The effect of mixed mode I/III loading on the fracture toughness of Timetal 834 titanium alloy

The effect of mixed mode I/III loading on the fracture toughness of Timetal 834 titanium alloy plate was investigated. The fracture toughness of Timetal 834 alloy was found to remain more or less unchanged initially and subsequently increase with increasing mixed mode I/III loading. Formation of quasi-cleavage facets at primary α grains was found to be the most important step in the fracture process. This coupled with the nature of the stress field ahead of the crack tip under mixed mode I/III loading was then used to explain fracture toughness behaviour with increasing mixed mode I/III loading in Timetal 834 titanium alloy.