Accession Number : AD0616068

Title :   CHANGES IN STACKING FAULT ENERGY BY ANNEALING IN COPPER-BASE ALLOYS,

Corporate Author : RUTGERS - THE STATE UNIV NEW BRUNSWICK N J COLL OF ENGINEERING

Personal Author(s) : Nakajima,K. ; Slade,J. J. ; Weissmann,S.

Report Date : 14 SEP 1964

Pagination or Media Count : 17

Abstract : The low-temperature annealing of quenched copperaluminum and copper-germanium alloys with low stackingfault energy, gamma was studied by a novel combination method. This method consists of transmission electron microscopy supplemented by the x-ray divergent beam technique. With the aid of the latter method, a complete quantitative stress-strain analysis was carried out for every annealing stage. It could be shown that short lowtemperature annealing resulted in an increase of gamma. This increase was accompanied by: (a) a recombination of partial dislocations into perfect dislocations; (b) a decrease in stored elastic energy; and (c) a directional alignment of single and dipole dislocations. Prolonged annealing led to cluster formation of solute atoms to the sites of perfect dislocations. This cluster formation was accompanied by: (a) a rise in stored elastic energy; (b) a transformation from a directional strain configuration to one more nearly spherical. The solute concentration of the clusters at the dislocation sites was estimated. The observed increase of gamma upon low-temperature annealing appears to be linked to the tendency of solute atoms to form at dislocation sites domains of short-range order. (Author)

Descriptors :   (*COPPER ALLOYS, CRYSTAL DEFECTS), HEAT TREATMENT, ENERGY, ALUMINUM ALLOYS, GERMANIUM ALLOYS, STRESSES, STRAIN(MECHANICS), ELECTRON MICROSCOPY, X RAY DIFFRACTION

Distribution Statement : APPROVED FOR PUBLIC RELEASE