New observations on the mechanisms of dynamic strian aging and of jerky flow
The rate sensitivity of the flow stress was investigated as a function of pre-strain for a commercial nickel alloy (INCONEL 600) and for polycrystalline A1-1% Mg, over a wide temperature range encompassing the regime of jerky flow. Anomalies were observed which suggest that the dynamic strain aging mechanism operates over a wider temperature range than that in which jerky flow is found. A detailed analysis shows that a negative rate sensitivity is associated with the strain hardening contribution to the flow stress from the beginning of deformation. The total rate sensitivity becomes negative only after this strain hardening contribution dominates. This suggests an interpretation of the critical strain for the appearance of jerky flow, which does not rely on the production of vacancies and moreover casts doubt on any interpretation that associates dynamic strain aging with the interaction of mobile solutes with the moving dislocations. Instead, a dislocation arrest model is used in which solute atoms diffuse along dislocations at forest intersections.
- Research Organization:
- Argonne National Lab., IL
- OSTI ID:
- 5409000
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 27; ISSN AMETA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
AGING
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
CHROMIUM ALLOYS
DEFORMATION
FLOW STRESS
FLUID FLOW
HARDENING
INCONEL 600
INCONEL ALLOYS
IRON ALLOYS
MAGNESIUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
SENSITIVITY
STRAIN AGING
STRAIN HARDENING
STRAIN RATE
STRESSES
TEMPERATURE DEPENDENCE