Dynamic Strain Aging during the Plastic Flow of Metals

Wei Guo Guo

doi:10.4028/www.scientific.net/KEM.340-341.823

Paper Titles

Long Term Creep Analysis of Pipe Bends in a Steam Transfer Line at Elevated Temperature
p.795

Quantitative Description of Microscopic Plastic Deformation of Polycrystalline Aluminum Using Laser-Scanning Microscope
p.803

Modeling of Large-Strain Cyclic Plasticity for Accurate Springback Simulation
p.811

Constitutive Modeling for Uniaxial Time-Dependent Ratcheting of SS304 Stainless Steel
p.817

Dynamic Strain Aging during the Plastic Flow of Metals
p.823

Calibration of Texture-Adjusted Strain-Rate Potential and its Application
p.829

Effect of Texture on High Temperature Deformation Behaviors of Ti-6Al-4V Alloy
p.835

Plasticity as a Lifesaver in the Design of Cardiovascular Stents
p.841

Plasticity in the Mechanical Behaviour of Cardiovascular Stents during Stent Preparation (Crimping) and Placement (Expansion)
p.847

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Dynamic Strain Aging during the Plastic Flow of Metals

Abstract:

In the present paper, in order to better understand the third type “dynamic strain aging” occurring during the plastic flow of metals, the uniaxial compressive experimental data ever obtained in University of California, San Diego using an Instron servo-hydraulic testing machine and the Hopkinson technique are systematically analysed. These experimental data cover the plastic flow stress of several fcc, hcp, bcc polycrystalline materials and several alloys at a broad range of temperatures (77K – 1,100K) and strain rates (0.001/s – 10,000/s). In analysis, the appearing region of the “dynamic strain aging ” under different temperatures and strain rates are respectively plotted by the curves of stress vs temperature, and stress vs strain for fcc, hcp and bcc metals. The results show that: (1) this third type “dynamic strain aging ” occurs in all hcp, bcc and fcc polycrystalline or alloy materials, and there are different profiles of stress-strain curve; (2) the “dynamic strain aging ”occurs in a matching coincidence of the temperature and strain rate, its temperature region will shift to higher region with increasing strain rates; (3) bcc materials do not have an initial pre-straining strain as the onset of work-hardness rate change for the “dynamic strain aging ”; and (4) based on the explanations of dynamic strain aging with serration curves (Portevin-Lechatelier effect) and other explaining mechanisms of references, The mechanism of third DSA is thought as the rapid/continuous formation of the solute atmospheres at the mobile dislocation core by the pipe diffusion along vast collective forest dislocations to result in a continuous rise curve of flow stress. Finally, several conclusions are also presented.