Research of Microstructure Evolution of Damage Tolerance Titanium Alloy TC4-DT during Grain-Refining and Homogenizing

The microstructure evolution of damage tolerance titanium alloy TC4-DT during grain-refining and homogenizing deformation process has been studied in this paper. The results showed that, when the alloy was deformed at 950℃～975℃ in single  phase, dynamic recrystallization would occur simultaneously with grain-boundary-phase breaking and inner-grain refining process and would lead to significant grain-refining and homogenizing effects, which had also been verified in the deformation of a TC4 titanium ingot. With the increase of forging deformation, the alloy’s microstructure was refined with the result of decrease in ultrasonic noise value and increase in tensile plasticity after subsequent quasi- heat treatment. Low noise value in ultrasonic detection is an important guarantee for safe and reliable applications of large scale aviation-oriented structures.