In-situ EXAFS measurements of multi-principal metal alloy under pressure

We propose to perform in-situ EXAFS in CrCoNi alloy during compression in a diamond anvil cell (DAC) to reveal local chemical ordering. We hypothesize that, under GPa pressures, the massively induced dislocations and slip bands will cause a directional version of chemical redistribution. Specifically, rapid Ni diffusion could enable its segregation and ordering along the shear band, in which the deformation strain is highly concentrated. As EXAFS measures the pair distribution function (PDF) with elemental specificity, we will measure if the applied pressure creates anisotropy in the PDF reminiscent of solute segregation along slip bands. By integrating the measured PDFs with our molecular dynamics simulations under analogous conditions, we will explore how different types of slip systems could cause the pressure-dependent segregation. Our study will enhance current knowledge of how solute segregation and local chemical order govern the mechanism of pressure-induced plasticity.