Abstract
Precipitation-hardened nickel-based superalloys are some of the best candidates for subsea oil and gas industries due to their excellent mechanical properties and good corrosion resistance. However, these high-strength alloys are susceptible to hydrogen embrittlement-a phenomenon with a detrimental effect on in-service metals leading to unexpected failure-when they are used in a hydrogen-containing environment. In this paper, we studied the hydrogen embrittlement susceptibility of two different heat-treated nickel-based 725 superalloy by using small-scale ex-situ slow strain rate tensile tests and in-situ nanoindentation tests. It was concluded that the existence of grain boundary carbides led to intergranular cracking of Alloy 725 and an early fracture of the alloy with and without hydrogen. The size of strengthening phases γ' and γ'' does not show an obvious effect on the hydrogen susceptibility of Alloy 725.
Original language | English |
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Publication status | Published - Sept 2019 |
Externally published | Yes |