Research on Microstructure Evolution Rules of TA18 Titanium Alloy Tube During the Differential Heating Push-Bending Forming Process

The evolution of the microstructure of TA18 titanium alloy tube during the differential heating push-bending forming process has a significant impact on its macroscopic mechanical properties. This paper obtained the experimental stress–strain data of TA18 titanium alloy through high-temperature tensile tests, solved the key parameters of the cellular automata (CA) model through fitting calculation, established a finite-element model of differential heating push-bending of TA18 titanium alloy tube using DEFORM-3D, and simulated the evolution of the microstructure during the bending process of the tube based on the CA method. The study investigated the influence of heating temperature, internal pressure, and feed speed of the pusher on the average grain size of the material on the outer side of the bent tube. Experiments were conducted, and the key areas of the manufactured tube were analyzed through metallographic observation. The research indicated that the average grain size of the material on the outer side of the bent tube increases slightly and then decreases with the rise in heating temperature and decreases continuously with the increase of internal pressure or feed speed of the pusher. This study provides theoretical support for optimizing the differential heating push-bending forming of TA18 titanium alloy tube at a microscopic level.