Microstructure evolution and mechanical properties of a nickel-based honeycomb sandwich aged at 900 °C

A nickel-based superalloy honeycomb sandwich was manufactured by high-temperature brazing. The microstructure evolution and the out-of-plate mechanical properties were determined for honeycomb sandwiches aged at 900 °C. The maximum tensile stress was 28.5 MPa and the compressive yield strength was 29.6 MPa for the original specimens. These parameters decreased to 22.2 MPa and 18.8 MPa for specimens aged for 10 h, to 19.3 MPa and15.5 MPa for specimens aged for 20 h and to 20.3 MPa and 16.5 MPa for specimens aged for 30 h, respectively. There was not obvious yield process in all curves of tensile stress versus strain. With increasing aging time, the tensile elongation decreased, and the intermetallic compounds and the eutectic structure in the brazing region disappeared, and the solid solution approaching the matrix gradually increased.