Prediction model of tensile mechanical properties of TA15 sheet at room temperature based on internal variables

The sheet specimens of TA15 sheet with different volume fractions of β phase were obtained by vacuum annealing. Then, the stress-strain curves of sheet with different volume fractions of β phase were obtained by tensile test at room temperature, and the true stress after necking was corrected through the well-known Bridgman equations. The results indicate that the tensile strength increases slightly with the volume fraction of β phase. With increasing volume fraction of β phase, the fracture strain increases significantly. Considering the flow behavior of two phases, respectively, a set of constitutive equations coupling dislocation density and damage based on the continuum damage mechanics were developed. The model constants were determined using genetic optimization algorithm (GA). The stress-strain curves of the sheet with 18.63% and 20.04% β phase were used to evaluate the proposed model. The good agreements between the experimental and computed results are obtained.