Stress-dependent recovery of point defects in deformed aluminum: An acoustic-damping study
The stress dependence of point-defect diffusion to dislocations in a 99.99% polycrystalline aluminum was studied using shear-wave attenuation and phase velocity. By holding the stress after deformation, attenuation and velocity approach their nonstressed values. The holding stress was varied between 0 and 12 MPa, after applying a 15 MPa compressive stress. Time-independent attenuation and stress-induced velocity change were introduced into the Granato-Hikata-Luecke theory, which first established the change of attenuation and velocity caused by the point-defect diffusion to dislocations. Good agreement was found between measurements and the modified theory. The stress dependence of the recovery rate was interpreted as a reduction of the migration energy of point defects diffusing to dislocations, and the activation volume was calculated for uniaxial stress. Electromagnetic acoustic resonance (EMAR) was used for the measurements. Being noncontact and highly sensitive, EMAR permitted detailed measurement of the attenuation and velocity evolutions during the unloading-holding stress sequence.
- Research Organization:
- Osaka Univ. (JP)
- OSTI ID:
- 20002018
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 14 Vol. 47; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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