Effects of Rolling and Heat Treatment on the Microstructure and Mechanical Properties of Newly Designed High-Temperature Titanium Alloy in Plate Manufacturing

The alloy SJ1100, independently developed by Zhejiang Shenji Titanium Industry Co., Ltd, is a new type of lightweight, high-strength, high-elasticity titanium alloy with independent intellectual property rights. Rolled SJ1100 titanium-alloy plates and sheets were manufactured with different processes and parameters, and their microstructure and uniaxial tensile properties were characterized and compared by using metallography, scanning electron microscope, electron backscattering diffraction and tensile tests. The 2-mm sheet annealed at 820 °C for 40 min and straightened at 600 °C for 4 h exhibited the highest yield strength and ultimate tensile strength as well as the lowest ductility, while the 30-mm one annealed at 820 °C for 40 min and aged at 600 °C for 16 h exhibited the lowest yield strength and ultimate tensile strength with the highest ductility. Straightening is thought to be more deleterious to ductility compared with aging. Annealing after straightening decreases the average grain size, lowers the intensity level of texture, and relieves the residual stress of the sheet. A larger plastic deformation results in an energetically more unstable regime, which makes the sheet easier to recrystallize during annealing.