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The effect of alloying elements on the environmental embrittlement of L12 type intermetallics is summarized. The results show that the ductilizing effect of boron doping in Ni3Al is mainly to suppress the moisture-induced environmental embrittlement. The mechanism of this suppression effect is proved to lie in the fact that it severely reduces the hydrogen diffusivity along the grain boundaries. However, the boron doping in Co3Ti alloys does not have the same effect of suppressing the environmental embrittlement. The different behavior of boron doping in Ni3Al and Co3Ti may be attributed to its different segregation behavior on the grain boundaries. Boron in Co3Ti does not segregate on the grain boundaries and cannot effectively reduce the hydrogen diffusivity along the grain boundaries. The moisture-induced environmental embrittlement of Co3Ti alloy can be completely suppressed by the addition of Fe. As proved by Auger, this suppression effect is due to its obvious reduction of the surface kinetic reac
The results of alloying elements on the environmental embrittlement of L12 type intermetallics is summarized. The results show that the ductilizing effect of boron doping in Ni3Al is mainly to suppress the moisture-induced environmental embrittlement. The mechanism of this suppression effect is proved to lie in the fact that it severely reduces the hydrogen diffusivity along the grain boundaries. the different behavior of boron doping in Ni3Al and Co3Ti may be attributed to its different segregation behavior on the grain boundaries. Boron in Co3Ti does not segregate on the grain boundaries and can not effectively reduce the hydrogen diffusivity along the grain boundaries. The moisture-induced environmental embrittlement of Co3Ti alloys can be completely suppressed by the addition of Fe. As proved by Auger, this suppression effect is due to its obvious reduction of the su rface kinetic reac