Accession Number : AD0704656

Title :   STRESS RELAXATIONS AT INTERFACES IN INDIUM AND INDIUM-THALLIUM ALLOYS,

Corporate Author : DEFENCE STANDARDS LABS MARIBYRNONG (AUSTRALIA)

Personal Author(s) : DE Morton,M. E.

Report Date : 02 JUN 1969

Pagination or Media Count : 10

Abstract : Low-frequency internal friction and shear modulus measurements were made on pure indium and indium-rich thallium alloys in the FCT and FCC phases. Polycrystalline indium does not exhibit grain-boundary relaxations, due to the extreme ease of slip within the grains. A damping peak and shear modulus relaxation was, however, observed in single crystal and polycrystalline indium at -100C; these effects are believed to be associated with the nucleation and subsequent stress-induced propagation of fine deformation twins in FCT indium. It is suggested from shear modulus data and published expansion data that a higher order phase transition occurs in indium at -100C. Relaxations were observed in polycrystalline indium-thallium alloys at 50C (0.75 Tm) in both the FCT and FCC forms, and these were associated with the motion of grain boundaries. The relaxation strengths measured for grain boundary damping in the FCT alloys were larger by a factor of three over those measured for the FCC alloys. (Author)

Descriptors :   (*INDIUM, STRESSES), (*INDIUM ALLOYS, STRESSES), THALLIUM ALLOYS, INTERFACES, INTERNAL FRICTION, STRAIN(MECHANICS), GRAIN BOUNDARIES, AUSTRALIA

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE