NON-ELASTIC UNLOADING OF COPPER AND ALUMINUM
Abstract
The mechanical hysteresis curves of copper and aluminum single crystals and polycrystalline samples were measured at 25 and -196 degrees C in the plastic strain range of 0.0001. A departure from elastic unloading is ascribed to the motion of piled-up glide dislocations toward their sources. The stress at which reverse plastic flow starts on unloading is associated with the force required for the glide dislocations to cut (over) through a forest of intersecting dislocations with the formation of a jog. The jog formation energy is calculated to be 1.0 e.v. at 25 C and 1.4 e.v. at -196 C for copper and 0.2 e.v. at 25 C and 0.4 e.v. at -196 C for aluminum. The temperature dependence of the jog formation energy is ascribed to the constriction of stacking faults on the intersection of the partial dislocations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1960
- Accession Number
- AD0248450
Entities
People
- A.r. Rosenfield
- B.l. Averbach
Organizations
- Massachusetts Institute of Technology