Accession Number : AD0682536

Title :   THE NATURE OF SLIP IN ALUMINUM CRYSTALS CONTAINING HARD PARTICLES.

Descriptive Note : Technical rept.,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS

Personal Author(s) : Russell,K. ; Ashby,M. F.

Report Date : DEC 1968

Pagination or Media Count : 40

Abstract : The report discusses certain two phase alloys remarkable for being plastically nonhomogeneous: one component of the microstructure deforms freely but the other deforms by a smaller amount, or not at all. Laue patterns, measurements of shape change, measurements of asterism by a diffractometer technique, and electron microscopy give information about the nature of slip in such alloys. These techniques were used to study crystals of Al - 3% Cu, aged to give plates which are sufficiently strong to show effects expected of a plastically non-homogeneous alloy; similar measurements were made on identical, but unaged, crystals. The results show that the two phase crystal deformed predominantly by single slip, but that extremely large gradients of shear were present in it, leading to lattice rotation and thus asterism. The rotations vary over a wavelength equal to the particle spacing, so a large lattice curvature develops, and a large density of dislocations must be stored in the crystal to accommodate the curvature. (Author)

Descriptors :   (*ALUMINUM ALLOYS, MECHANICAL PROPERTIES), DISPERSION HARDENING, DISLOCATIONS, PLASTIC PROPERTIES, X RAY DIFFRACTION, PHASE STUDIES, COMPUTER PROGRAMS, SHEAR STRESSES, STRAIN(MECHANICS), YIELD POINT, CRYSTAL LATTICES

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE