Combustion synthesis: a new route for repair of gas turbine components—principles and metallurgical structure in the NiAl/RBD61/superalloy junction

A new technique for repairing turbine blade materials based on combustion synthesis is described in this article. This process uses a local internal generation of heat provided by the NiAl combustion synthesis in order to rebuild damaged turbine components. In this study, a nickel base braze was inserted between a substrate of nickel base superalloy and a powders compact (Ni+Al). The heat released during the combustion synthesis gave rise to interdiffusion of the elements and consequently to formation of a metallurgical bonding. The nature of the phases formed during this process was investigated by the combination of the results of chemical analysis and thermodynamic calculations. In addition to the negligible energy requirement and rapidity of the combustion synthesis, this process allows the local treatment of the turbine components and thus minimises the temperature undergone by the whole piece.