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.

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.

Mechanical characteristics of composite materials based on Fe – 18

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.

We have measured the temperature dependence of the resistivity and magnetization of a special steel of the Fe–Cr–Ni austenite–martensite class in a wide temperature range (77–1100 K). It is found that at temperatures 77–170 K, the resistivity of the material almost remains unchanged, but upon a further increase in temperature, the resistivity sharply increases, which is probably a result of disordering. In addition, anomalous behavior of resistivity with vanishing spontaneous magnetization is observed at 910 K, which is associated with the ferromagnet–paramagnet phase transition. Comparison of the measured ρ( T ) dependence with the analogous dependence for 12Kh18N10T austenite stainless steel has not revealed features typical of Fe–Cr–Ni steel.

AbstractWe have measured the temperature dependence of the resistivity and magnetization of a special steel of the Fe–Cr–Ni austenite–martensite class in a wide temperature range (77–1100 K). It is found that at temperatures 77–170 K, the resistivity of the material almost remains unchanged, but upon a further increase in temperature, the resistivity sharply increases, which is probably a result of disordering. In addition, anomalous behavior of resistivity with vanishing spontaneous magnetization is observed at 910 K, which is associated with the ferromagnet–paramagnet phase transition. Comparison of the measured ρ( T ) dependence with the analogous dependence for 12Kh18N10T austenite stainless steel has not revealed features typical of Fe–Cr–Ni steel.

Plates with a doubly periodic commensurate lattice of circular holes are studied. The plates are cut from a corrosion-resistant steel sheet along and across the rolling direction. Uniaxial tensile tests are performed, and the effective elastic modulus is determined for longitudinal and transverse plates with various lattice orientations with respect to the longitudinal axis of a plate. The experimental and calculated results agree well.

Ferromagnetic austenite–martensite steels are laser-irradiated to obtain spatially nonuniform distribution of magnetization. An original setup that employs the Faraday effect in epitaxial ferrite-garnet films is used to visualize and measure the spatial distribution of magnetization in steels that are processed with the aid of a fiber laser at different scanning rates. It is demonstrated that rapid laser heating of samples causes modification of the microstructure from the martensite state to the austenite state that provides paramagnetic properties.

The effect of cyclic laser heating on the formation of the austenite structure in the austenitic-martensitic alloys based on Fe-Cr-Ni system is investigated. It is shown that under the influence of ultra-fast laser heating on the martensite, which was formed during plastic deformation, the reverse martensitic transformation occurs, and austenite with high strength characteristics is formed. Repeated and multiple laser heating effectively grinds areas of austenite to a size close to the large nanoparticles. There is an additional increase in the strength characteristics of austenite as a result of this fragmentation.

The possibility of the use of laser radiation heating for making materials with specified distribution of ferro-and paramagnetic domains is studied. It is shown that application of plastic deformation with a high degree or reduction combined with subsequent laser heating in a specified temperature range to austenite-martensite alloys based on the Fe – Cr – Ni system produces materials with required distribution of regions of ferromagnetic martensite and paramagnetic austenite. The modes of laser treatment providing maximum strength of the formed austenite are determined.

Экспериментально исследованы особенности лазерной наплавки порошков на основе никеля с добавками нанопорошка TaC. В процессе экспериментов были определены минимальная глубина проплавления основы, распределение микротвердости по сечению подложки, насыщение металла наплавки компонентами основы.