Influence of the antiphase domain structure on the long-range atomic order parameter in the Ni3Mn alloy with superstructure L12

The antiphase domain structure in the Ni₃Mn alloy with superstructure L1₂ with various manganese contents has been studied. It has been found that a deviation of the alloy composition from the stoichiometry leads to the formation of manganese oxides at the antiphase domain boundaries and grain boundaries. With an increase in the antiphase domain sizes, the domain size distribution function changes from the normal to lognormal, and the degree of long-range atomic order decreases.     

Change in the phase composition and defect structure of a multicomponent ordered Ni-based alloy upon high-temperature annealing

Phase transformations upon the high-temperature annealing of a multicomponent Ni-based alloy produced via direct crystallization are studied by diffraction electron microscopy. The alloy is annealed at T = 1000°C for a prolonged period. The phase composition is determined. The dislocation structure and behavior of the γ-phase during prolonged annealing are studied.     

Deformation hardening and temperature dependence of mechanical properties in ternary ordered alloys based on Ni3Fe I

The variation of hardening factor and resistance to deformation with the quenching and testing temperatures for ordered alloys based on Ni₃Fe was investigated. It was shown that the yield point _0.2 and flow stresses are independent of the quenching temperature right up to about 450 ° C. At higher quenching temperatures there are increases in _0.2 and in the flow stresses corresponding to small degrees of deformation ( < 10%); the highest mechanical properties are found when the quenching temperature is near the Curie point. In quenching from a temperature above the Curie point the mechanical properties and hardening factor fall suddenly to values corresponding to the disordered state of the alloys. The temperature variation of _0.2 is similar to that mentioned above. The deformation stress at high values and the hardening factor decrease with increase in testing temperature, and below the Curie point they reach values corresponding to the disordered state. The temperature variation of mechanical properties for specimens in which the formation of long-range order is suppressed by special treatment is characterized by the absence of substantial change near the Curie point. The results obtained are discussed in relation to modern dislocation theories of hardening of alloys with long-range order.     

Geometrically necessary dislocations in FCC polycrystalline metallic materials on the mesoscale

The dislocation structure of deformed copper alloys doped with Mn and Al was determined by selected area diffraction (SAD), performed using a transmission electron microscope. The scalar dislocation density, the density of geometrically necessary dislocations, and the density of statistically stored dislocations were measured. Special attention was given to the size of grains. The effect of size on the accumulation of geometrically necessary dislocations was studied.     

Use of physical methods and electron microscopy in analyzing structural changes in Ni3Fe alloy

Results of studies of structural and mechanical properties ofNi ₃ Fe alloy are presented. The densities and types of dislocations in the alloy, the parameters of dislocation interaction, and the energy expended in deformation ofNi ₃ Fe specimens in various initial states are estimated. The strain hardening behavior of orderedNi ₃ Fe alloy is shown to be influenced by a number of external factors, such as deformation or γ-irradiation. Tomsk State Architectural University, Tomsk 634003. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 3, pp. 211–215, May–June, 1999.     

Phase Transformations and Misorientations in Ferrite-Martensitic Steel upon Intense Plastic Deformation

Changes in the structural and phase state of low-carbon steel with a mixed structure of tempered martensite and ferrite, and deformed by equal channel angular pressing (ECAP), are analyzed by means of transmission electronic microscopy and X-ray diffraction. The impact ECAP has on the phase composition and morphology of the alloy is determined. The behavior of the carbide phase is studied. Grain misorientations are measured. Special attention is given to the problem of fine grain formation upon ECAP.     

Structure and Phase Composition of Heat-Affected Zone of Austenite Steel After Deformation

Russian Physics Journal - The paper presents the transmission electron microscopy (TEM) investigations of the thin film structure and phase composition of the heat-affected zone (HAZ) of a weld...     

Antisite defects in the Ni3Al phase

Different types of antisite defects are considered, reasons for their occurrence are classified in detail, their relationship with the ordering energy is traced, and some estimates of the ordering energy are made on the basis of the melting temperature.     

Influence of tempering on the dislocation substructure and scalar density for cast construction intermediate-alloyed steel

The method of diffraction electron microscopy is used to study the influence of the tempering period on the defect structure of the Fe-0.38C-3.5Ni-1.3Cr-0.24Si-0.35Mn-0.4Mo-0.15V-0.3Cu cast construction steel. It is demonstrated that tempering causes the substructural nonfragmented → fragmented substructure transformation, which is the main substructural transformation. Three types of fragments are formed, including initial and anisotropic secondary fragments with network and cellular dislocation substructures and tertiary isotropic dislocation-free fragments. The fragmentation process at tempering is accompanied by a continuous decrease in the scalar dislocation density. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 44–50, January, 2006.