Effect of the kinematics of rotary rolling on the fineness of the structure of hypereutectoid silumins

It has been established experimentally that the internal layers of cylindrical semifinished products that are made of hypereutectoid silumins and contain embedded lengthwise pins do not intermix during rotary rolling. The experiment also determined that the angles through which different concentric internal layers of the semifinished product (ω₁ > ω₂ > ω₃) are twisted are different and depend on the radii of those layers (R′₁ > R′₂ > R′₃). This finding contradicts the hypothesis of rigid sections in the classical theory of the strength of materials. An analytic relation (empirical formula) is found to describe the pitch of the internal layers of metal flow in relation to the main parameters of the rotary-rolling operation (the feed angle α and deformation ε) and the radius of the given internal layer (R′_x). Another empirical formula is proposed to determine the angle of inclination of the helical lines along which the metal inside the rolled specimen is displaced. A mathematical model is constructed to describe the dependence of the ductility properties of hypereutectoid silumin alloys on changes in the dimensions of the silicon crystals in the alloys when semifinished products made of these alloys are deformed by rotary rolling. __________ Translated from Metallurg, No. 8, pp. 68–72, August, 2006.     

Mathematical model of the movement of layers of metal during the rotary rolling of semifinished products made of hypereutectic silumins

A mathematical model has been constructed to describe the kinematics of the movement of metal on the surface of semifinished products made of hypereutectic silumin alloys as they undergo rotary rolling. The model is based on the dependence of the pitch of the helical lines of metal flow on the deformation ε of the product and the feed angle α. The pitch is minimal when ε = 50–55%, regardless of the feed angle α. The degree of deformation ε = 50–55% is optimum for ensuring that the unit number of cycles in which the semifinished product is loaded by the work rolls is such as to produce a fine-grained structure and maximize the ductility characteristics of hypereutectic silumins. __________ Translated from Metallurg, No. 6, pp. 57–59, June, 2006.     

Processes of Charge State Change at Collisions of He2+ and ArZ+ Ions with Fullerenes

Using coincidence technique the relative cross-sections of charge state change and fragmentation at one and two electron capture processes have been measured for the first time at collisions of He²⁺ and Ar^z+ projectiles with fullerenes in the energy range (3-35)z keV.     

Study of the growth of YBa2Cu3O7−x films on a Al2O3 single crystal with a CeO2 buffer sublayer

Superconducting YBa₂Cu₃O_7−x films were prepared by magnetron sputtering on Al₂O₃ single crystals with a CeO₂ sublayer. Scattering of moderate-energy ions and x-ray diffraction were used to show that the films exhibit good single-crystal properties over the entire thickness up to 2.6 μm. The hypothesis is advanced that the indentations formed by the growth of films above “extraneous” phase grains may act as defect sinks. Pis’ma Zh. Tekh. Fiz. 24, 91–95 (January 12, 1998)     

certain trends in the development of technology and improvement in quality of nuclear fuel (review)

The trends in the improvement of the economic characteristics of nuclear power plants, one of which is the prolongation of the reactor campaign, i.e., the period in which the fuel is situated in the active zone under the due increase in its burnup level, are considered. Such an increase can be achieved, specifically, via using fuel with burnable absorbers, as well as by improving the quality of fuel pellets obtained by powder metallurgy. It is necessary to toughen the technical requirements for fuel pellets and improve the technology of their production and the equipment used in their fabrication. It is noted that the works for improving the operational factors of fuel pellets (particularly, lowering their gas release and decreasing the interaction of the fuel with the cladding) are currently mainly oriented to producing pellets with burning absorbers; obtaining the optimal microstructure (porosity and grain size) of the pellets; improving their shape; excluding dust on their surface after smoothing; and stabilizing their properties in regards to geometric sizes, density, and aftersintering.     

Hollow corundum spheres for high temperature thermal insulation

Conclusions We developed a technological route for the production of hollow electrocorundum spheres intended for manufacturing highly refractory thermal insulation products, concrete bodies, and loose charges. The technology was tested under industrial conditions.Translated from Ogneupory, No. 7, pp. 27–30, July, 1987.     

Modular concepts of quality assurance in chemical reactor engineering

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 3, pp. 34–36, March, 1992.