Effects of Re-heat Treatment on Microstructure and Mechanical Property of TC4DT Titanium Alloy Plates

摘要

In order to improve tensile properties and to keep good fracture toughness, re-heat treatments were carried out for the β annealed samples cut from TC4-DT plates. Effects of re-heat treatment on microstructures and mechanical properties of TC4-DT titanium alloy were discussed. Solution annealing of the samples in single β phase region and α+β phase region was respectively performed, followed by air cooling or water quenching. Then aging treatment was executed for the samples, followed by air cooling. The microstructure, roomtemperature tensile properties and fracture characteristics under different treated conditions were investigated. The results show that the microstructure of the β re-annealed samples has no remarkable changes. Compared to that of the samples by the air cooling, the refiner secondary α is attained by water cooling. The tensile strength and yield strength of the samples by water quenching increase by about 70MPa compared with the original β annealed samples, whereas the fracture toughness slightly decreases,and the elongation is 8. 5%. Thus the good performance matching is achieved.