We study experimentally the dynamical heterogeneities occurring at slow shear, in a model amorphous glassy material, i.e., a 3D granular packing. The deformation field is resolved spatially by using a diffusive wave spectroscopy technique. The heterogeneities show up as localized regions of strong deformations spanning a mesoscopic size of about 10 grains and called the "hot spots." The spatial...

In engineering materials, microstructural evolution during hot-working critically determines the properties of the finished part. Intermetallic TiAl alloys are no exception and numerous attempts have been made to improve their performance by subjecting them to harmonized hot-working steps. In the current work a novel in-situ diffraction technique along with conventional microscopic methods were...

Hot deformation behavior of the Cu-Cr-Zr-Nd alloy was studied by hot compressive tests in the temperature range of 650-950 °C and the strain rate range of 0.001-10 s(-1) using Gleeble-1500D thermo-mechanical simulator. The results showed that the flow stress is strongly dependent on the deformation temperature and the strain rate. With the increase of temperature or the decrease of strain rate,...

The microstructure and texture evolution of Ti-5Al-5Mo-5V-1Cr-Fe alloy during hot compression were investigated by the electron backscatter diffraction technique. The results reveal that two main texture components containing <100> and <111> fiber textures form after the hot compression. The fraction of each component is mainly controlled by deformation and strain rate. Dynamic strain-induced b...

A three-phase model is presented that predicts solid deformation and damage as well as melt pressure, feeding flow and shrinkage porosity during metal casting. A visco-plastic constitutive theory with damage is used to model the solid deformation. Damage created by mechanically induced voiding is used as a hot tear indicator. The absence of liquid feeding determines when damage starts to form. ...

The evolution of texture as a function of recrystallization has been characterized for hot-rolled AA1050. Samples prepared from a hot rolled sheet were annealed isothermally for sufficient time to allow complete recrystallization. The spatial orientation variation within the deformed microstructure of nucleation, growth and orientations of recrystallized grains is examined. The microstructural ...

The aim of the present study is the prediction of critical conditions (including critical strain and flow stress) for the initiation of dynamic recrystallization during thermo-mechanical processing of plain carbon steels. For this propose, torsion tests were conducted at different temperature (1050, 1100 and 1150˚C) and strain rates (0.002, 0.02 and 0.2/s). All flow curves showed a peak st...