The effect of heat treatment on tensile and creep properties of ''NEAT'' Ti-22Al-23Nb in the transverse orientation

Numerous investigations in recent years have examined continuously reinforced titanium aluminide composites based upon the Ti3Al (α2) matrix phase. The majority of these works emphasize Ti-24Al-11Nb (at%) as a representative matrix alloy for this class. Composites of this type suffer from a number of mechanical performance deficiencies attributed at least in part to the matrix alloy selection. More recent studies have pursued titanium aluminide matrix compositions based upon the ordered orthorhombic (O) phase, Ti2AlNb. Results from studies involving the Ti-22Al-23Nb. Results from studies involving the Ti-22Al-23Nb (at%) matrix alloy suggest that this class offers several benefits when compared to α2-based matrices, including a reduction in fiber/matrix reactivity, increased strength and improved elevated temperature creep performance. A recent study by Smith et. al. utilized a series of post-consolidation heat treatments to successfully modify the matrix microstructure of Ti-22Al-23Nb in neat matrix form. These microstructural modifications were performed on longitudinally oriented specimens and led to improvements in both room temperature tensile strength and elevated temperature creep performance. However, crystallographic and/or mechanical texturing occurring in the foil product may result in anisotropic mechanical performance in the neat matrix. Therefore, the objective of the subject study is to characterize the long transverse orientation and resulting mechanical performance of neat Ti-22Al-23Nb subjected to analogous heat treatments which previously resulted in improvements in both longitudinal tensile and creep performance