New Developments in Understanding Harper–Dorn, Five-Power Law Creep and Power-Law Breakdown
Abstract
:1. Introduction
- (1)
- Temperatures near the melting point with a slope of 1 (stress exponent of 1), (HD).
- (2)
- Temperatures above approximately 0.6Tm where the constant slopes for crystalline materials vary from 3.5–7 (5-PL).
- (3)
- Below about 0.6Tm, the stress exponent is no longer constant and power-law breakdown is observed (PLB) This is sometime referred to as intermediate temperature creep that extends to roughly 0.3Tm.
2. General Creep Plasticity Considerations and Five Power-Law Creep
3. The So-Called Harper–Dorn Regime
- Activation energy about equal to lattice self-diffusion,
- Grain-size independence with grain boundary shearing,
- Steady-state stress exponent of one,
- Dislocation density that appears independent of stress, and
- A primary creep stage.
4. Power law Breakdown
5. Conclusions
Funding
Acknowledgments
Conflicts of Interest
References
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Kassner, M.E. New Developments in Understanding Harper–Dorn, Five-Power Law Creep and Power-Law Breakdown. Metals 2020, 10, 1284. https://doi.org/10.3390/met10101284
Kassner ME. New Developments in Understanding Harper–Dorn, Five-Power Law Creep and Power-Law Breakdown. Metals. 2020; 10(10):1284. https://doi.org/10.3390/met10101284
Chicago/Turabian StyleKassner, Michael E. 2020. "New Developments in Understanding Harper–Dorn, Five-Power Law Creep and Power-Law Breakdown" Metals 10, no. 10: 1284. https://doi.org/10.3390/met10101284