E. G. Chernyshev

Structural and phase transformations in ferromanganese alloys during deformation under pressure

Using optical metallographic, TEM, Mössbauer spectroscopy, and X-ray analysis the structural and phase transformations in Fe-(3–55) wt % Mn alloys during shear deformation under pressure were investigated. It is established that a large deformation under high pressure causes the formation of a nanocrystalline structure with grain sizes of 40–60 nm. Nanostructure increases the hysteresis of inverse (hcp-fcc) transformation and stabilizes the (hcp) ɛ phase in alloys containing more than 40 wt % Mn, up to normal conditions. The Fe-3 wt % Mn alloy after shear under pressure treatment became nanostructured, retaining the original bcc phase state.

Formation and properties of copper-silver solid solutions upon severe deformation under pressure

Nonequilibrium nanocrystalline FCC solid solutions are obtained via the mechanical alloying of Cu1.0 − x-Agx powders (x = 0.1, 0.2, …, 0.9, 1.0) with deformation under pressure and their properties are investigated. The chemical homogeneity, microstructure, mechanical properties, and thermal stability of the alloys are investigated. The alloys have the positive deviation of lattice parameters from the Vegard law with crystallite sizes of 20 nm, hardness exceeding the initial values of the components by 4.5–6 times, and a brittle character of fracture. The thermally induced decomposition of nonequilibrium solutions starts at temperatures close to room and is complete after heating to 500°C with the development of collective recrystallization.

Structural State of Ni-Mn Solid Solutions in a Wide Range of Concentrations Based on the Data of Scattering and Absorption of X-Rays

It has been demonstrated that Ni-Mn alloys prepared from elemental powders by the method of mechanical alloying appear to be fcc solid solutions in a wide concentration range. Structural studies of samples with the amount of Ni from 50 to 95 at % were carried out by the methods of X-ray diffraction, electron microscopy, and EXAFS spectroscopy.

Nanocrystalline Ni-Mn solid solutions: New materials with competing exchange interaction

Structural investigations of nanocrystalline Ni-Mn solid solutions in a wide range of concentrations have been performed by electron microscopy, x-ray scattering, and EXAFS spectroscopy.