Evaluation of A Ti-22ai-23nb “Orthorhombic” Alloy for use as the Matrix in A High Temperature Ti-Based Composite

Abstract

ABSTRACTThe production of titanium aluminide intermetallic compound foil represents a significant manufacturing challenge. Cold rolling, which imparts excellent thickness uniformity and surface finish characteristics that are of benefit in composite fabrication, is especially difficult with these alloys. However, recent modifications in Ti aluminide alloy compositions and advances in thermomechanical processing have made it possible to produce foil of thickness less than 100 μm, having the microstructure and mechanical property characteristics required for composite fabrication and improved performance. This paper describes the properties of a new Ti aluminide alloy, of nominal composition Ti-22AI-23Nb (at.%), comprising a three phase microstructure of α2 (Ti3Al), an ordered orthorhombic phase (Ti2AINb) and an ordered beta phase. The discussion emphasizes the processing of this alloy through cold rolling to foil, and the associated microstructures and mechanical property characteristics that are relevant to the use of this foil to form a composite matrix.