Analysis of Contaminants on Grain-Boundary Fractures
Cracks, with no other damage, were observed in a niobium alloy (Nb-106) part when it was pulled from several months of protective storage for assembly into a rocket nozzle. SEM views showed the cracks to be intergranular, with contaminant particles on a large number of the grain facets. EDX analysis showed they consisted of niobium and fluorine. Plastic replicas, prepared by standard TEM techniques, were analyzed with selected-area electron diffraction, showing a pattern match for niobium tetrafluoride. Auger analyses showed electron spectra containing peaks representing carbon, oxygen, nitrogen, fluorine, and chlorine. Investigation into the processing history of the part...
Analysis of Contaminants on Grain-Boundary Fractures, ASM Failure Analysis Case Histories: Processing Errors and Defects, ASM International, 2019, https://doi.org/10.31399/asm.fach.process.c0045918
Download citation file: