ELECTRON BEAM JOINING OF γ-TITANIUM ALUMINIDE

摘要

From the economic and also from the production point of view, the development of suitable joining techniques is a decisive factor for industrial application of γ-titanium aluminide. The excellent properties of titanium aluminide such as high specific strength, high temperature loads and creep resistance shall be maintained in the joined zone. The brazing process by electron beam offers some advantages in comparison to other joining processes. These advantages are the use of vacuum instead of atmosphere, the precise energy input and the low cycle times. Materials' high brittleness and thus susceptibility to cracking are a challenge for brazing with high cooling rates. The adapted beam deflection for process-integrated post- or preheating is one solution to achieve a high strength in the joints. The selection of the brazing filler metal is important for high strength especially in dissimilar material joints like titanium aluminide with steel or titanium aluminide with nickel based alloys. In this presentation, suitable joining strategies for dissimilar joints of modern γ-titanium aluminides (alloy TMN) with nickel based alloy as well as heat treatable steel via electron beam are presented. Different joints are analysed in detail for example by cross sections, scanning electron micrographs and shear tests.