Study of the effect of Ti content on hydrogen embrittlement of Incoloy 903

The microstructure and performance in Incoloy 903 alloys with different Ti contents as hydrogen resistent alloys have been investigated. The results revealed that the experimental IN903 alloy with Ti content of 1.36 wt% exhibits the lowest susceptibility to hydrogen embrittlement with relatively high strength, but higher susceptibilities for alloys with lower and higher Ti contents; the difference in performance of the alloys resulted from varying the Ti content is closely related to the variation in microstructure and deformation characteristics of the alloys. Precipitation of large-size γ' and μ phases both at grain (twin) boundaries and within grains, as well as planar slip, can help the trapping and local accumulation of hydrogen, and thus accelerates the occurrence of hydrogen embrittlement.