Effect of microstructures on the dynamic deformation behavior of Ti-6A1-4V alloy

Abstract

The effects of microstructures of Ti-6A1-4V alloy on the flow stresses and fracture behaviors at quasi-static and dynamic deformation conditions were investigated. Specimens of different sizes and fractions of a globules in equiaxed and bimodal structures were compressed at the strain rate of 2x 10(-3)/s and 3x10(3)/s using hydraulic testing machine and split Hopkinson pressure bar, respectively. The a globule size in equiaxed structure changed the level of flow stresses, but did not affect the strain hardening characteristics. Meanwhile, the volume fraction of a globule (or lamellar phase) in bimodal structures influenced both the flow stress and strain hardening exponent at quasi-static and dynamic deformation conditions. Bimodal structure of 50% lamellar fraction is considered to be more favorable in dynamic deformation condition at strain rate regime of 3x10(3)/s than equiaxed or bimodal one having higher lamellar fraction.