Structural evolution of materials in thick-walled cylinder test
- Institute of Hydrodynamics, Novosibirsk (Russian Federation)
- Univ. of California, San Diego, CA (United States); and others
The {open_quotes}Thick-Walled Cylinder{close_quotes} method, based on cylindrical pore collapse, with the help of low detonation velocity explosive, was used to investigate structural evolution of solid materials (copper, tantalum, titanium, stainless steel) during the process of high-strain-rate plastic deformation with overall shear strain > 10 and strain rates 10{sup 4} - 10{sup 5} sec{sup -1}. Critical conditions for shear localization are discussed in dependence on initial structural parameters and their evolution during the deformation with emphasis on the dynamic recrystallization process. Tantalum was investigated more extensively. In order to simulate the thermomechanical environment experienced by shaped charges and EFP`s, the tantalum was tested in both as-received and shocked (P = 40 GPa; tp {congruent} 1.5 {mu}s) conditions. The microstructure evolved in the following sequence as the plastic strain was increased; dislocation cells {yields} subgrains {yields} dynamic recrystallization (micrograms) {yields} static (postdeformation) recrystallization. The material exhibited grain-scale localization beyond a critical plastic strain which resulted in considerable heterogeneity of plastic deformation and affected the failure, by the creation of periodic soft regions.
- OSTI ID:
- 175197
- Report Number(s):
- CONF-950686--; CNN: Contract DAAL 03-92-G0108
- Country of Publication:
- United States
- Language:
- English
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