Youngʹs modulus measurement and study of the relationship between mechanical properties and microstructure of air plasma sprayed alloy 625

The present study is a continuation of the previous research on fabrication of sandwich structures suitable for high temperature applications. The overall performance of sandwich constructions depends on the material properties of skin and core, and their geometrical characteristics. The sandwich structure consisting of a Ni alloy foam covered by alloy 625 is expected to be a good candidate for high temperature applications. Amongst various methods of applying alloy 625 skin on the foam core, thermal spray techniques are the most promising for the rapid deposition of thick sections on the both sides of the foam structure. Microstructural characteristics of alloy 625 coatings on Ni alloy foam have been previously reported. The objective of this investigation was to characterize the mechanical behavior of air plasma sprayed (APS) alloy 625 coatings deposited on Ni alloy foam. The results of tensile tests performed on the free standing as-sprayed and heat treated alloy 625 coating samples are reported. Furthermore this paper examines the available models relating the microstructure to the elastic modulus, E, of the coatings to predict mechanical behavior of alloy 625 coating. Finally, numerical results from finite element analyses performed on the coatings are presented in this study. Comparison between the results of the tensile tests, theoretical models, and numerical simulations obtained from finite element methods will help us to understand microstructural basis of the mechanical characteristics of alloy 625 coating structure.