Precise element distribution analysis across grain boundaries of electron-irradiated stainless steels

Precise element distributions across austenitic stainless steel grain boundaries were investigated by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy. Observed element distributions and TEM electron probe intensity profiles were approximated by one- and two-dimensional Gaussian distributions, respectively. Then, the more precise element distributions should have variances of B-b, and the segregated or depleted element concentrations on grain boundaries should be multiplied by a factor of √(B/(B-b)), where B is the variance of the observed element profile and b is the variance of the probe intensity profile. As sample thickness decreased by ion milling, Cr and Ni concentrations were observed to decrease and increase, respectively, on an identical grain boundary. The corrected element concentrations, however, gave constant values on an identical grain boundary of stainless steels. ((orig.))