A viscoplastic deformation model considering material damage is used to predict hot tear formation in a permanent mold magnesium alloy casting. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. Ductile damage theory is used to find mechanically i...

Determination of critical points on hot stress-strain curve of metals is crucial in thermo-mechanical processes design. In this investigation a mathematical modeling is given to illustrate the behavior of metal during hot deformation processes such as hot rolling. The critical strain for the onset of dynamic recrystallization has been obtained as a function of strain at the maximum stress. In a...

Experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304H stainless steel. Three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the DRX critical strain: strongly strain dependent softening by SRX alone with softening kinetics control...

Mathematical models were created using the finite element method and research was carried out on options for hot, semi-hot cold crimping in a container matrix of special profile axisymmetric hollow blanks made high-carbon steel with variable wall thickness along height. A plastic model metal is used. Before hot crimping, part workpiece heated at height to be deformed. The shape dimensions initi...

To investigate the hot deformation behavior of 17-7 PH stainless steel, hot compression tests were carried out at the temperatures of 950, 1050 and 1150 oC and strain rates of 0.001 s-1 to 0.1 s-1. Accordingly, the hot working behavior was studied by the analyses of flow stress curves, work hardening rate versus stress curves, exponent- type constitutive equations and deformed microstructures. ...

Human observers easily recognize complex natural phenomena, such as flowing water, which often generate highly chaotic dynamic arrays of light on the retina. It has not been clarified how the visual system discerns the source of a fluid flow. Here we show that the magnitude of image deformation caused by light refraction is a critical factor for the visual system to determine the perceptual cat...

The effects of the post-deformation annealing on microstructural evolution hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated. multi-pass rolling was applied stir cast samples. Annealing then to at 450 °C for 4 h. Microstructural examined by SEM, EDS, EBSD techniques. data showed that addition 0.87 vol.% (GNPs + CNTs) significantly inhibited occurrence recrystal...