Flexural properties of sandwich beams consisting of air plasma sprayed alloy 625 and nickel alloy foam

Sandwich structures are considered as viable engineering constructions due to their unique structural, physical, and mechanical properties. An investigation of the mechanical characteristics of sandwich structures suitable for high temperature application is presented. A process has developed to produce high temperature sandwich structures by depositing alloy 625 skins on Ni alloy foam cores using air plasma spraying (APS). The experimental investigation consisted of fabrication of sandwich structures and testing of mechanical performance of sandwich specimens under flexural loading conditions. The responses of the as-fabricated sandwich structure to heat treatment were investigated. The strength of the sandwich structure was significantly increased after heat treatment. The influence of skin thickness on mechanical behavior of sandwich structures was examined by performing four-point bending test on sandwich samples with skin thicknesses of 0.5 and 0.1 mm. The larger the skin thickness, the higher the strength of the sandwich beams. Comparison between the results of four-point bending tests on sandwich structures with different skin thicknesses will help us to understand the effect of skin thickness on the failure mechanism of sandwich structures.