Effects of shock prestrain on the mechanical behavior of tantalum and tantalum-tungsten alloys

The effects of shock prestrain on the mechanical behavior and microstructure of annealed tantalum and Ta-W alloys have been examined. The test material was shocked to 45 GPa for 1.8 mu s and soft-recovered such that deformation that occurred during this procedure was predominantly due to the shock loading. Mechanical characterization of the annealed and shock-recovered tantalum was performed over a wide range of strain rates (10(-3) to 7000 s(-1)) in compression. Shock prestraining caused an increase in the yield and flow stress in all of the test materials. The test results suggest that the athermal component of the flow stress is altered and to some extent work hardening is exhausted. The effects of shock prestrain on the microstructure and substructure of the test material were examined using optical microscopy, which revealed features which may be deformation twins. The results of these examinations and how they correlate with the effects of shock prestrain on mechanical behavior are discussed.