Instrumented anvil-on-rod tests for constitutive model validation and determination of strain-rate sensitivity of ultrafine-grained copper
✍ Scribed by M. Martin; A. Mishra; M.A. Meyers; N.N. Thadhani
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 955 KB
- Volume
- 464
- Category
- Article
- ISSN
- 0921-5093
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✦ Synopsis
Anvil-on-rod impact tests were performed on as-received (cold-rolled) OFHC copper rods and copper processed by 2-or 8-passes of equal channel angular pressing (ECAP). The average grain size ranged from ∼30 m for the as-received sample to ∼440 nm for the 8-pass sample. The dynamic deformation states of the samples were captured by high-speed digital photography and velocity interferometry was used to record the sample back (free) surface velocity. Computer simulations utilizing AUTODYN-2D hydrocode with the Johnson-Cook constitutive model were used to generate free surface velocity traces and transient deformation profiles for comparison with the experimental data. The comparison of experimental results with AUTODYN simulations provided a means for extracting the strain-rate sensitivity of copper as a function of grain size. Strain-rate sensitivity was found to increase as grain size decreased.