The effect of nickel on the strength of iron nickel alloys: Implications for the Earth’s inner core

Journal Article · Mon Aug 06 00:00:00 EDT 2018 · Physics of the Earth and Planetary Interiors

DOI:https://doi.org/10.1016/j.pepi.2018.08.003· OSTI ID:1490885

Reagan, Mary M. ^[1]; Gleason, Arianna E. ^[2]; Liu, Jin ^[1]; Krawczynski, Michael J. ^[3]; Van Orman, James A. ^[4]; Mao, Wendy L. ^[2]

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1. Stanford Univ., Stanford, CA (United States)
2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
3. Washington Univ., St. Louis, MO (United States)
4. Case Western Reserve Univ., Cleveland, OH (United States)

Here, we investigated the effect of nickel on the strength of iron-nickel (FeNi) alloys at high pressure. Using radial X-ray diffraction coupled with literature results from nuclear resonance inelastic X-ray scattering measurements we determined the bulk strength of two FeNi alloys (Fe_0.88Ni_0.12 and Fe_0.8Ni_0.2) at high pressures up to 70 GPa. When extrapolated to Earth’s inner core conditions, the strength of these FeNi alloys is found to increase relative to pure Fe. For the likely composition and conditions of the inner core, we estimate that an FeNi alloy with ~5.5 wt% Ni would have a strength that is ~125% greater than estimates for pure Fe. As shear strength is a measure of a material’s resistance to flow, our results have implications for understanding the deformation processes inside planetary interiors and support dislocation creep as the dominant mechanism in the Earth’s inner core.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC02-76SF00515; AC02-05CH11231; NA0001974; FG02-99ER45775; AC02-06CH11357
• OSTI ID: 1490885
• Alternate ID(s): OSTI ID: 1703294
• Journal Information: Physics of the Earth and Planetary Interiors, Vol. 283, Issue C; ISSN 0031-9201
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
High pressure
Strength
Earth’s inner core
Deformation
FeNi alloy