Texture prediction method in thermoplastic large deformation process of near-alpha type titanium alloy

Abstract

The invention provides a texture prediction method for a near-alpha type titanium alloy in a thermoplastic large deformation process, and belongs to the technical field of plastic forming. The method comprises the following steps: firstly, obtaining stress-strain data of the near-alpha type titanium alloy, Bunge Euler angles of textures before and after thermal simulation of large deformation and volume fractions of alpha and beta phases by utilizing a uniaxial isothermal constant-strain-rate thermal simulation stretching / compression test, an electron back scattering diffraction technology and an optical microscope; obtaining a velocity gradient tensor value and a time increment in the thermoplastic large deformation process of the near-alpha type titanium alloy through numerical derivation and post-processing; and finally, determining and optimizing parameters of a mechanical threshold stress hardening rule by combining the stress-strain data and the Bunge Euler angle of the texture before and after thermal simulation of large deformation, and establishing an ABAQUS-VPSC-MTS multi-scale model. The model can predict the texture of the near-alpha type titanium alloy in the large deformation process, can analyze the plastic deformation mechanism, the macromechanical behavior and the texture evolution law in the deformation process, and is beneficial to achieving the purpose of shape-property integration of plastic processing products.

Description

technical field [0001] The invention relates to the technical field of plastic forming, in particular to a texture prediction method in the process of large thermoplastic deformation of near-α-type titanium alloys. Background technique [0002] Titanium and titanium alloys have a wide range of uses in key fields such as air, sky, earth, and sea because of their light weight, high strength, heat resistance, corrosion resistance, impact and vibration resistance, and good processability required by high-quality structural materials. . Due to the particularity of the hexagonal close-packed (HCP) crystal structure at room temperature, titanium and titanium alloys make plastic deformation difficult and easily form a strong texture, which has a huge impact on the plastic processing and mechanical properties of the product. influences. Therefore, predicting the texture while performing plastic processing under the condition of large thermoplastic deformation plays an important rol...

AI Technical Summary

Problems solved by technology

[0004] Literature 1 (Jie Z, Ll C, Kwa B, et al. Effects of strain state and slip mode on the texture evolution of a near-αTA15 titanium alloy during hot deformation based on crystal plasticity method [J]. Journal of Materials Science&Technology, 2020, 38:125-134.) The texture evolution behavior of TA15 titanium alloy under different high-temperature strain states was analyzed by crystal plastic finite element simulation. Directly simulate the plastic forming process under complex loading conditions, which promotes the development of macroscopic finite element coupled texture simulation methods; literature 2 (Li H, Wei D, Zhang H, Yang H, Liu H, Liu S, Chu Z, Zhang D, Texture evolution and controlling of high-strength titanium alloy tube incold pillowing for properties tailoring, Journal of Materials Processing Tech, 2020, 279) Through the coupling of the three-dimensional finite element model and the viscoplastic self-consistent (VPSC) crystal plasticity model, the deformation is considered History has predicted the non-uniform deformation flow and texture evolution during the cold rolling process of hollow tubes, but cold rolling does not involve the influencing factor of temperature; Document 3 (Chen Liquan. TC18 titanium alloy forging process finite element simulation and texture Prediction [D]. Beijing: University of Science and Technology Beijing, 2019.) simulated the evolution process of the three-dimensional forging texture of titanium alloy TA18 and the compression texture under different conditions and explained the cause of the forging texture, but because the constitutive model used was not The influence of temperature and strain rate is not considered, and tests are required to calibrate a set of model parameters under different deformation conditions

Moreover, none of the above studies considered the volume changes of the two phases of titanium alloys at different temperatures, as well as the influence on the macroscopic mechanical properties and microscopic texture evolution.

Images