Oleksandr D. Vasylyev

• Professor
• Researcher at Frantcevych Institute for Problems of Materials Science, Kyiv, Ukraine

In static tensile tests, the temperature range of transition from shear to ductile fracture in polycrystalline molybdenum is 400–450°C. The position of the lower temperature limit T brl is found from the condition $\sigma _t (T_{br}^l ) = \sigma _{b_t } (T_{br}^l )$ . The position of the upper temperature limit T bru is close to 0.2Tmelt, at whi...

The effects of C on failure of polycrystalline Mo under uniaxial tension in the ductile-brittle transition temperature range were investigated. It was found that in a two-phase molybdenum alloy of optimal composition the structural states of the boundary zones and the matrix are qualitatively equivalent to one another: on loading the deformation is...

The effect of microadditions of hafnium and HfC carbide on the strength and plastic characteristics of molybdenum obtained by electron beam melting is considered. Low-alloyed molybdenum alloys containing 0. 15-0. 25 wt. % of HfC are more resistant to intergranular failure in their state after melting and are more resistant to high temperatures afte...

This paper is an historical essay on development of fuel cell technologies in Ukraine and short description of the National Program on Fuel Cells. It is shown that fuel cell technologies have both many years positive experience in Ukraine owing to Oganes Davtjan’s efforts since early 50th of the 20th century, which were interrupted by political eve...