THE SUBSTRUCTURE, STORED ENERGY, AND PROPERTIES OF SHOCK-LOADED COPPER.
NORTHWESTERN UNIV EVANSTON ILL DEPT OF MATERIALS SCIENCE
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Changes in stored energy, resistivity, density, x-ray line broadening and dislocation arrangements from transmission electron microscopy have been measured on Cu specimens shock-loaded at 75-435 kb. The stored energy in shock-loaded copper, and changes in density and resistivity are larger than those after conventional deformation. A high density of twins makes an appreciable contribution to all the measured quantities. Dislocation densities rise to values of 10 to the 11th power lines per sq cm at the highest pressure. The resistivity, density and x-ray measurements yield dislocation densities in substantial agreement at all pressures, after correcting for the effects due to the twins. At the higher pressures electron microscopy yields results that are lower by a factor of about 5-10. Dislocation densities from stored energy measurements are high this finding can be rationalized by the consideration that the deformation twin boundaries present are largely incoherent. There is no evidence for homogeneous dislocation nucleation during shock-loading. Author
- Metallurgy and Metallography