Fast Epitaxial High Temperature Brazing of Single Crystalline Nickel Based Superalloys

Abstract

A new high temperature brazing technology for the repair of turbine components made of single crystalline nickel based superalloys has been developed. It allows the repair of single crystalline parts by producing an epitaxially grown braze gap within very short times. In contrast to commonly used brazing technologies, the process is not diffusion based but works with consolute systems, particularly nickel-manganese alloys. Brazing experiments with 300 μm wide parallel braze gaps, as well as V-shaped gaps with a maximum width of 250 μm, were conducted. Furthermore, thermodynamic simulations, with the help of THERMOCALC software, Version TCR, were carried out to identify compositions with a suitable melting behavior and phase formation. With the new alloys complete, epitaxial bridging of both gap shapes has been achieved within brazing times as short as 10 min.