An atomistic study of the effects of stress and hydrogen on a dislocation lock in nickel
- Washington State Univ., Pullman, WA (United States). School of Mechanical and Materials Engineering
- Sandia National Labs., Livermore, CA (United States). Materials Reliability Dept.
Even though austenitic alloys are commonly used in a hydrogen environment, hydrogen-induced fracture of these alloys has been reported. Most recently it has been shown that the failure of these alloys in hydrogen is initiated by void formation at slip band intersections. It is the object of this work to investigate the atomistic mechanisms that occur at these slip band intersections in the presence of hydrogen. Specifically it has been suggested that dislocation-dislocation interactions may play a large role in the initiation of voids or cracks. Hirth has summarized the various forms of dislocation interactions, traditionally called Lomer-Cottrell Locks (LCLs), that can occur. Baskes et al. have investigated the effects of stress on a LCL using an Embedded Atom Method (EAM) model for nickel developed previously by Angelo et al. The EAM is a well-established semi-empirical method of atomistic calculation that has been successfully used for over a decade to calculate the energetics and structure of defects in transition metals. The work by Angelo et al. established that the trapping of hydrogen to single dislocations had a maximum energy of ca. 0.1 eV while the trapping to a LCL was significantly greater, {approximately}0.33 eV, thus the authors expect that a LCL could be important in explaining the fracture behavior of a fcc material in a hydrogen environment. Baskes et al. found that under uniaxial stress a LCL in the absence of hydrogen underwent a number of transitions, but it did not dissociate or form a crack nucleus. In this work the authors extend the previous work to include the effects of hydrogen. Specifically they will simulate the experiments of Moody et al. for the case of room temperature exposure of Inconel to 190 atm of hydrogen.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 653957
- Report Number(s):
- SAND-98-8500C; CONF-980202-; ON: DE98052523; TRN: AHC2DT05%%36
- Resource Relation:
- Conference: Annual meeting of the Minerals, Metals and Materials Society (TMS), San Antonio, TX (United States), 15-19 Feb 1998; Other Information: PBD: 19 Mar 1998
- Country of Publication:
- United States
- Language:
- English
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