Effect of stress on self-diffusion in bcc Fe: An atomistic simulation study

The effect of stress on self-diffusion in body-centered cubic Fe has been investigated using a molecular dynamics simulation. The diffusivities under hydrostatic, uniaxial and shear stresses are calculated and analyzed to clarify the governing factors that affect diffusion under these stresses. The diffusivity is retarded by compressive pressures, enhanced by shear stresses, and shows an intermediate behavior under uniaxial stresses. The mechanism for these stress dependencies is discussed in terms of the effect of stress on vacancy formation enthalpy and migration energy.