Microstructure evolution and mechanical properties of nickel based honeycomb sandwich

Abstract

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&degC 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 mechanism during brazing of Hastelloy X superalloy using Ni–Si–B filler metal

“…Therefore, the fabrication of periodic structures from Ni-based superalloys for high-temperature applications opens new opportunities for the use of high-density superalloys in future generations of aircraft/power-generation applications that demand strength and environmental resistance at elevated temperatures along with low weight [3, 4]. Moreover, the honeycomb structures made from Ni-based superalloys are traditionally as an excellent gas flow seal and a sacrificial wear-surface to rotating turbine blades in high-temperature turbines [7, 8].…”

Brazing filler metals

“…Such situations normally see nickel superalloy face sheets and honeycomb cores, which can be brazed with conventional nickel alloys (e.g. ISO 17972-Ni620 [167,178,179] or ISO 17972-Ni650 [176]; ISO 17972-Ni620 can also join stainless steels [180]). Mobile species in nickel brazing can however lead to problematic erosion (which is described in [177]).…”