Fracture Strength of Electron Beam Welded TI6A1-4v and Ti-5a1-2.5sn Alloy Sheet at -423f

摘要

The effect of shallow cracks on the fracture strength of parent metal and electron beam welds in annealed Ti-6Al-4V and Ti-5Al-2.5Sn alloys is presented in this report. Shallow cracks of varying size were induced in parent and weld metal specimens which were subsequently tensile tested at -423F. The critical crack depth of parent metal and electron beam welded Ti-6Al-4V was found to be 0.009 inch deep. As the crack depth increased beyond 0.009 inches, the parent metal and weld metal fracture strength decreased at approximate rates of 5,300 psi per 0.001 inch and 8,700 psi per 0.001 inch, respectively. The critical crack depth of parent metal and electron beam welded Ti-5Al-2.5Sn was about 0.008 inch deep. The fracture strength of parent metal and welds decreased at an approximate rate of 6000 psi per 0.001 inch of additional crack depth. Electron beam welds appear to offer no significant improvement in fracture strength properties over TIG welds. The critical crack size and fracture strength slopes were approximately the same for either process, TIG or electron beam. (Author)