Stability of zirconium oxides in Nb-Mo-ZrO2 alloy

The paper gives the results of investigations on the rate of coalescence of zirconium oxides in Nb-Mo-ZrO₂ alloy. On the basis of experimental results and theoretical estimates, it is shown that the stability of zirconium oxides in a niobium matrix increases substantially when the oxygen content in the solid solution rises. A high stability of zirconium oxides in niobium, which ensures a considerable (up to T 1800°C) increase in the recrystallization temperature and enhancement of the mechanical properties of the alloys at T 1100°C can be attained at an oxygen content C₀ 0.2–0.5 at.% in the solid solution.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 76–79, May, 1982.     

Relation between the synthesis conditions and the fine structure of fiber carbon

The fine structure of carbon fibers synthesized under various technological conditions is studied. It is found that the material of the fibers is heterogeneous and its component composition is determined by thermomechanical treatment conditions and the presence of a boron addition and depends on the angle of coherent-domain orientation φ with respect to the fiber axis. The detected dependences of the component composition of the fibers on the heat-treatment temperature and time and the angle of coherent-domain orientation with respect to the fiber axis suggest that the transition of the carbon material of the fibers into a more equilibrium state is likely to proceed through a number of metastable states.     

Thermal stability of the microstructure of 12% chromium ferritic–martensitic steels after long-term aging at high temperatures

The structure of EK-181 (RUSFER-EK-181, low-activation) and ChS-139 12% Cr ferritic–martensitic steels is investigated and their mechanical properties are tested after long-term (13500 h) aging at 450 and 620°C. The microstructure of the steels exhibits a high thermal stability, which provides the retention of their initial short-term mechanical properties at test temperatures.     

On the Algebra of Symmetry of the Dirac Equation in Flat Space and De Sitter Space

The structure of the quadratic algebras of spinor symmetry operators for the Dirac equation is studied in a four-dimensional flat space and in the de Sitter space of arbitrary signature. The algebras are shown to be standard equivalent. Linear noncommutative subalgebras meeting the conditions of the noncommutative integrability theorem are found in these algebras.     

A Study of Common Factors of Plastic Deformation Via a Flow of Point Defects in the Fields of High Local Pressure Gradients in Metallic Materials

Russian Physics Journal - In the frame of a quasi-viscous mechanism of plastic deformation via the flows of nonequilibrium point defects in the fields of local pressure gradients, peculiarities of...