Accession Number : AD0611836

Title :   SURFACE VACANCY PITS AND VACANCY DIFFUSION IN ALUMINUM,

Corporate Author : BROWN UNIV PROVIDENCE R I METALS RESEARCH LAB

Personal Author(s) : Basu,B. K. ; Elbaum,C.

Report Date : DEC 1964

Pagination or Media Count : 20

Abstract : The width of regions depleted of vacancy pits, near various grain boundaries, were measured in aluminum for several temperatures of pit formation. These measurements, combined with the measured temperaturetime relation during pit formation, allow one to evaluate the activation energy, E sub m, for vacancy diffusion. In the present study it was found that E sub m=17+1 Kcal/mole for aluminum. Boundaries with disorientation angles ranging from 2 degrees to 50 degrees were found to be equally effective sinks for vacancies, which indicates that this property is not sensitive to the details of boundary structure. A comparison of the pit density with the dislocation density shows that these pits do not necessarily nucleate at the intersections of dislocations with the surface. (Author)

Descriptors :   (*SURFACE PROPERTIES, ALUMINUM), (*ALUMINUM, DIFFUSION), (*CRYSTAL DEFECTS, ALUMINUM), HEAT OF ACTIVATION, GRAIN BOUNDARIES, NUCLEATION, DENSITY

Distribution Statement : APPROVED FOR PUBLIC RELEASE