, TaC, NbC, but also the behavior of boron carbide B4C. This material has a high hardness value, yielding to this indicator only diamond that causes the increased interest The availability of experimental data made it possible to compare the calculated and experimental data, taking into account the assumptions used in the model. For volumetric proportion of boron carbide was determined by a ratio of 4: 1 respectively, chemical composition.
Thus, it is shown that the model allows you to describe dynamic loading of carbides of various porosities as a mixture of components of chemical composition of carbides. Earned fair description for carbides with equal shares of the 1:1 stoichiometric ratio and boron carbide has, accordingly, the ratio of 1:4.
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