Abstract Nonlinear constitutive equations are proposed to model variations in flow stress as a function of strain rate and temperature during hot deformation. Modified applied seventy data sets about deformation alloys. Two modifications conventional models introduced, viz. (1) nonlinear (2) multivariate with the fitting simultaneously two variables. The predictive accuracy was evaluated using ...

Fine grain polycrystals of MgO have been prepared from a Mg(OH)2 powder by reactive hot-pressing at 900°C. The densification rate is discussed in terms of superplastic deformation. The bend strength and the effective surface energy for fracture initiation y. have been determined as a function of porosity between room temperature and112000~. A rapid increase in yi with temperature is observed ab...

The deformation behavior and microstructure of 25CrMo4 axle steel was systematically investigated by thermal compression deformation. hot-compression test a sample carried out on Gleeble-3800 mechanical simulation tester. flow the alloy studied at temperature (900–1200 °C), strain rates (0.01; 0.1; 1.0) s–1 maximum 60 %. curves under different conditions were obtained, effects rate appearance a...

The plastic behavior of crystalline materials is mainly controlled by the nucleation and motion of lattice dislocations. We report in situ dynamic transmission electron microscope observations of nanocrystalline nickel films with an average grain size of about 10 nanometers, which show that grain boundary-mediated processes have become a prominent deformation mode. Additionally, trapped lattice...