THE ROUGHNESS IN THE DIFFUSION WELDING OF TI-6AL-4V ALLOY

In this study, we show that the surface finish plays an important part in diffusion welding of titanium alloys. The welded surface area in t itanium alloys increases when the finish roughness R decreases and rea ches 100% of the surface when roughness is lower than the titanium aut o diffusion X. The ratio X/R defined above seems to play a particular part in weld quality (X = autodiffusion distance of titanium, R = roug hness of the surface). In the case of joints between the beta (beta) p hase, no defect is observed for values superior to one. For values bel ow one, defects become larger and more numerous. Therefore, this param eter seems to express the effects of time, temperature and surface fin ish.