Distribution of nanodomains in heterogeneous Ni-superalloys: Effect on microstructure and mechanical deformation

In this work, four distinct heterogeneous nanostructured Inconel 725 films synthesized via magnetron sputtering, feature an extensive array of nanodomains including abnormally large grains, heterogeneous precipitation, rafted structures, and both growth and annealing nanotwins. By leveraging the substrate type used during deposition, films with different stress profiles were produced, resulting in fully nanotwinned films with either coarse or fine grain widths in the as-prepared state, and heterogeneous nanostructured films with either a uniform or gradient feature size distribution after heat treatment. Thorough microstructural characterization was used to identify the types of nanodomains in each sample. The type of microstructure produced was found to have important consequences on mechanical behavior and plastic deformation. These findings provide insight on how to alter the distribution of nanodomains, as well as how their arrangement and interactions can affect deformation behavior in heterogeneous nanostructured Ni-superalloys.