Electron beam welding and brazing of gamma-titanium aluminide for linear and circumferential joints

摘要

From the economic and also from the production point of view, the development of suitable joining techniques is a decisive factor for the industrial application of gamma-titanium aluminide (TiAl). The excellent properties of titanium aluminide with high niobium content of 5 - 8%, such as high specific strength, high temperature loads, creep resistance and also the resistance to oxidation shall be maintained in the joining point. Materials' high brittleness and thus susceptibility to cracking are a challenge for welding with high cooling rates. The melting in the fusion zone is changing the material properties by segregation and diffusion. In order to avoid those problems, the process control is very important in joining. It is, for example, possible to approximate the microstructure in the joining zone to that of the base material via the application of a suitable, process-integrated beam deflection or via post- or pre-heating. In this publication, suitable joining strategies for the welding and brazing of modern gamma-titanium aluminides (TNB V5) via electron beam are presented.