Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

Morphology of the cephalothorax integument of Bryocamptus pygmaeus (Copepoda: Harpacticoida: Canthocamptidae), based on a new research method

The number and location of sensilla and pores of the cephalothorax integument of the species Bryocamptus pygmaeus (G.O. Sars, 1863) (Copepoda, Canthocamptidae) were studied for the first time on the material from several European regions: the southeastern part of the Bolshezemelskaya tundra (Nenets Autonomous District), the north of the Komi Republic, the Republic of Karelia, and the central part of European Russia (Udmurt Republic). In the samples examined, two groups of populations differing in the characters of cephalothorax integument were recognised. These differences were found to correlate with the variability of the endopod of fourth pair of female legs, which bears four setae in specimens of the eastern form, while a specimen examined from Karelia has five setae. Pore maps are composed for both groups of morphotypes. A statistical analysis was carried out based on a new technique using three-dimensional models of the cephalothorax. As a result of this analysis, a high similarity between individuals of the eastern form and differences of the latter from the Karelian specimen were revealed