A hydrogen-embrittled niobium sample, fractured above the solvus temperature, has been examined using an ion microprobe. Ion images taken with Nb+, NbH+, H+, and NbO+ ions reveal strong enhancement of the emission of the hydrogen-containing ion species from the walls of the main fracture and from a secondary crack. Comparison of the NbH+/Nb+ ion ratio from the crack walls with that observed from known niobium hydride precipitates demonstrates that the hydrogen-rich phase found on the fracture walls is niobium hydride. The results confirm a postulated mechanism of hydrogen embrittlement by stress-induced precipitation of niobium hydride.
ASJC Scopus subject areas
- Analytical Chemistry