Tensile Deformation Behavior and Dynamic Recrystallization of TA15 Alloy over a Wide Temperature Range

TA15 is a near-α titanium alloy that is used extensively in the manufacturing of high-temperature structural components and has important applications in the aerospace field. Herein, the tensile deformation behavior of a TA15 alloy with equiaxed α grains is investigated over a wide temperature range of 25–900 °C. Based on the microstructural observations and tensile testing results, the deformation behavior of the TA15 alloy is classified into four stages: 1) deformation strengthening stage at 25–550 °C; 2) α-phase softening stage at 600–650 °C; 3) phase transition softening stage at 700–800 °C; and 4) dynamic recrystallization stage at 850–900 °C. The α→β phase transition occurs predominantly between equiaxed α grains, and the increase in β-phase content results in further enhancement of alloy plasticity. Dynamic recrystallization occurs first at the edge of the equiaxed α grains and gradually extends into the grain interior. The size of the dimples on the fracture surface increases gradually as the temperature increases, and a large shearing and splitting area is observed at 600 °C due to α-phase softening.