MICROSTRUCTURE, TENSILE, AND CREEP BEHAVIOR OF Ti-15Al-33Nb (at percent) AND Ti-21Al-29Nb (at percent) ORTHORHOMBIC+BCC ALLOYS

摘要

In this work the creep and elevated temperature tensile behavior of two orthorhombic (O)+body-centered-cubic (BCC) alloys, specifically Ti-15Al-33Nb(at percent) and Ti-21Al-29Nb (at percent), were evaluated in order to determine the effect of alloy composition and microstructure on the mechanical properties and deformation behavior. Tensile tests, performed at RT and 650 deg C, indicated that the Ti-21Al-29Nb alloy exhibited significantly lower elongation-to-failure values than the Ti-15Al-33Nb alloy. Heat-treatments used to precipitate greater volume fractions of the O-phase resulted in greater strength levels, while the BCC phase provided ductility. The measured creep stress exponents (l.l