Abstract for the Institute Notice:
High entropy alloys (HEAs) opened wide opportunities to research on fundamental and technological applications. The presence of multiple elements and simple crystal structures in HEAs resulted in superior mechanical properties, especially at high temperatures. These properties mainly depend on the composition and microstructural stability, which is primarily influenced by the elemental behaviour within solid solutions. Hence it is important to understand the interactions among the alloying elements and their activity/mobility inside the matrix. Diffusion studies are a very powerful and sensitive tool to understand the fundamental behaviour of atomic mobilities, kinetic and thermodynamic interactions and their influence on microstructural stability.
The present study highlights a novel alloy design of HEAs to obtain ordered pseudobinary multicomponent aluminides and is focused on their underlying diffusion behaviour. The microstructure and sublattice ordering in multicomponent alloysstarting from binary to hexanary B2 aluminidesare studied. Tracer diffusion of the57Co, 59Fe, 54Mn, 63Ni and 65Znradioisotopes is measured overa wide temperature interval and the activation energies of volume diffusion are estimated.Diffusion in multicomponent B2 ordered alloys is found to be faster in comparison to binary AlNi.Furthermore, the tracer diffusion coefficients are measured under a chemical gradient combining inter- and tracer diffusion techniques in Al(Fe,Ni) system. The measured diffusivities are correlated with the presence of elements and the type of defects that they generate.