Fatigue Crack Growth Behaviors in Novel TC32 Titanium Alloy with Bimodal and Basket-Wave Microstructures

Abstract

This article investigated the fatigue crack growth behaviors in the novel TC32 titanium alloy with bimodal and basket-weave microstructures, which were respectively obtained by the convectional (α+β) phase forging and quasi-β forging processing. Results showed that at the same level of tensile performance, the basket-weave microstructure had a lower fatigue crack growth rate than the bimodal microstructure, as the basket-weave microstructure had a more tortuous crack path, a rougher fracture surface and more secondary cracks. All these served to improve the fatigue crack growth resistance, which attributed largely to the effects of crack closure. Moreover, secondary cracks grew primarily along the α/β interfaces for the basket-weave microstructure but directly went across the colony-type lamellar (α+β) phase and the primary α phase without obvious regularity for the bimodal microstructure.