The paper addresses damage accumulation processes that occur during static deformation in steels 45 and 09G2S and in brass L63 in the initial state and upon 'grain annealing.' The authors discuss new experimental evidence on the damage accumulation kinetics during deformation of polycrystalline materials that differ in nature and grain size, including materials in the unloaded state and those under stresses, with small and very small strains (0.05-0.15%). The results obtained have been the necessary physically consistent explanations. Analytical approximations of the correlation between the main mechanical properties of materials (hardness, yield stress, and ultimate strength) and their structure parameters (grain size) are given. [ABSTRACT FROM AUTHOR]
Stoev, P., Starolat, M., Vasil'ev, A., Khovrich, S., and Kovtun, K.
Subjects
*ACOUSTIC emission, *HAFNIUM, *DEFORMATIONS (Mechanics), *MECHANICAL properties of metals, *FRACTURE mechanics, *ELASTOPLASTICITY, *STRAINS & stresses (Mechanics), *ANNEALING of metals
Abstract
The paper addresses the dependence of acoustic emission produced in rolled hafnium GFÉ-1 under tensile deformation on the material's structural state. A correlation has been established between the material structure, the level of mechanical properties and the values of acoustic parameters. Acoustic emission in non-recrystallized hafnium under tensile deformation is recorded only at the stages that precede fracture. Upon recrystallization annealing at temperatures of 1123 and 1373 K acoustic emission occurs at all the stages of tensile deformation. The highest level of acoustic emission activity in hafnium is observed during the transition from elastic to elastic-plastic strain. [ABSTRACT FROM AUTHOR]
We describe the application of the dual boundary element method for the determination of stress intensity factors in plate bending problems. The loadings considered include internal pressure, and also combined bending and tension. Mixed mode stress intensity factors are evaluated by a crack surface displacement extrapolation technique and the J-integral technique. The boundary element results for the case studies considered in the paper have been compared with either analytical or finite element results and in all cases good agreement has been achieved. [ABSTRACT FROM AUTHOR]
The paper considers methods of accelerated determination of endurance limits of metals and alloys based on the analysis of regularities in their inelastic deformation, strain and energy criteria of fatigue fracture, and methods for life prediction with the use of those criteria. [ABSTRACT FROM AUTHOR]