Onset Mechanism of Strain-Rate-Induced Flow Stress Upturn

Onset mechanism of strain-rate-induced flow stress upturn.

The strain-rate response of flow stress in a plastically deforming crystal is formulated through a stress-sensitive dislocation mobility model that can be evaluated by atomistic simulation. For the flow stress of a model crystal of bcc Fe containing a 1/2[111] screw dislocation, this approach describes naturally a non-Arrhenius upturn at high strain rate, an experimentally established transitio...

PREDICTION OF CRITICAL STRESS AND STRAIN FOR THE ONSET OF DYNAMIC RECRYSTALLIZATION IN PLAIN CARBON STEELS

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...

Temperature and strain-rate dependence of the flow stress of tantalum single crystals in cyclic deformation

Effect of Changing Strain Rate on Flow Stress during Hot Deformation of Type 316L Stainless Steel

In industrial rolling, changes in strain rate and temperature occur with strain during passes, and between one pass and the next. Plane strain compression testing has been used with ramped changes in strain rate during deformation, and with changes in strain rate between two deformations to study their effects on flow stress. No systematic deviations from a mechanical equation of state were fou...

Virtual melting as a new mechanism of stress relaxation under high strain rate loading.

Generation and motion of dislocations and twinning are the main mechanisms of plastic deformation. A new mechanism of plastic deformation and stress relaxation at high strain rates (10(9)-10(12) s(-1)) is proposed, under which virtual melting occurs at temperatures much below the melting temperature. Virtual melting is predicted using a developed, advanced thermodynamic approach and confirmed b...