A.M. Mazurenko's scientific contributions

The kinetics of the sintering of titanium diboride at pressures of 2.5 and 4 GPa and temperatures up to 2000°C are studied. The activation energy of the different sintering stages are determined, and the TiB2 mass transfer mechanisms characteristic of these stages are considered. The activation energy for the self-diffusion of titanium is 201 kJ/mole. Accordingly, in the second titanium diboride sintering stage at a pressure of 4 GPa plastic flow in combination with diffusion at vacancies in the metallic sublattice is obviously the predominant mechanism.

The authors assess the properties of brittleness, microhardness, porosity, microstructure, crystal structure, ductility, and grain size of the diborides of titanium, zirconium, hafnium, niobium, and tantalum under the effects of pressure. Results show that the micromechanical properties of the diborides are determined not only by the magnitude of the rms displacements of the structural elements in the crystal lattices but also by their microstructure and that the formation of fine-grained structure of diborides during their sintering under high pressure is crucial to their enhanced ductility.

The effect of the conditions of thermobaric treatment on the fine crystalline structure parameters of niobium and tantalum diboride along various crystallographic directions is studied. It is shown that for the left bracket 001 right bracket direction the dimensions of the coherent scattering region and the mean square microdeformations are greater than for the left bracket 100 right bracket direction. A correlation is established between the change in fine crystalline structure parameters and the microhardness of the sintered specimens.

The effect of grinding titanium diboride powder in air, in ethanol, and under vacuum on its sinterability at high pressures and on its microhardness is studied. It is established that grinding of the powder under vacuum activates the sintering process in sintering this powder at high pressure and ensures that fine grained specimens of high density and microhardness can be obtained.

It is shown that a transition zone is formed at the contact interface between boron nitride and metals actively interacting with them (Ti, Ta). In the case of contact between fused alloys and metals reacting weakly with boron nitride (Fe, Ni, Cr) they impregnate the CBN layer, so that its physicomechanical and cutting powers are decreased. In using refractory compounds as bases (TiC, W//2B//5, ZrN) which are solids under the synthesis conditions used, the contact interface of the layers consists of alternating sections of deep penetration of material into another, which ensures that their compounds have high mechanical strength on sintering.