Weld Repair of Titanium Alloys for Turbine Engine Applications

IBRs represent a great advance for military aero-engine performance. However increased performance has its price: high manufacturing costs and difficulty with in-service repair. Linear friction welding (LFW) and/or high speed machining have reduced manufacturing costs, but service repairs are still significant cost and technical challenges. Current technologies under development include LFW, laser processing, and electron beam processing. These methods can produce metallurgically acceptable welds but are very costly, complex, and not generally compatible with cellular operations. This proposal involves gas metal arc welding – GMAW –with two important innovations: modern adaptively controlled power supplies and a novel in-process quality assurance (IPQA) method that stabilizes the GMAW welding of titanium enabling superior weld properties, minimal spatter/porosity, and control of fusion zone geometry. This advanced GMAW for Titanium is currently being implemented by us for US Army static structural applications, and therefore initial risk reduction work is already in progress. Furthermore, we have successfully applied this method to high rate GMAW processes in aluminum alloys virtually eliminating porosity and spatter. The successful development of this technology for Ti-IBR weld repair would decrease weld repair costs by an order of magnitude, thereby realizing a truly cost-effective IBR repair allowing wider use of this technology.