Effects of Nb and o Contents on the Negative Linear Thermal Expansion Behaviors of Cold Rolled Ti-34Nb Alloys

Abstract

In this study, the effects of Nb and O contents on the negative thermal expansion behaviors including the coefficient of negative thermal expansion and matensite (α) stability of cold rolled (CR) Ti-34Nb alloys was investigated by optical microscopy, X-ray diffraction and Thermomechanical analysis. Results show that texture strength of CR-Ti-xNb-xO alloys is related to β stability, the addition of Nb and O (β stabilizers) enhances the texture strength. XRD results indicate that Nb and O inhibit the formation of α. The coefficient of negative thermal expansion of CR-Ti-xNb-xO alloys decrease with the increase of Nb and O contents. Moreover, cyclic thermal expansion results reveal that Nb and O promote the decomposition of α.