The effects of Ni/Cr on diffusion behavior of Cu in 304 stainless steel

Abstract

The diffusion of Cu in 304 stainless steel controls the formation of Cu precipitation in the bulk of 304 stainless steel. It is influenced by the atoms such as Ni and Cr. The linear synchronous transit/quadratic synchronous transit method was employed to study the effects of alloying elements on Cu diffusion in 304, and the interactions and diffusion of Cu in fcc Fe with Cr or Ni. It is found that Cr slightly repels from vacancy, while Ni and Cu atoms attract the vacancy. The most stable configuration of the solute atom-vacancy is the Ni-vacancy. The migration barrier of Cu is larger in the vicinity of Ni atom, result from stronger Ni-vacancy binding energy. The larger diffusion barrier indicated that the rate of Cu atoms diffusion in 304 is significantly reduced by Ni atoms, while the effect of Cr atoms on diffusion of Cu in 304 is neglectable.