Microstructure and Mechanical Properties of a Nickel-based Honeycomb Sandwich at High Temperature

Abstract

A nickel-based superalloy honeycomb sandwich was manufactured by high-temperature brazing. The microstructure and the out-of-plate mechanical properties were determined for honeycomb sandwiches at high temperature. The maximum tensile stress was 28.5 MPa and the compressive yield strength was 29.6 MPa for the specimens at room temperature. These parameters decreased to 23 MPa and 25 MPa for specimens at 550°C, to 13.8 MPa and 19.6MPa for specimens at 850°C and to 9.3 MPa and 15.9 MPa for specimens at 900°C, respectively. With increasing temperature, the tensile elongation increased, then declined; the tensile elastic modular and the compressive modular decreased. There are intermetallic compounds and a eutectic structure in the brazing region and the critical brazing clearance is 20 μm.