Iron‐Carbon Alloy Under Shock Compression: Implications for the Carbon Concentration in Earth’s Inner Core

Huang, Yuqian; Hou, Mingcai; Gan, Bo; Li, Xiaohong; He, Duanwei; Jiang, Gang; Zhang, Youjun; Liu, Yun

doi:10.1029/2021jb023645

Cited by 6 publications

(3 citation statements)

References 81 publications

(162 reference statements)

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“…The V P of Fe 7 C 3 is slightly higher than that of Fe, and both are much larger than the PREM values. Thus, carbon might be ruled out as the major light element in the Earth's inner core, which is consistent with findings of Fe-C phase, [38] Fe-C solid solution, [39] and geochemical [40] investigations. By analyzing the Fe-C phase diagram at high temperatures and pressures, Fei et al suggested that the carbon content of the inner core is about 2.24%.…”

Section: Geophysical Implications For Inner Core Compositionsupporting

confidence: 87%

“…[38] More recently, Huang et al experimentally determined Fe-C solid solution densities up to core pressures, and concluded that interstitial carbon can lower the density of iron and be present in the inner core. [39] Using geochemical methods, McDonough concluded that the carbon content of the inner core is less than 0.2%. [40] Therefore, if carbon is present in the inner core, other light elements must also be present, which has inspired many studies of the Fe-C-Si ternary sys-tem.…”

Section: Geophysical Implications For Inner Core Compositionmentioning

confidence: 99%

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First-principles calculations of high pressure and temperature properties of Fe₇C₃

et al. 2023

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Eckstrom-Adcock iron carbide (Fe7C3) is considered to be the main constituent of the Earth’s inner core, owing to its low shear wave velocity. However, the crystal structure of Fe7C3 remains controversial and its thermoelastic properties are not well constrained at high temperature and pressure conditions. Based on the first-principles simulation method, we calculated the relative phase stability, equation of state, and sound velocity of Fe7C3 at core conditions. The results indicate that the orthorhombic phase of Fe7C3 is stable at core conditions. While Fe7C3 does reproduce the low shear wave velocity and high Poisson’s ratio of the inner core, its compressional wave velocity and density are 12% higher and 6% lower than those observed in seismic data, respectively. Therefore, we argue that carbon alone cannot completely explain the thermal properties of the inner core and the inclusion of other light elements may be required.

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Section: Geophysical Implications For Inner Core Compositionsupporting

confidence: 87%

Section: Geophysical Implications For Inner Core Compositionmentioning

confidence: 99%

First-principles calculations of high pressure and temperature properties of Fe₇C₃

et al. 2023

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“…The equation of state is a functional expression that describes the relationship between the state variables of a substance, and is used to express the properties of a substance under certain thermodynamic conditions [3,4]. The study of the equation of state is the key to understanding the failure mechanism of materials under strong dynamic loads, and it is also the basis for numerical calculation of dynamic responses under extreme dynamic loads such as explosions and ultra-highspeed shocks [5,6].…”

Section: Introductionmentioning

confidence: 99%

Experimental research on impact adiabatic relationship of 30CrMnSiNi2A steel

Yan

Zhang

et al. 2023

J. Phys.: Conf. Ser.

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As an ultra-high strength steel, 30CrMnSiNi2A steel has good plasticity, toughness and fatigue resistance, and it has been widely used in components that withstand explosion and dynamic shock loads. Therefore, the mechanical behavior of 30CrMnSiNi2A steel under strong impact load is the focus of attention. In this paper, the flyer impact experiment of 30CrMnSiNi2A steel is carried out in the pressure range of 0~20 GPa by a one-stage light air gun, and the impact adiabatic relationship of 30CrMnSiNi2A steel is studied. The Hugoniot pressure and Hugoniot temperature of 30CrMnSiNi2A steel were obtained by fitting the valid experimental data. The research results provide a reference for the application of 30CrMnSiNi2A steel in the field of explosion and impact.

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Molecular dynamics simulation of shock waves in Fe and Fe–C: Influence of system characteristics

Thürmer,

Luu,

Merkert

2024

Journal of Applied Physics

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Pressure-induced phase transformation in iron and its alloys is a classic research topic in solid-state physics, material science, and geophysics. The crystal structure of iron undergoes a phase transformation at a hydrostatic pressure of 13 GPa, changing from a body-centered cubic system to a hexagonal close-packed system. Although extensive research has been carried out on the transformation in iron by using molecular dynamics simulations, there is very limited literature that focuses on the contribution of parent phase orientations, system size, and impurities to the phase evolution. In this work, classic molecular dynamics simulations have been employed to investigate the effects of system size, lattice orientation, and impurity concentration on the pressure-induced phase transformation of iron and iron alloys for the first time. Our results show that the lattice orientation has a strong influence on the phase transition behavior, while the influence of carbon is small. The phase transition is slightly delayed with increasing carbon content, whereas the transition pressure increases from [001] to [011] to [111] orientation. The amount of twinning and stacking faults highly depends on the orientation. It is easiest for solitary waves to travel through [111] lattice orientation. The addition of carbon has a slow-down effect on shock velocities, and this effect increases with carbon content and lattice orientation of the samples from [001] to [011] to [111].

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Iron‐Carbon Alloy Under Shock Compression: Implications for the Carbon Concentration in Earth’s Inner Core

Abstract: Seismic and cosmochemical constraints suggest that the Earth's solid inner core primarily consists of an ironnickel (Fe-Ni) alloy with light elements, which are expected to reduce the density by 2.5%-5% with respect to pure iron (

Cited by 6 publications

References 81 publications

First-principles calculations of high pressure and temperature properties of Fe₇C₃

First-principles calculations of high pressure and temperature properties of Fe₇C₃

Experimental research on impact adiabatic relationship of 30CrMnSiNi2A steel

Molecular dynamics simulation of shock waves in Fe and Fe–C: Influence of system characteristics

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Iron‐Carbon Alloy Under Shock Compression: Implications for the Carbon Concentration in Earth’s Inner Core

Abstract: Seismic and cosmochemical constraints suggest that the Earth's solid inner core primarily consists of an ironnickel (Fe-Ni) alloy with light elements, which are expected to reduce the density by 2.5%-5% with respect to pure iron (

Cited by 6 publications

References 81 publications

First-principles calculations of high pressure and temperature properties of Fe7C3

First-principles calculations of high pressure and temperature properties of Fe7C3

Experimental research on impact adiabatic relationship of 30CrMnSiNi2A steel

Molecular dynamics simulation of shock waves in Fe and Fe–C: Influence of system characteristics

Contact Info

Product

Resources

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First-principles calculations of high pressure and temperature properties of Fe₇C₃

First-principles calculations of high pressure and temperature properties of Fe₇C₃