Fracture Toughness Phenomena in an Unaged Beta Titanium Alloy

Abstract

The fracture toughness behavior of a commercial beta titanium alloy, Ti-3Al-8V-6Cr-4Zr-4Mo, has been examined between −196°C and 380°C, The observed tough-brittle transition results from increasing amounts of intergranular and cleavage fracture with decreasing temperature. Crack initiation is associated with particle/matrix interface parting, while cleavage crack propagation at low temperature requires the attainment of a critical stress over a characteristic distance. Micromechanical modeling of the principal fracture event associated with critical stress cleavage crack propagation does appear to accurately predict the magnitude of this distance, although it is limited to initiation controlled cleavage fracture events.