Abstract—The effect of severe plastic deformation performed in a Bridgman anvils at 77 K on the saturation magnetization, the phase composition, and the crystal geometry characteristics of the phases of a metastable austenitic–martensitic Fe–18Cr–10Ni alloy is investigated. High-pressure (hydrostatic) torsion at a true strain e = 3.4–5.8 at 77 K is found to form two martensitic phases, namely, the ferromagnetic α phase and the paramagnetic ε phase. Mechanisms explaining the nature of changing the saturation magnetization are proposed.

A study of the phase transformation in technically pure titanium under different types of deformation has been performed: upset under high pressure and high hydrostatic-pressure torsion (HPT). A set of modern methods of the study included microindentation, X-ray diffraction, transmission electron microscopy, as well as EXAFS-spectroscopy in synchrotron radiation for detailed studying a local atomic structure of phases. The correlation between the phase transformation course and the deformation method has been found. It has been shown that in contrast to pressure without a shear component, the shear deformation under high pressure at room temperature contributes to the occurrence of a high-temperature β-phase with a local atomic order different from that in the initial phase.

The effects of heat treatment with continuous laser radiation on samples of the Fe–18Cr–10Ni alloy of the austenitic-martensitic class that have undergone preliminary megaplastic torsional deformation in the Bridgman chamber are investigated. It is established that the combined application of deformation (deformation in the Bridgman chamber) and thermal (laser heating) effects to the alloy forms the structure of metastable austenite (γ phase), which differs from stable austenite in higher strength characteristics. The nature of this phenomenon is discussed.

This article reviews the main properties of explosive incendiary compounds, their effectiveness and applications. The effects of mechanical processing on the kinetic characteristics of the transformation of powder mixtures are alsodiscussed.

This study consideres application of the digital image correlation method for estimating the relative deformations of composite materials obtained with the use of thermal treatment by laser radiation. The use of this technology made it possible to determine the mechanical properties of materials containing macroscopic austenite regions distributed in the martensite matrix according to a given law. The evolution of strain fields that occur when a load is applied to the samples under study is determined. The influence of the shapes and sizes of regions with high plastic properties (austenite) on the integral mechanical characteristics of composite materials has been studied.

Исследованы механические характеристики композитных материалов на основе сплава Fe – 18 % Cr – 10 % Ni, состоящих из пластичных макроскопических областей аустенита, распределенных в высокопрочной мартенситной матрице. Получены кривые напряжение – деформация для образцов, в которых аустенитные области различаются по размерам и форме. На основе анализа построенных диаграмм определены формы аустенитных областей, оптимальные с точки зрения сочетания прочностных и пластических характеристик материала.

The mechanical properties of pressings from alloy 1960 in state T1 are determined at 20, 55, 60 and 65°C. Samples of pressings from alloy 1960 in state T1 are tested for creep resistance for up to 5000 h at 55, 60 and 65°C at a stress of 295, 390 and 440 MPa. The creep rate and the deformation of the samples are determined. It is shown that increase of the temperature to 65°C in the tensile tests lowers the strength characteristics of the pressings by 20 – 40 MPa. Increase of the temperature and of the stress in the creep tests elevates the creep rate of the pressings.

Mechanical characteristics of composite materials based on Fe – 18% Cr – 10% Ni alloy and composed of plastic macroscopic austenite regions distributed in a high-strength martensite matrix are studied. Stress-strain curves are obtained for the specimens with austenite regions differing in size and in shape. The plotted curves are used to determine the shapes of the austenite regions optimal in terms of combining the strength and ductility parameters of the material.

Определены механические свойства штамповок из сплава 1960 в состоянии Т1 при 20, 55, 60 и 65 °C. Проведены испытания на ползучесть образцов штамповок из сплава 1960 в состоянии Т1 при температурах 55, 60, 65 °C и напряжениях 295, 390, 440 МПа длительностью до 5000 ч. Определены скорость ползучести и деформация образцов. Показано, что повышение температуры до 65 °C при испытаниях на растяжение приводит к снижению прочностных характеристик штамповок на 20 – 40 МПа. Повышение температуры и напряжений при испытаниях на ползучесть вызывает увеличение скорости ползучести штамповок.

Mechanical characteristics of composite materials based on Fe – 18

The data on the effect of carbon and nitrogen on the stacking fault energy (SFE) of austenitic steels are summarized. Threshold values of SFE characterizing the stability of austenite are given. The effective value of SFE for high-nitrogen austenitic steels is found to be 20–25 mJ/m2. At this value, these steels have the best combination of strength, ductility, and impact strength at a retained high stability of austenite to the γ–ε–α transformation during cooling and plastic deformation.

The influence of severe plastic (megaplastic) deformation in a Bridgman anvils on the structure, hardness, and spontaneous magnetization of a metastable Fe–18Cr–10Ni alloy in two initial states, namely, austenitic state after hot plastic deformation and martensitic state after subsequent cold plastic deformation, is investigated. High-pressure (quasi-hydrostatic) torsion at a true strain e = 4.7–5.8 is found to form two martensitic phases, namely, the ferromagnetic α phase with a high specific saturation magnetization and the paramagnetic ε phase. Two dispersed phases, which differ significantly in magnetic respect, largely explain the complex nature of changing the saturation magnetization with the strain and the high hardness of the alloy.

Computer modeling based on thermodynamic predictions is used to show that the Ac 3 temperature can vary by tens of degrees, depending on chemical composition. Chemical heterogeneity in the bulk of continuous cast steels can therefore affect the material’s mechanical properties. Auger spectroscopy and mechanical tests of the hardened rolling of two general purpose steels (09G2S and St3) are used to establish that a layer-by-layer change in the yield strength in St3 steel is due to the heterogeneous composition of the solid solution. In 09G2S steel, it is due to the heterogeneity of the phase composition.

A study is performed of the effect intense laser heating has on the strength characteristics of the γ‑phase in iron–chromium–nickel alloys. We show that using laser radiation to heat the initial α-phase to the temperature of the α → γ transformation produces a γ-phase with much higher microhardness and yield stress than those of the equilibrium γ-phase. A possible mechanism of this phenomenon is discussed.

The metallophysical principles and technological aspects are considered for developing a new class of materials characterized by a spatial distribution of macroscopic zones with different physical and mechanical properties, as well as gradient materials. The potential for making such materials has been demonstrated by the example of alloys belonging to the iron-chromium-nickel system of the austenitic-martensitic class. The role of severe plastic deformation and heat treatment using laser radiation for the production of materials consisting of paramagnetic macroscopic zones distributed in a certain way within a ferromagnetic matrix is analyzed. The potential for using such materials for manufacturing active parts of electrical machine rotors are discussed.

The sequence of structural transformations of amorphous alloys Fe53.3Ni26.5B20.2 and Co28.2Fe38.9Cr15.4Si0.3B17.2 during heat treatment in a wide temperature range was studied by transmission electron microscopy and differential scanning calorimetry. The response of mechanical properties (plasticity, hardness, crack resistance) during transition from an amorphous to a crystalline state was investigated. The nature of discovered embrittlement phenomenon and plasticizing effect in amorphous alloys during annealing was discussed.