Accession Number : ADA191548

Title :   Superplasticity - A Fundamental Investigation on Deformation Mechanism and Cavitation Phenomena.

Descriptive Note : Annual technical rept. 1 Feb 87-31 Jan 88,

Corporate Author : CALIFORNIA UNIV DAVIS DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Chokshi, A H ; Bieler, T ; Mukherjee, A K

PDF Url : ADA191548

Report Date : 15 Feb 1988

Pagination or Media Count : 32

Abstract : Al-Li alloy and the mechanically alloyed IN 91211 were investigated for superplasticity and enhanced plasticity. The deformation behavior of fine and coarse grains (coexisting in the same microstructure) was a function of strain rate. Both type of grains deformed in an intercrystalline manner in region II. In region III, only the fine grains deformed in this mode. The mechanically alloyed specimens revealed the high ductility of 500% elongation at the uncommonly high strain rate of 10 per sec. The stress exponent of strain rate for this alloy does not correlate with existing models for superplasticity. Additional mechanical and microstructural work underway are expected to shed more light on the micromechanism of deformation for this alloy. Keywords: Superplasticity, Aluminum Lithium alloys; Mechanically alloyed systems; Whisker reinforced matrix; Deformation mechanism; Silicon carbide whiskers.

Descriptors :   *ALUMINUM ALLOYS, *LITHIUM ALLOYS, *GRAIN STRUCTURES(METALLURGY), CAVITATION, DEFORMATION, DUCTILITY, HIGH RATE, MECHANICAL WORKING, MICROSTRUCTURE, PLASTIC PROPERTIES, SILICON CARBIDES, STRAIN RATE, STRESSES, WHISKERS(CRYSTALS), FIBER REINFORCED COMPOSITES, GRAIN SIZE, ALUMINUM ALLOYS, BEHAVIOR, CAVITATION, DEFORMATION, DUCTILITY, HIGH RATE, LITHIUM ALLOYS, MECHANICAL WORKING, MICROSTRUCTURE, PLASTIC PROPERTIES, SILICON CARBIDES, STRAIN RATE, STRESSES, WHISKERS(CRYSTALS)

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE