Accession Number : AD0477766

Title :   AN INVESTIGATION OF INTERDIFFUSION IN METALLIC SINGLE CRYSTALS.

Descriptive Note : Final rept. 1 Nov 62-31 Aug 65,

Corporate Author : OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Personal Author(s) : Powell ,G. W. ; Hirth,J. P.

Report Date : DEC 1965

Pagination or Media Count : 57

Abstract : With the objective of studying defect interaction in the diffusion zone of binary couples, three independent investigations were carried on this project. They are: (1) determination of the equilibrium vacancy concentrations in gold-silver alloys; (2) study of marker movement in gold-silver alloys; and (3) transmission electron microscopy study of thin foils prepared from the diffusion zone of gold-silver diffusion couples. Copper-platinum alloys also were to be investigated, but experimental difficulties did not permit the work to get beyond study of the gold-silver alloys. The most important conclusions of the investigation of equilibrium vacancy concentrations in gold-silver alloys are: (1) the vacancy concentrations of quenched pure gold determined with the dilatometer at room temperature are in good agreement with the values obtained by investigators using other methods. (2) The high energy of vacancy formation in the alloys is caused by specimen contraction, resulting from the migration of divacancies, which occurred before the measurements with the dilatometer could begin. (3) The small black spots which are observed in thin foils of quenched gold appear to be very small stacking-fault tetrahedra. (4) A reappearance of delta L/L contraction was noted at 600 C for the alloys but not for pure gold and this was found to correspond to a much greater density of vacancy precipitates observed in the alloys. (Author)

Descriptors :   (*SINGLE CRYSTALS, DIFFUSION), (*CRYSTAL DEFECTS, ALLOYS), GOLD ALLOYS, SILVER ALLOYS, COPPER ALLOYS, PLATINUM ALLOYS, ELECTRON MICROSCOPY, ANNEALING, FILMS, DILATOMETERS, QUENCHING, FOILS(MATERIALS)

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE