Precipitation Under Cyclic Strain in Solution-Treated Al-4wt%Cu II: Precipitation Behavior
Abstract
Solution-treated Al-4wt%Cu was strain-cycled at ambient temperature and above, and the precipitation behavior investigated by Transmission Electron Microscopy (TEM). In the temperature range 100 degrees C to 200 degrees C, precipitation of theta-prime-prime appears to have been suppressed, and precipitation of theta-prime promoted. Anomalously rapid growth of precipitates appears to have been facilitated by a vacancy super-saturation generated by cyclic strain, with a diminishing effect observed at higher temperatures due to the recovery of non-equilibrium vacancy concentrations. The theta-prime precipitates generated under cyclic strain are considerably smaller and more finely dispersed than those typically produced via quench-aging due to their heterogeneous nucleation on dislocations, and possess a low aspect ratio and rounded edges of the broad faces due to the introduction of ledges into the growing precipitates by dislocation cutting. Frequency effects indicate that dislocation motion, rather than extremely small precipitate size, is responsible for the reduction in aspect ratio.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2009
- Accession Number
- ADA535528
Entities
People
- Adam Farrow
- Campbell Laird
Organizations
- Los Alamos National Laboratory