An auger electron spectroscopy (AES) study was performed to characterize grain boundary segregation behavior and grain boundary precipitation occurring during slow strain rate tensile tests (SSRTTs) of alloy K-500. It was discovered that flake-like precipitates formed on grain boundaries of some test alloys which had a high bulk Cu level. Auger electron (AE) spectra taken from precipitates and AE mapping of grain boundary facets containing precipitates indicated that these precipitates were most likely titanium carbides. The grain boundary segregation that existed in as-processed alloys was also changed in the course of SSRTTs. A significant reduction in C segregation and a noticeable increase in Cu segregation were observed in test alloys after SSRTTs. Graphite precipitation was not detected in any of the test alloys before or after SSRTTs. The carbide precipitation and change in segregation pattern are qualitatively understandable on the basis of available thermodynamic data, but further study is necessary to fully explain the observed phenomena.