Mechanical behaviour and microstructural evolution of Ti-37 at.%Nb alloy subjected to hot compression deformation

摘要

As a typical commercial superconducting alloy, Ti-37 at.%Nb alloy is put into engineering application after it experiences plastic deformation at high temperatures. In order to interpret flow behaviour of Ti-37 at.%Nb alloy at elevated temperatures, the constitutive equation of the alloy is constructed based on compressive test at the temperatures (700-1000 degrees C) and the strain rates (0.0005-0.5s(-1)), where strain compensation is taken into consideration. According to the corresponding constitutive equation, flow stress of Ti-37 at.%Nb alloy is accurately predicted, which is further validated by the experimental data. Simultaneously, the involved microstructural evolution of Ti-37 at.%Nb alloy is characterized in order to further reveal thermal-mechanical behaviour and plastic deformation mechanism of the alloy. Discontinuous dynamic recystallization (DDRX) and continuous dynamic recystallization (CDRX) are found at the same time during hot plastic deformation of Ti-37at.%Nb alloy. Plastic deformation and dynamic recrystallization have a comprehensive influence on textures of Ti-37 at.%Nb alloy. {100}<001>, {100} <011>, {111}<011> and {111}<112> textures are observed in all the deformed Ti-37 at.%Nb samples, where Ti-37 at.%Nb specimens deformed at 700, 900 and 1000 degrees C exhibit the strongest {100} texture, whereas Ti-37 at.%Nb specimen deformed at 800 degrees C shows the strongest {111} texture. (C) 2020 Elsevier B.V. All rights reserved.