Study of precipitation phenomena in aluminum alloys by positron annihilation

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6067670

Wampler, W R; Gauster, W B

To assess the sensitivity of positron annihilation (PA) to precipitation phenomena, the Doppler broadened PA lineshape was monitored as a function of isochronal annealing steps on a series of quenched aluminum alloys. A study of the Al--Cu system, including both PA and transmission electron microscopy, provided new information on the role of vacancies in the formation of Guinier--Preston zones and led to the conclusion that incoherent precipitate-matrix interfaces can provide efficient trapping sites for positrons. Further PA measurements on AlMg/sub 2/Si samples showed that the lineshape parameter changes coincided with microstructural changes during annealing deduced from other techniques and indicated that PA provides a sensitive monitor of these phenomena.

• Research Organization: Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 6067670
• Report Number(s): SAND-79-0727C; CONF-790437-3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360102 -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
ANNEALING
ANNIHILATION
BASIC INTERACTIONS
CHANNELING
COPPER ALLOYS
ELECTROMAGNETIC INTERACTIONS
ELECTRON MICROSCOPY
HEAT TREATMENTS
INTERACTIONS
MAGNESIUM ALLOYS
MICROSCOPY
POSITRON CHANNELING
PRECIPITATION
SEPARATION PROCESSES
SILICON ADDITIONS
SILICON ALLOYS
TRANSMISSION ELECTRON MICROSCOPY