Nadezhda Dudova

Short-range ordering and the abnormal mechanical properties of a Ni-20% Cr alloy

Effect of temperature on mechanical properties of a Ni-20% Cr alloy with an initial grain size of 100 µm in the temperature interval 150–1000°C (0.25–0.8 Tm) has been studied. It is shown that in the temperature range 400–600°C the alloy demonstrates a positive temperature dependence of both the flow stress and the coefficient of strain hardening and exhibits Portevin-le Chatelier effect (PLC). It has been established on the basis of a comparison of data of calorimetric studies and temperature dependence of mechanical properties that the unusual mechanical behavior of Ni-20% Cr alloy is a result of the occurrence of short-range order. The nature of the effect of the short-range order on the mechanical properties is discussed.

Deformation mechanisms in Cr20Ni80 alloy at elevated temperatures

AbstractThe mechanisms of plastic deformation of Cr20Ni80 nichrome with an initial grain size of 80 μm were studied in the temperature range 600–950°C and the strain-rate range 1.5 × 10−6−5 × 10−2s−1. Nichrome is shown to exhibit anomalously high values of stress exponent n and a high deformation activation energy Q. These unusual properties were found to be caused by “threshold” stresses below which deformation does not occur. An analysis of the deformation behavior with allowance for threshold stresses reveals the regions of hot, warm, and cold deformation in nichrome. At normalized strain rates

Dynamic Recrystallization Mechanisms Operating under Different Processing Conditions

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Microstructural Evolution in a 9%Cr-3%Co-3%W-VNb Steel during Creep

kT/D1Gb < 10−8, the true values of n and Q are ∼4 and 285 ± 30 kJ/mol, respectively. In the normalized-strain range 10−8−10−4n ∼ 6 and the deformation activation energy decreases to 175 ± 30 kJ/mol. This change in the deformation-behavior characteristics is explained by the transition from high-temperature dislocation climb, which is controlled by lattice self-diffusion, to low-temperature dislocation climb, which is controlled by pipe diffusion, as the temperature decreases. At

Dynamic strain aging behavior of 10Cr steel under low cycle fatigue at 650°C

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Microstructure Evolution during LCF of a 10%Cr Steel at Room Temperature

kT/D1Gb = 10−4, a power law break-down takes place and an exponential law (which describes the deformation behavior in the range of cold deformation) becomes operative.