Time Dependent Twinning and the Role of Oxygen in the Low Temperature (<0.25 Tm) Creep Behavior of Alpha Titanium Alloys

Abstract

Creep behavior in titanium alloys is critical across a broad range of applications. The microstructure and deformation mechanisms in alpha-titanium alloys contribute significantly to creep behavior and thus merit careful study in order to design and deploy improved titanium alloys. While often thought to respond almost instantaneously to loading, we will present experimental work demonstrating that twins can grow very slowly in alpha titanium alloys and that this time dependent twinning correlates with increased low temperature (<0.25 Tm) creep strain during testing. Further, through the use of density functional theory calculations in combination with other computational tools, we will present details on the interaction of oxygen interstitials with twins in titanium alloys, provide insight into the role of oxygen in creep deformation, and discuss plausible development paths to improve performance.