Investigation on Hot Workability of Ti-37 At Pct Nb Alloy Based on Processing Map and Microstructural Evolution

Ti-37 at pct Nb alloy has been successfully applied to engineering fields because of its excellent superconductivity and perfect ductility. The TiNb alloy is necessary to optimize hot processing parameters and further investigate hot workability. Consequently, a processing map of TiNb alloy is constructed based on dynamic material modeling via stress-strain curves at 700 degrees C to 1000 degrees C and 0.0005 to 0.5 s(-1). The results show that one appropriate working domain is where the temperature range is about 765 degrees C to 910 degrees C and the strain rate is simultaneously < 0.0007 s(-1), and another appropriate working domain is where the temperature range is about 960 degrees C to 1000 degrees C and simultaneously the strain rate range is about 0.002 to 0.1 s(-1). Microstructures of TiNb samples, which are deformed in the instability processing domain with the high strain rate of 0.5 s(-1), are further characterized to reveal dependence of the processing map on microstructures, and thus it is found that dynamic recovery and incomplete dynamic recrystallization cannot effectively improve the heterogeneous microstructure of TiNb alloy samples during deformation under a high strain rate. In addition, theta- and gamma-fiber textures are found in the deformed TiNb specimens, and high deformation temperature contributes to the formation of the theta-fiber texture. (C) The Minerals, Metals & Materials Society and ASM International 2021

Automated summary

The Ti-37 at pct Nb alloy has been successfully applied to engineering fields due to its excellent superconductivity and ductility. A processing map based on dynamic material modeling via stress-strain curves has been constructed to optimize hot processing parameters for the TiNb alloy. The study shows that the alloy has two appropriate working domains, with high deformation temperature contributing to the formation of fiber textures, but dynamic recovery and incomplete recrystallization are ineffective at high strain rates.