Dynamic Necking of a Near α Titanium alloy at High Strain Rates: Experiments and Modelling

The tensile behaviour of near α Ti3Al2.5V alloy, conceived for applications in aerospace and automotive engineering, is characterized from quasi-static to high strain rates. The material presents noticeable strain rate sensitivity. The dynamic true strain rate in the necking cross-section reaches values up to one order of magnitude higher than the nominal strain rate. It is also observed that beyond necking the true stress-strain curves present limited rate dependence in the dynamic loading regime. The experimental results at various strain rates and temperatures are used to determine the material parameters of a suitable constitutive model for finite element simulations of the dynamic tensile tests. The model predicts the experimentally macroscopic force-time response, true stress-strain response and effective strain rate evolution with good agreement.