A novel constitutive model for hot deformation behaviors of Ti-6Al-4V alloy based on probabilistic method

The flow behaviors of Ti-6Al-4V alloy are studied by isothermal compressive experiments at the deformation temperature from 850 to 950 C and strain rate from 0.001 to 1 s^-1. To analyze the uncertainties induced by material itself and testing procedure, repetitive compressive tests are conducted under each experimental condition. It is found that the uncertainties of flow behaviors are too great to be ignored. The innovation of the study is that the probability theory is introduced to model flow behaviors. 3¹² (=531,441) sets of flow curves are created by the resampling method, in which 10,000 sets are used to determine the material parameters of constitutive equations. Therefore, the probability densities of material parameters can be easily obtained. It is found that the probability density functions of the most material parameters are similar to the normal distribution. The values of material parameters with the maximum probability density are selected for the established constitutive model. The advantage of the established constitutive model is that it can describe the most probable flow characteristics of Ti-6Al-4V alloy. (orig.)