Deformation and Failure Mechanism of U-Ti Alloy by SHPB

The compression behavior of U-Ti alloy was investigated over a wide range of strain rates from 10(-3) to 10(3) s(-1) by static compression tests and split hopkinson pressure bar (SHPB). Combined with the strain frozen technique and the optical micrography, the microstructure evolution of cylinder specimens with section plane was in-situ observed during the repeated loading/unloading process. Results show that U-Ti alloy is a strain-rate sensitive material. The yield strength and the flow stress increase with the strain rate increasing, while the strain rate has little influence on the strain hardening behavior. There is a sudden rise in yield strength and flow stress while the strain rate reaches to 7500 s-1. Adiabatic shear bands are observed in U-Ti alloy samples deformed at very high strain rates, whose initiation is caused by the development of microcracks. Finally, the Johnson-Cook model was used to describe the mechanical response of U-Ti alloy and the fitted results are in good agreement with the experimental.