THE SUBSTRUCTURE OF CU3AU AFTER TENSILE DEFORMATION AND SHOCK LOADING,
NORTHWESTERN UNIV EVANSTON ILL DEPT OF MATERIALS SCIENCE
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Optical and transmission microscopy and x-ray diffraction were employed to study the substructure. Specimens were also deformed in ordinary tension at 77 K and 298 K for comparison. There was no sudden increase in the dislocation densities or marked change in dislocation arrangement in the shock-loaded specimens corresponding to the rise in energy and resistivity. The dislocation densities for both initial states were similar and of the order of 10 to the 11th power per sq cm after a shock of 370kb, only about 30 pct. greater than the densities found in ordinary tensile testing of Cu3Au to the same strain. Antiphase domain boundaries were created in the ordered alloy on both 001 and 111 planes, with about equal probability during shock loading and the probabilities of these boundaries were an order of magnitude greater than after ordinary tension to the same strain. After tensile testing at 77 K the antiphase boundaries were primarily on 111, but at 298 K these were primarily on 001. The degree of long-range order was 0.6 after 25 pct. strain by shock loading, but 0.95 after tensile deformation to this strain. Disordering was due to the creation of these boundaries. Work hardening was not affected by them.