Estimation of dislocation density of commercially pure titanium in ECAP process by combining finite element simulation with a dislocation-based model

In this research, by combining mathematical models based on the deformation mechanisms with finite element simulation of the deformation process, for the first time, the dislocation density content of commercially pure titanium was calculated and analyzed during its processing by the process of equal channel angular pressing (ECAP). For this purpose, first, the deformation behavior of commercially pure titanium during the ECAP process was simulated using ABAQUS software. In the next step, this information obtained from simulation was used as inputs to the mathematical model to estimate the dislocation density of the metal. A twodimensional simulation was carried out. In simulation, ECAP was performed at 250°C and in a die with a channel angle of Φ = 105 and a corner angle of Ψ = 20 degrees. In addition, ECAP was conducted up to 5 consecutive passes using two different processing routs A and C on the samples. Then, by using the mathematical model, the values of the dislocation density created in the samples were evaluated after different ECAP passes. The results indicate that by applying 5 ECAP passes using route C the mean dislocation density of titanium increases from the initial value (0.3× 1012 m-2) to 4.64 ×1015 m-2. Also, when ECAP is conducted by route A it leads to 10% higher density than route C. The distribution of dislocation density throughout the Ti bars has a good uniformity, except for a few millimeters from the beginning and end regions of the bars.