Atomistic simulation of the hydrogen-induced fracture process in an iron-based superalloy
- Sandia National Labs., Livermore, CA (United States)
- Seagate, Bloomington, MN (United States)
Austenitic superalloys exhibit dramatic reductions in ductility and crack growth resistance when high fugacity hydrogen and hydrogen-producing environments trigger a change in fracture mode from microvoid coalescence to slip band and intergranular fracture. Of particular importance is the change to intergranular fracture. We have therefore combined the Embedded Atom Method (EAM) with Monte Carlo simulations and molecular dynamics calculations to help define the effects of hydrogen on segregation and fracture at the atomic level. Nickel was used to simulate the face-centered-cubic austenite lattice while symmetric and asymmetric {sigma}9 tilt boundaries were used to simulate grain boundaries. These simulations show that grain boundaries are strong trap sites for hydrogen. They further show that hydrogen dramatically reduces the bond strength between atoms at grain boundary sites while inhibiting dislocation generation.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 172133
- Report Number(s):
- SAND-95-8549C; CONF-9510273-1; ON: DE96004377
- Resource Relation:
- Conference: Symposium on new techniques for characterizing corrosion and stress corrosion, Cleveland, OH (United States), 29 Oct 1995; Other Information: PBD: [1995]
- Country of Publication:
- United States
- Language:
- English
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