Structure and Certain Properties of Hot-Pressed Boron Carbide-Based Ceramic with Calcium-Silicon Additive

The influence which the composition of powder mixtures, the treatment conditions which the mixtures are subjected to, and the conditions under which the hot-pressed composite materials B₄C – (5-10 mass%) calcium-silicon are fabricated exert on the structure, nature of failure, and mechanical properties of these materials is investigated. Optimum properties are possessed by material containing 10 mass% of addition. It is shown that the structure, morphology, and dispersivity, as well as the nature of the distribution of the components that are added to the composite material (secondary phase) vary as the temperature of hot pressing changes. Maximal mechanical characteristics of the composite material (σ_bend = 560 MPa, K _1c = 4.7 MPa·m^1/2, HV = 37 GPa) are attained at hot-pressing temperatures in the range 2000-2100°C.     

Self-reinforced materials based on aluminum nitride

Powder Metallurgy and Metal Ceramics -     

Existence of the Solution to the Cauchy Problem for Nonlinear Stochastic Partial Differential-Difference Equations of Neutral Type

Cybernetics and Systems Analysis - The authors consider the existence of the solution to the Cauchy problem in the class of nonlinear stochastic partial differential-difference equations of neutral...     

Structure and Properties of B4C - SiC Composites

We have investigated how the composition, grain morphology, and method of preparing the starting mixture affect the processes that form the structure and phase composition of B₄C - SiC composites during hot pressing. We found that, depending on the composition of the initial powder mixtures, which is responsible for different mechanisms of consolidation of ceramic materials during hot pressing, the grain size of the main B₄C phase and its defect content as well as the nature of the SiC phase distribution within the material differ significantly. When B₄C - SiC composites with a low SiC content are made from initial B₄C - B₄Si - B - C powder mixtures those composites have a high cracking resistance because of their fine grain structure.__________Translated from Poroshkovaya Metallurgiya, Nos. 3–4(442), pp. 112–119, March–April, 2005.     

Nondestructive testing of the thermal resistance of Gann diodes during their manufacture

The results of an investigation of the thermal resistance of Gunn diodes at different process technology cycles of their manufacturing are considered.     

Wear resistance of coatings manufactured by electric spark plating with Al-Sn electrodes

The effect of the anomalously high wear of the quenched steel counterbody was found during the testing of coatings manufactured by electric spark plating (ESP) with an AlSn alloy (20 wt % Sn). The presence of SnO₂ nanofibers in the coating composition, which are formed during the ESP with an electrode tool made of this alloy, is assumed to be the main reason for the above effect.     

Nonlinear oscillations in three-layered plates restrained along the profile

Free and forced nonlinear oscillations in three-layered rectangular asymmetric plates that are rigidly restrained along the profile are considered. These plates simulate the panels of some vehicles. The solution to the set of Grigolyuk-Chulkov nonlinear differential equations in a mixed form with respect to resolving functions of shears and stresses is constructed using the Bubnov method. The effect of rigid and geometrical parameters on amplitude-frequency characteristics of three-layered plates is investigated.