Investigation of high-temperature deformation strengthening and toughening mechanism of titanium alloy

The materials processed by the method produce a new tri-modal microstructure, which consists of 10-20% equiaxed alpha, streaky alpha and transformed beta matrix. It was found that the higher ductility of tri-modal microstructure is attributed to the equiaxed alpha's cooperative slip and coordinated deformation with the transformed beta matrix. The streaky alpha phases not only increase the strength and cree properties, but also increase the fracture toughness. Propagating along grain boundaries between two neighboring streaky alpha phases, cracks in tri-modal microstructure make a more tortuous way, and then the materials show a higher fracture toughness. This new method is applicable to alpha, near alpha, alpha+beta and near beta titanium alloys.