학술논문
Direct observations and comparison of crater cross-section microstructures in copper targets for aluminium projectiles impacting at 1.4 and 6.7 km s−1
Document Type
Article
Author
Source
Journal of Materials Science; August 1996, Vol. 31 Issue: 15 p3921-3927, 7p
Subject
Language
ISSN
00222461; 15734803
Abstract
Light and transmission electron microscopy observations of impact crater-related microstructures in copper targets have revealed dramatic differences in the extent and type of microstructures. For a crater formed by a 6.4 mm diameter aluminium (1100) spherical projectile impacting at 1.4 km s−1, a narrow (∼20 μm) recrystallized zone extended axially outward from the crater wall, with dislocation cells which increased in size extending from this zone. By comparison, a crater formed by a 3.2 mm diameter aluminium (1100) spherical projectile impacting at 6.7 km s−1exhibited a recrystallization zone extending more than 200 μm axially from the crater wall, a connecting zone of increasingly dense microbands, having an axial width of about 2000 μm. This zone converged upon a region of dislocation cells which increased in size away from the crater wall. These observations highlight important microstructural differences in cratered metal targets in the hypervelocity impact regime in contrast to the lower-velocity regimes where shock-wave and related ultra-high-strain-rate effects are unimportant.