Superalloy Honeycomb Research Articles

Microstructure evolution and mechanical properties of nickel based honeycomb sandwich

A nickel based superalloy honeycomb sandwich was manufactured by high temperature brazing. The microstructure evolution and the out of plate mechanical properties were investigated for honeycomb sandwiches aged at 1000°C in the present paper. 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 22·9 and 20·5 MPa for specimens aged for 2 h, to 18·2 and 12·2 MPa for specimens aged for 5 h and to 20·2 and 14·3 MPa for specimens aged for 10 h respectively. With increasing aging time the tensile elongation decreased, the intermetallic compounds and the eutectic structure in the brazing region disappeared, and the solid solution approaching the matrix gradually increased.

Microstructural evolution and mechanical properties of a nickel-based honeycomb sandwich

A nickel-based superalloy honeycomb sandwich was manufactured by high-temperature brazing. The microstructural evolution and the out-of-plate mechanical properties were determined for honeycomb sandwiches aged at 800 °C. The maximum tensile strength was 28.5 MPa and the compressive yield strength was 29.6 MPa for the original specimens. These parameters decreased to 24.7 MPa and 23.5 MPa for specimens aged for 10 h, to 24.9 MPa and 21.5 MPa for specimens aged for 20 h and to 26 MPa and 24.8 MPa for specimens aged for 30 h, respectively. With increased aging time the tensile elongation decreased, the intermetallic compounds and the eutectic structure in the brazing region disappeared, and the solid solution approaching the matrix gradually increased.

A study on metallic thermal protection system panel for Reusable Launch Vehicle

A Ni-based superalloy honeycomb thermal protection system (TPS) panel has been fabricated. And a curved Ni-based superalloy honeycomb sandwich has also been fabricated. The preliminary thermal insulation results of a fabricated Ni-based superalloy honeycomb TPS panel (the areal density of this panel is 6.7kg/m2 and total height is 32mm) indicate that the maximum temperature of the lower surfaces of the panel is lower than 150∘C when the temperature of outer surface is held at 650∘C for 30min. The flatwise tensile strength and compressive properties of a fabricated Ni-based superalloy honeycomb sandwich coupon was studied at room temperature. A multilayered coating has been developed on the surface of the superalloy honeycomb TPS panel for environmental protection and thermal control. The oxidation weight-change results show that the weight change of the Ni-based superalloy honeycomb sandwich with the oxidation resistant coating is extremely small at 1100∘C in air for 10h. The emittance layer of the multilayered coating imparts an emittance in excess of 0.85 during exposure at 850∘C, which was at least 14% greater than that of the substrate with oxidation resistant alone.

Acoustic testing of high-temperature panels

Results are presented of a series of thermal-acoustic tests conducted on the NASA Langley Research Center Thermal-Acoustic Test Apparatus to (1) investigate techniques for obtaining strain measurements on metallic and carbon-carbon materials at elevated temperature; (2) document the dynamic strain response characteristics of several superalloy honeycomb thermal protection system panels at elevated temperatures of up to 1200 F; and (3) determine the strain response and sonic fatigue behavior of four carbon-carbon panels at both ambient and elevated temperatures. A second study tested four carbon-carbon panels to document panel dynamic response characteristics at ambient and elevated temperature, determine time to failure and faliure modes, and collect continuous strain data up to panel failure. Strain data are presented from both types of panels, and problems encountered in obtaining reliable strain data on the carbon-carbon panels are described. The failure modes of the carbon-carbon panels are examined.