Crack propagation in gradient microstructures in titanium alloys

摘要

Microstructural gradients were developed in the near- #alpha# titanium alloy TIMETAL 1100 and the metastable #beta# alloy Ti-3Al-8V-6Cr-4Mo-4Zr (Beta C) by thermomechanical treatments. In TIMETAL 1100, the prior #beta# grain size of fully lamellar microstructures was varied over the cross-section of specimens, while for Beta, C the degree of age-hardening was varied within the case of deep-rolled notched specimens. These microstructural gradients can result in a combination of excellent fatigue performance and outstanding fracture toughness for components that can not be achieved by non-gradient microstructures.