Microstructure evolution of CP titanium during high temperature deformation

Abstract

Purpose: To investigate the superplasticity of commercially pure titanium alloy and microstructure evolution of the alloy during high temperature deformation. Design/methodology/approach: Uniaxial tensile tests were carried out at 600, 750 and 800°C with an initial strain rate from 10-1s-1-10-4s-1. EBSD technology was used to evaluate the microstructure of the commercially pure titanium alloy deformed at high temperature. Findings: It is found that this titanium alloy does not show good superplasticity at 600-800°C due to the rapid grain growth. Studies also show that the dynamic recrystallization took place at high temperatures. The optimum dynamic recrystallization conditions were found to be at 600oC with an initial strain rate of 0.001/s, attaining the highest volume fraction of fine grains whose average grain size is ≈9.7 μm at strain of 80%. This process not only decreases the average grain size of the alloy but also increase the misorientation angle of the grain boundary. Practical implications: The investigations of microstructure of the commercially pure titanium alloy as well as related phenomena during high temperature deformation are important for achieving desired mechanical behavior