Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti-1300 Alloy by Electron Beam Weldment

The microstructures and mechanical properties of electron beam weldment Ti-1300 alloy after or before different heat treatments were investigated. The results indicate that the various heat treatments before welded treatment cause little effect on microstructures and mechanical properties for different samples. The fusion zone microstructure of heat treatment (NHT) specimen after welded treatment is mainly composed of columnar beta grain and beta subgrain with big size, and there is small amount of alpha phase distributing at high-angle boundary in the fusion zone. The microstructure leads to low strength and elongation in comparison to matrix. For the welded specimens after various heat treatments, the morphology and size of columnar beta grain or beta subgrain, and the distribution of alpha phase during heat treatment can not be changed. However, the morphology, size and quantity of a phase can be adjusted for different heat treatments, and determine the mechanical properties of weld joint zone. For the welded samples after annealing or aging treatment, alpha phase shows high strengthening effect in comparison to matrix, which results in the failure occurrence in matrix.