Grain Boundary Segregation of Impurities in Metals and Intergranular Brittle Fracture

摘要

Grain boundary segregation in a Ni-Cr steel during temper embrittlement has been examined both by Auger electron analysis and by the analysis of etched residues from intercrystalline fracture surfaces. Auger analysis yields compositions averaged over all phases at the boundary, whereas the etching method used gives changes in ferrite only. An attempt to prevent Sb grain boundary segregation, by first segregating faster-diffusing P, did not greatly affect the embrittlement up to 1000 hours at 450C. There is one result which suggests that P may reduce Sb boundary segregation. This study will be extended to longer embrittling times. (Author)