|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Environmentally Assisted Cracking: Theory and Practice
||B-3: Hydrogen Embrittlement in Ni-base Superalloy 718
||Hamza Khalid, Bilal Mansoor
|On-Site Speaker (Planned)
Hydrogen embrittlement in Ni-base superalloy 718 is affected by many variables including its microstructure, hydrogen charging conditions and mechanical loading. Alloy 718 is called a precipitation-hardenable alloy; subjecting it to certain heat treatments results in the formation of precipitates which increase its strength and hardness. The alloy relies on the coherent metastable γ’ and γ” precipitates for strength whereas the incoherent but stable 𝛿-phase inhibits grain growth. Multiple studies in the last few years have shown that these precipitates also increase the alloy’s susceptibility to hydrogen embrittlement.
We here explore how alloy 718 behaves in its different tempers when subjected to a range of hydrogen charging conditions. Since hydrogen can both act to trap dislocations or enhance dislocation mobility, we observe diverging results in hardness and strength based on the alloy’s microstructure. We attempt to explain these results and improve the understanding of interaction of hydrogen with complex microstructures.