Diffusion brazing of high temperature alloys
Description / Outline
Diffusion Brazing is a joining technique for nickelbase superalloys. There are two possible fields of application: Repair of turbine blades and production of “fabricated components”. During repair processes cracks that evolved in operation are closed. The big difference between the two applications is the width of the joint. For repairing the major point is to close even big gaps in acceptable times. While for the fabrication of new components the use advantageous small gaps is possible. There exist different melting point depressants for diffusion brazing: new innovative ones like germanium while conventional brazes use boron. In contrast to boron germanium does not form any brittle phases in nickelbase superalloys.
Research at WTM covers both areas. The aim for conventional brazes which contain boron is to improve the microstructure and the mechanical properties of the joint via an appropriate processing route. The development with Germanium as melting point depressant is not as advanced. Here different adequate brazes on basis of the brazed superalloy are generated and their behavior regarding brazing time and temperature are characterized.