The mechanical response of titanium alloys to dynamic impacts in a wide temperature range

Abstract

The paper presents the results of numerical simulation mechanical behavior hexagonal close packed titanium alloys under dynamic loadings in a temperature range up to temperature of alpha-beta phase transitions. The model of a damaged medium was proposed to describe the response of titanium alloys VT1-0, VT5-1, VT6 at high strain rates and at elevated temperatures. The model takes into account the change in the contributions to the flow stress from the mechanisms of twinning and dislocation slip in the considered subgroup of hexagonal close packed alloys. Thus, it was possible to increase the accuracy of predicting of dynamic fracture of titanium under tensile loads, including the spall fracture. The model allows describing both spall fracture and tensile fracture at high strain rates under conditions of a complex stress state. The constitutive equation takes into account the change in flow stress in wide range of a cumulative plastic strain, a homologous temperature, and the logarithm of the normalized equivalent strain rate. The influence of the damage parameter, the stress state triaxiality parameter on the flow stress is taken into account by the Gurson–Tvergaard’s model. These inelastic strains occur during repeated loading of the alloy in reflected loading and unloading waves.