Effect of Hot Work on Stress Rupture Properties of Electron Beam Welds of Ti-24Al-15Nb-1.5Mo/TC11 Dual-Alloy

The effect of hot working conditions on the stress rupture properties of Ti-24Al-15Nb-1.5Mo/TC11 dual-alloy with electron beam welds has been evaluated. Under the gradient heat treatment, the stress rupture properties of the dissimilar alloy joints with 40% deformation degree are superior to the others. The weld and heat affected zone (HAZ) are the weak areas in the stress rupture experiment. The microstructures of weld and HAZ containing grain boundary α are not beneficial to the stress rupture property. Meanwhile, the grain boundaries of Ti-24Al-15Nb-1.5Mo base alloy with coarse α2 phases have a negative effect to stress rupture property. As the atoms diffusing, the content of Nb increases obviously in the weld after stress rupture experiment.