Dislocation-climbing bypass over dispersoids with different lattice misfit in creep deformation of FeCrAl oxide dispersion-strengthened alloys

Abstract

The creep strain rate of FeCrAl oxide dispersion-strengthened alloys, as a promising accident-tolerant fuel (ATF) cladding of the light-water reactors, is accelerated in YAlO3 dispersoids by two to three orders of magnitude compared with Y4Zr3O12 dispersoid at 1273 K and even occurs at an applied stress less than threshold stress for dislocation detachment. Two approaches were carried out to interprete new findings and to clarify their mechanism. By optimizing the relaxation of the dislocation line energy at the dispersoid interface, numerical analyses proved the accerelated dislocation-climbing in the YAlO3 dispersoids. The other is a more atomistic approach. The force on the dislocation induced by the stress field around the dispersoid was analyzed in terms of the Peach–Koehler relationship. The accelerated creep strain rate in YAlO3 dispersoids is attributed to a larger force induced by larger lattice misfit with less coherency in YAlO3 dispersoid.