Structure and properties of WC-Co alloys in solid-phase sintering. II. Mechanical properties of samples

The mechanical properties of hard WC-Co alloys produced by solid-phase sintering at various temperatures are discussed. It is shown that the bending strength and hardness of these alloys may be the same as those achieved in liquid-phase sintering. The difference between solid-phase and liquid-phase sintering is only in the time it takes to achieve the dense state. Excellent mechanical properties at rather low temperatures (1150–1200 °C) can be obtained by sintering under pressure. High hardness can be achieved at 1000–1100 °C by hot isostatic pressing of nanoscale powders. The excellent mechanical properties of solid-phase-sintered hard WC-Co alloys indicate that strong interphase and intercarbide boundaries occur earlier than the liquid phase.     

Properties of photochromic retinals

In the present review, we summarize our recent studies on the synthesis and spectral-kinetic parameters of photochromic retinals based on spiropyrans, diarylethenes, and a fulgimide and the use of these compounds for the preparation of artificial analogs of natural bacteriorhodopsin.     

Trying out spraying modes and properties of wear-resistant flame Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–TiO<Subscript>2</Subscript> coatings fabricated using a flexible cord material

Samples of Al₂O₃–TiO₂ coatings are fabricated by the flame spraying of a flexible cord. The influence of process parameters and composition of the sprayed material on the structure, composition, and mechanical properties of coatings is investigated. It is shown that an increase in the spraying distance and feed rate of the sprayed material leads to a decrease in their density. An increase in the concentration of the low-melting TiO₂ component predetermines a decrease in the coating porosity and has no significant effect on the coating hardness. Being subjected to measuring scratching, Al₂O₃–TiO₂ flame coatings formed with minimal porosity (Π = 3.2%) are characterized by cohesion fracture behavior and no substrate opening under an indenter load of up to 90 N. The friction factor of coatings under study varies from 0.2 to 0.78 after 2800 counterbody revolutions (44 m of the friction path). This is associated with the accumulation of fatigue cracks in the coating material and its subsequent cohesive fracture by the formation of large fragments serving as an abrasive.     

The hydrogen atom allowing for gravity

The hydrogen atom is comprised of a proton and an electron possessing charges and masses. The latter involves a gravitational interaction. Since hydrogen atoms are the most abundant in the Universe, their gravitational radiation proves to be of importance for cosmology.     

Processability and Structure Formation of the Al–Zn–Mg–Ca–Fe–Zr–Sc Alloy upon Hot Rolling and TIG Welding

Russian Journal of Non-Ferrous Metals - Technological regimes for producing wrought products (2 and 1 mm) from the Al–4.5%Zn–2.5%Mg–2.5%Ca–0.5%Fe–0.2%Zr–0.1%Sc...