Accession Number : ADA293177

Title :   Localization in Tungsten Heavy Alloys Subjected to Shearing Deformations Under Superimposed High Pressures.

Descriptive Note : Final rept. Sep 91-Nov 94,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD

Personal Author(s) : Ramesh, K. T.

PDF Url : ADA293177

Report Date : 27 FEB 1995

Pagination or Media Count : 20

Abstract : This report presents the results of investigations into the deformation and failure of tungsten-based composites (tungsten heavy alloys) at very high strain rates. Several new experimental techniques developed during the course of the work include pressure-shear recovery, allowing the recovery of samples subjected to high-rate shearing deformations; the dynamic measurement of radial strains, and the continuous measurement of projectile velocities. The experimental results showed that the development of adiabatic shear localization in tungsten heavy alloys is influenced by a superimposed hydrostatic pressure. Experimental characterizations have been performed of the very high-rate response of tungsten composites with tungsten-nickel-iron and hafnium matrices. It has been shown that these materials must be treated as dual-phase composites. The addition of a hard particulate reinforcement is shown to result in a substantial increase in matrix rate-sensitivity in a model metal-matrix composite. A simple modeling approach has been developed that allows one to predict the dynamic mechanical properties of a particle-reinforced metal-matrix composite given only the properties of the matrix phase. jg

Descriptors :   *SHEAR PROPERTIES, *DEFORMATION, *HIGH PRESSURE, *TUNGSTEN ALLOYS, VELOCITY, MEASUREMENT, MECHANICAL PROPERTIES, RECOVERY, HIGH RATE, MODELS, HAFNIUM, DYNAMICS, COMPOSITE MATERIALS, PROJECTILES, MODEL THEORY, TEST METHODS, METAL MATRIX COMPOSITES, MATRIX MATERIALS, PHASE, STRAIN RATE, IRON, RESPONSE, SAMPLING, PARTICULATES, NICKEL, DUAL MODE, ADIABATIC CONDITIONS, RADIAL FLOW, HYDROSTATIC PRESSURE.

Subject Categories : Properties of Metals and Alloys
      Inorganic Chemistry
      Physical Chemistry
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE