reviewed the manuscript. 3. Determine . 14 as more accurate. The body-centred position is empty. Curves fccliq and bcchcp are extrapolated. c) a rectangle with larger area. Chem. 3.7 Iron has a BCC crystal structure, an atomic radius of 0. - Studylib 56, 172189 (2015). The susceptibility of magnesium at 300 \ K is 1.2 \times 10^{-5} . 2Al(l) + Cr2O3(s) = 2Cr(s) + Al2O3(s), Copyright 2021 Askmemetallurgy.com, All rights reserved. The calculated triple points have the following parameters: liquid is located at 5.2GPa and 1998K, at 7.3GPa and 820K, and liquid at 106.5GPa and 3787K. Most of the previous estimations plot the melting temperature of iron below the melting line obtained from our EoSs (Fig. Why do we calculate the second half of frequencies in DFT? The solution required X mL of a potassium dichromate solution for the oxidation of iron content to the ferric state. (choose either increase, decrease, or no change) Strength _____ Ductility _____ Elastic modulus _____, If 1.5 x 10^{14} boron atoms per cm^3 are added to silicon as a substitutional impurity, determine what fraction of the silicon atoms are displaced in the lattice. B 87, 014405 (2013). d. It becomes one-half as large. CAS A mixture of iron and an unknown material is bombarded with electrons. Based on these data, the adiabatic bulk modulus at the ICB conditions is consistent with isentropes of 7000K and at the ICB with isentropes of 5000K (see Fig. Dewaele, A. et al. The total energy of the crystal is made up of a balance of these two,. The function f() can be written as: The value of the parameter p changes from p=0.4 (for bcc-Fe) to p=0.28 for other Fe polymorphs. You are using a browser version with limited support for CSS. At this temperature, the atomic radii of the iron atom in the two structures are 0.1258 nm and. Thermodynamics and Equations of State of Iron to 350 GPa and - Nature Inter. It was argued that hcp-Fe is likely a stable phase in the inner core of the Earth12,13,14. Calculate the percent change in density from BCC to FCC. If you increase the multiplicity by a factor of 10, how much does the scaled entropy, S/k, change? Lett. The phases of iron at atmospheric pressure are important because of the differences in solubility of carbon, forming different types of steel. BCC BCC structures have no close packed planes. For greater pressures, published data (as of 2007) put the --liquid triple point at pressures that differ by tens of gigapascals and 1000K in the melting point. Mechanic. If the thickness of a uniform wall is doubled, the rate at which heat is conducted through the wall is A. doubled B. increased by a factor of four C. decreased by a factor of four D. cut in half E. unchanged, If the voltage of X-ray tube is doubled, the intensity of X-rays will become: a. Phys. Simple Cubic2. (Simple Explanation), What are Space Groups? The atomic radii of iron atoms at this temperature are 0.126 and 0.129 nm for bcc and fcc, respectively. Yield Stress, Yield Strength, and Yield Point, Elasticity and Youngs Modulus (Theory, Examples, and Table of Values), True Stress-Strain vs Engineering Stress-Strain, Stress, Strain, and the Stress-Strain Curve, What Are Shape Memory Alloys? J. Geophys. 143144, 455467 (2004). What must be the minimum n-region width such that avalanche bra down occurs before the depletion region reaches an ohmic contact (punch-through)? One more important marker for calibration of the Gibbs energy for hcp-Fe and liquid Fe was the liquid triple point14. Many metals such as iron, chromium, tungsten, molybdenum, and vanadium have the BCC crystal structure at room temperature. You can see a useful picture of this in a question posted on Chemistry StackExchange. For example estimations in refs 1 and 18 indicate melting temperatures of 5000K and 5600200K at 330GPa, respectively. Science Lett. 115, B03202 (2010). Thank you for visiting nature.com. (d) is unchanged. Article Res. 5b). The fitted parameters of the EoSs for bcc-Fe, fcc-Fe, hcp-Fe, and liquid iron (Table 1) were obtained by simultaneous optimization of the experimental measurements of the heat capacity, volume and thermal expansion, adiabatic bulk modulus at room pressure, and PVT data (all references are included in the Supplementary Information). The volumes for liquid iron from our EoS and that from ref. Res. 1.231 Its resolving power (a) quadruples. 2-At 912 C, iron changes from the BCC (-Fe) to the FCC (-Fe) structure. Earth Planet. 28, 129141 (1987). Atomic Packing Factor: Fraction of solid sphere volume in a unit cell Sum of sphere volumes of all atoms within a unit cell divided by volume of one unit cell Body-centred cubic (BCC) Atoms located at all 8 corners and 1 atom at the cube centre Chromium (Cr), Iron (Fe-) and tungsten (W) exhibit a bcc structure Where a = cube edge length R . Google Scholar. If the X-ray tube current is reduced to 40 mA, what will be the percent change in the number of Cu K x-rays that are produced by the x-ray. Conductor A has nine times the diameter and nine times the length of conductor B. At higher pressures, the room temperature isotherm6 is consistent with our EoS of hcp-Fe (Supplementary Figure S8). Internat. Answer in Mechanical Engineering for MASOOD HANIF KASU #173485 The DFT calculations in this study enable us to understand how different amounts of H change the unit-cell volume of fcc FeH x alloy and then . Why? Molodets, A., Molodets, M. & Nabatov, S. Helmholtzfree energy of molten metals. Figure 7 - FCC to BCT . B. How can I get that mathematically? The body-centered cubic structure of iron, which is called ferrite, is stable at (i) a temperature of 1,665K (1,392) or above and (ii) at 1,184K (911) or below, Iron crystal structures. strings of text saved by a browser on the user's device. Calculated Gibbs energy of hcp-, fcc-, and liquid Fe at different temperatures at pressure P=125GPa. Accompanying this transformation is a change in the atomic radius of Fefrom R BCC = 0.12584 nm to R FCC = 0.12894 nmand, in addition, a change in density (and volume). Dorogokupets, P. I. P-V-T Equations of state of MgO and thermodynamics. The entropic parameter aS, which characterizes residual entropy of the liquid at 0K is introduced. Mechanical metamaterials made of freestanding quasi-BCC nanolattices of It may look like there are 9 atoms because there are 8 corners and 1 in the center, but actually the cell only intersects portions of those corner atoms. Phase diagram of iron: Implications for the state of the Earths core. If the diameter of a radar dish is doubled, what happens to its resolving power assuming that all other factors remain unchanged? if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[250,250],'msestudent_com-banner-1','ezslot_4',123,'0','0'])};__ez_fad_position('div-gpt-ad-msestudent_com-banner-1-0');If you wanted to describe the face-centered cubic crystal with math, you would describe the cell with the vectors. b) Estimate the, The ratio of the radii of the nuclei _{13}Al^{27} and _{52}Te^{125} is approximately (a) 6:10 (b) 13:52 (c) 40:177 (d) 14:73. A discontinuity in sound velocities of iron at 200GPa may mark the transition of hcp-iron to fcc iron. The calculated triple points at the phase diagram have the following parameters: bcc-fcc-hcp is located at 7.3 GPa and 820 K, bcc-fcc-liquid at 5.2 GPa and 1998 K, and fcc-hcp-liquid . The obtained EoSs allow calculation of PVT relations and thermodynamic properties of Fe at the Earths core conditions (up to 6000K and 350GPa). 55 and 56, pressure was calculated using the NaCl EoS57,58. However, in previous studies, 80 eV He + irradiation induced a series of phase structure changes in single-phase BCC-structured Al-Cr-Fe-Ni HEA due to intense vacancy-mediated atomic diffusion during irradiation, i.e. Geophys. Rhombohedral Close-Packed (Sm-type)6. First Principles Theory of the hcp-fcc Phase Transition in Cobalt - Nature 10 in ref. 408, 155162 (2014). Boehler, R. Temperatures in the Earths core from melting point measurements of iron at high static pressures. The most recent thermodynamic calculations of the Fe phase diagram including solid phases and liquid were performed in a few studies18,19,20,21 using the CALPHAD thermodynamic formalism10,22. At first, the periodic table placed the elements in order of increasing atomic mass. CAS The values of these functions can be found in Tables S1S4. Iron is a major component of the Earths core, therefore knowledge of its PVT relations and thermodynamic properties is extremely important1,2,3,4,5,6. b. 3.6 g/cm^3 to kg/m^3 b. Sokolova, T. S., Dorogokupets, P. I. Rev. At 25 GPa, the unit-cell volume of the fcc phase . The crystal structure is based on the Bravais lattice of the same name, with a single atom at each lattice point on the We're young materials engineers and we want to share our knowledge about materials science on this website! 282, 252257 (2009). Provided by the Springer Nature SharedIt content-sharing initiative. Number of atoms . 2 their data are shown without these corrections). The ratio of density of the crystal before heating and after heating is [atomic weight of F e =56 ]A. Earth Planet. Russ. A comprehensive atomistic investigation on the cascade induced helium Geol. Zhang, J. arXiv:cond-mat/0207318v1 [cond-mat.mtrl-sci] 12 Jul 2002 Slider with three articles shown per slide. Lett. The volume dependence of Gruneisen parameter of sodium has been firstly analyzed. The total volume of the unit cell is just the volume of a cube. You can read all about interstitial sites in this article, but BCC has two types of interstitial sites: octahedral and tetrahedral. Mechanical Engineering. Describing complex Bravais lattice as a simple Bravais lattice with a basis, Implement Seek on /dev/stdin file descriptor in Rust, Linear regulator thermal information missing in datasheet, Follow Up: struct sockaddr storage initialization by network format-string. We store cookies data for a seamless user experience. The melting line of Fe in ref. Figure 5d shows that the calculated P-wave velocity for liquid iron is 5.45.7% lower than PREM and consistent with the calculated estimations84. 41, 2014GL061233 (2014). pause playback. Zeitschrift fur Angewandte Physik 23, 245249 (1967). What Is Magnetic Hysteresis and Why Is It Important? Why do small African island nations perform better than African continental nations, considering democracy and human development? Considering this, find the permeability of annealed iron at saturation. Iron atoms arrange themselves in one of two stable crystal structures called the body-centered cubic structure and the face-centered cubic structure. What is the cutoff, saturation, and active region in a transistor? (b) What is the ratio of the radius of ^{58}\textrm{Ni} to that of ^{528}\textrm{Ha}, one of the largest nuclei ever made? Phys. Rev. CAS Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. At temperatures between 912 degree C and 1394 degree C, the crystal structure changes to FCC. Funamori, N., Yagi, T. & Uchida, T. High-pressure and high-temperature in situ x-ray diffraction study of iron to above 30 GPa using MA8-type apparatus. Res. Look for this article in the future on our website! Solids 54, 221227 (1993). Dewaele, A. et al. At high-pressure conditions, the metastable bcchcp curve is located inside the fcc-Fe or liquid stability field. Many of its properties arise because the next-nearest neighbors bond nearly as powerfully as the nearest neighbors. 8 7 4 g c m 3. Geochem. Stability of the body-centred-cubic phase of iron in the Earths inner core. Tsujino, N. et al. M. N. Magomedov. Funtikov, A. The body-centered cubic lattice is a cube with an atom on each corner and another in the volumetric center of the cube. Determine the total work done, the total heat transfer and show the process on a T-v diagram. As a result, it turns into a) a square with a larger area b) a square with a smaller area c) a rectangle with a larger area d. How many decibels does a chicken produce generally (clucking after laying an egg), and what is the maximum volume that chickens cluck at? 2.6 m/s^2 to km/hr^2 c. 3.5 m^2. What is the density of FCC -iron at 20C? Fig. At high pressures, the present EoS of fcc-Fe averages out the experimental measurements14,17, where pressures were calculated using the EoS of hcp-Fe49. Geophys. Author links open overlay panel Ligong Zhao a 1, Guoxujia Chen a 1, He Zheng a b c, Shuangfeng Jia a, Kaixuan Li a, Renhui Jiang a, Lei Li a, Ying Zhang a, Huayu Peng a, Peili Zhao a, Ziyang Huang a . 1.Introduction. Noting that AL is the volume V of the channel and, Semiconductors can become conductive if their temperature is raised sufficiently to populate the (empty) conduction band from the highest filled levels in the valence band. In ref. Body-Centered Cubic is one of these 14 Bravais lattices and also occurs as a crystal structure. Under isentropic conditions, the entropy at the pressures of the mantlecore boundary (MCB, 135.8GPa) is equal to the entropy at the ICB. Article The authors6 used a third-order BirchMurnaghan EoS to fit the parameters on the room temperature isotherm with a fixed initial density 0=8.2695gcm3 and obtained K0=172.7GPa and K0=4.79. Their triple point liquid is located at 81GPa and 3200K and at 330GPa the melting line is located at 5400K. Another estimation indicates a melting temperature of 6100K at 330GPa21. Phys. D. It is reduced to 1/8th of its original value. Based on another study47, the magnet moment of both fcc-Fe and hcp-Fe approaches zero with increasing temperature and pressure. The carbon concentration in the steel before carburization is 206.5 \ ppm and is initially uniform through the thickness of the. Alfe, D. Temperature of the inner-core boundary of the Earth: Melting of iron at high pressure from first-principles coexistence simulations. 20 are very consistent; however, entropy is consistent only at temperatures close to the melting line (Supplementary Figure S11). Discover crystal lattice structures. J. Geophys. 3) and crosses the melting curve of fcc-Fe at a temperature of 5300K and pressure of 230GPa. Iron (Fe) undergoes an allotropic transformation from a BCC to FCC structure system. What is the percentage volume change upon. The length of the edge of the cubic unit cell is known as the lattice parameter, a. When small pieces of material are assembled into a larger piece, the combined surface area: (a) greatly increases. (1) Here, DFFe!X bcc denotes the free-energy change when 1 out of N Fe atoms is changed to an X atom in a bcc lattice; for an fcc lattice, this quantity is dened analogously. The Acm, where austenite is in equilibrium with cementite + -Fe, is beyond the right edge in Fig. 014101 (2014). Inter. All rights reserved. Some controversial experimental evidence suggests the existence of a fifth high-pressure form that is stable at very high pressures and temperatures.[1]. !Uw "*$nI^a|o9SyS \H X4Nr mj k pxL6 xAUg_{ . 1. Suppose you cut a small gap in a metal ring. Fei, Y. The packing fraction of FCC lattice is 0.74 whereas that of BCC is 0.68. Close. When heated, it transforms from BCC to FCC at 1185 K. The atomic radii of iron atoms at this temperature are 0.126 and 0.129 nm for bcc and fcc, respectively. Its face-centred cubic (FCC) structure allows it to hold a high proportion of carbon in solution. That is, 68% of the volume of the BCC unit cell is occupied by atoms and the remaining 32% is empty space. (Properties, Applications, and Metallurgy), Why Mercury is Used in Thermometers (and Modern Alternatives), Common Examples of Body-Centered Cubic Materials, Body-Centered Cubic Atomic Packing Factor, Interstitial Sites in Body-Centered Cubic. Pure iron goes through a polymorphic change from BCC to FCC upon heating at 912C. Toward an internally consistent pressure scale. J. Geophys. b) a square with smaller area. Annual Rev . In the meantime, to ensure continued support, we are displaying the site without styles How does the number of atoms in a 27.5-gram iron ring compare to the number in a chrome ring of the same mass? It is doubled. Sokolova T. S., Dorogokupets P. I., Dymshits A. M., Danilov B. S. & Litasov K. D. Microsoft excel spreadsheets for calculation of P-V-T relations and thermodynamic properties from equations of state of MgO, diamond and nine metals as pressure markers in high-pressure and high-temperature experiments. Interstitial sites are the spaces inside a crystal where another kind of atom could fit. I have tried using SMTC however this is application specific volume. Body-Centered Cubic4. Hillert, M. & Jarl, M. A model for alloying in ferromagnetic metals. Phys. 6 5 p m.. Phase Equilibria 3, 161165 (1982). The calculated thermodynamic properties (P, T, x=V/V0, , S, CV, CP, KT, KS, th, K, and Gibbs energy, G) for -Fe (bcc-Fe) are listed in Supplementary Table S1 (see also bcc-Fe.xls in the Supplementary Information). The square is heated uniformly. Calculate the percentage of change in volume that occurs when BCC iron is heated and changes to FCC iron. Find the permeability of annealed iron at saturation. (a) Calculate the volume change associated with the change in crystal structure from BCC to FCC if at 912C the BCC unit cell had a lattice constant a = 0.293 nm and the FCC unit cell a lattice constant a'=0.363 nm. & Dewaele, A. Equations of state of MgO, Au, Pt, NaCl-B1, and NaCl-B2: Internally consistent high-temperature pressure scales. For SC, BCC, and FCC crystal structures, the respective values of n are 1, 2, and 4, whereas the expressions for a (since VC = a3) are . Rev. The Body-Centered Cubic (BCC) unit cell can be imagined as a cube with an atom on each corner, and an atom in the cube's center. 1. 99, 42734284 (1994). Show that beta approx 3alpha, by calculating the change in volume DeltaV of a cube with sides of length L. 13.3, The reaction; 2N 2 O 5 greater than 4NO 2 + 02, shows an increase in the concentration of NO 2 by 20 * 10 ? The susceptibility of annealed iron at saturation is 5500. At pressures above approximately 10 GPa and temperatures of a few hundred kelvin or less, -iron changes into a hexagonal close-packed (hcp) structure, which is also known as -iron or hexaferrum;[15] the higher-temperature -phase also changes into -iron, but does so at a higher pressure. Geoscience 94, 162169 (2016). The A2 forms the boundary between the beta iron and alpha fields in the phase diagram in Figure 1. The newly measured melting line of Fe extrapolated to 330GPa reveals a temperature of about 6230500 K14. 25, 297356 (1981). At very high pressure, a fourth form exists, called epsilon iron (-Fe). Effects of Co and Cr on bcc Fe grain boundaries cohesion from first The packing fraction is the ratio of volume taken by actual atoms and the total volume of the cube. a cubic bcc lattice is created without the need to change the volume of the bct cell. The Hexagonal Close-Packed (HCP) crystal structure is one of the most common ways for atoms to arrange themselves in metals. B. inversely proportional. In addition, the magnetic contribution to the Helmholtz free energy was calculated according to ref. Fei, Y., Murphy, C., Shibazaki, Y., Shahar, A. 14. 39, L20308 (2012). Belashchenko, D. K. Estimation of the thermodynamic characteristics of the Earths core using the embedded atom model. B 91, 174105 (2015). The authors declare no competing financial interests. What are Alloys? & Litasov, K. D. Self-consistent pressure scales based on the equations of state for ruby, diamond, MgO, B2-NaCl, as well as Au, Pt and other metals to 4 Mbars and 3000 K. Russ. What is b in terms of R? Phys. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. d. first decreases and then enhances. Silicon atom density is 5 x 10^22 cm^-3. Res. The liquid iron density calculated in our study is 7.68.2% higher than PREM and the calculated one95 is 8.97.7% higher than PREM (Fig. (Metallurgy, How They Work, and Applications), What is the Difference Between Iron, Steel, and Cast Iron? 1. a=b^2; a=2R. Sound velocity of FeS liquids at high pressure: implications for the Moons molten outer core. B. Wide-range multiphase equation of state for iron. What is the change in an e. Is there any peak shift between bulk and nano materials in XRD? d. It becomes one-half as large. Physics of the Solid State What is the fractional volume change in iron as it transforms from. If you werent sure about the difference between crystal structure and Bravais lattice, check out this article. If a distance between two nearest atoms is 3.7 ? Res. The pressure obtained based on the compressional wave sound velocity and density measurements of bcc-Fe61 is also shown in Supplementary Figure S5 for comparison. Transcribed image text: 2. 18) decreases with increase of temperature and pressure up to 1.51.6 at 100GPa and 30004000K (Supplementary Table S2). Both these phenomena and also the methods of preventing the destruction of materials are presented. This work was financially supported by Russian Science Foundation (No 14-17-00601) and performed under program of Ministry of education and science of Russian Federation (Project No 14.B25.31.0032). Anzellini, S., Dewaele, A., Mezouar, M., Loubeyre, P. & Morard, G. Melting of iron at Earths inner core boundary based on fast X-ray diffraction. theoretical grounds. ADS Yamazaki, D. et al. Lett. For a great reference for all crystal structures, check out The AFLOW Library of Crystallographic Prototypes., Single-Element Crystal Structures and the 14 Bravais Lattices. Please briefly explain why you feel this question should be reported. In the book Condensed Matter Physics by Marder I have read that an FCC lattice can be obtained by expanding a bcc lattice along one axis by a factor of $\sqrt{2}$. A given number of atoms occupy slightly . Quasihydrostatic equation of state of iron above 2 Mbar. As opposed to the case of Fe, where the bcc-fcc structural transformation occurs 140 K above the Curie temperature, the fcc-hcp transition in Co takes place far below the Curie temperature ~1400 K 11. How to cite this article: Dorogokupets, P. I. et al. It is halved. Res. (Crystal Structure, Properties, Interstitial Sites, and Examples), What is the Difference Between FCC and HCP? Data 15, 967983 (1986). b. doubles. In order to wake a sleeping child, the volume on an alarm clock is tripled. Campbell, A. J. et al. For pure iron this change occurs at 910 C. The body-centred cubic (bcc) crystals of Figure 2 change to face-centred cubic (fcc) crystals as illustrated in Figure 3. What cause FCC to BCC structure change at steel? - Quora copyright 2003-2023 Homework.Study.com. J. Statist. Aitta, A. Connect and share knowledge within a single location that is structured and easy to search. Calphad 29, 6889 (2005). Swartzendruber, L. The Fe (Iron) System. Dorogokupets, P. I., Dymshits, A. M., Sokolova, T. S., Danilov, B. S. & Litasov, K. D. The equations of state of forsterite, wadsleyite, ringwoodite, akimotoite, MgSiO3-perovskite and postperovskite and phase diagram of the Mg2SiO4 system at pressures to 130 GPa. Delta iron (-Fe) Peculiarly, above 1,394 C (2,541 F) iron changes back into the bcc structure, known as -Fe. This conventional cell has advantages because it is highly symmetric and easy for humans to understand. 36, 157161 (1965). At higher pressure conditions, the metastable bcchcp curve is in the fcc-Fe or liquid stability field. ADS At the standard conditions (T=298.15K and P=1bar), iron is a ferromagnet and has a body-centred cubic (bcc) structure (-Fe or bcc-Fe). [10][11] The maximum solubility of carbon is about 0.02 wt% at 727C (1,341F) and 0.001% at 0C (32F). The Clapeyron slope (T/P)S for hcp-Fe differs significantly for both the liquid Fe and the calculated model95. Phys. 375, 244253 (2013). If the mass of the bob of simple pendulum decreases, its time period will increase or decrease? For a full article explaining APF, check out this link. We've added a "Necessary cookies only" option to the cookie consent popup, FCC lattice as a stack of triangular lattices, Understanding FCC and BCC Bravais Lattices, Structure Factor for a Simple BCC Lattice. 3). Phys. Desai, P. D. Thermodynamic properties of iron and silicon. The atomic mass of Fe is 55.845 gr/mol. W is the prototype for BCC.if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[300,250],'msestudent_com-medrectangle-3','ezslot_6',142,'0','0'])};__ez_fad_position('div-gpt-ad-msestudent_com-medrectangle-3-0'); The Body-Centered Cubic (BCC) unit cell can be imagined as a cube with an atom on each corner, and an atom in the cubes center. (c) reduces by 2. (c) increases by 2. Scientific Reports (Sci Rep) Jacobs, M. H. & Schmid-Fetzer, R. Thermodynamic properties and equation of state of fcc aluminum and bcc iron, derived from a lattice vibrational method. 41, 850864 (2003). (a) Calculate the radius of ^{58}\textrm{Ni}, one of the most tightly bound stable nuclei. FCC iron is more closely packed than BCC suggesting that iron contracts upon changing from BCC to FCC. Res. c. It is unchanged. We applied the new EoS data for all Fe phases to calculate the phase diagram up to 350GPa (Figs 1, 2 and 3). App. Geophys. Earth Planet. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? Dewaele, A. et al. Kuwabara, S. Sound velocity and elastic properties of FeNi and FeNiC liquids at high pressure. 91, 46774684 (1986). Sci Rep 7, 41863 (2017). This may be one reason that most high melting point metals have a BCC structure. The diffusion coefficient of carbon FCC iron is lower than BCC iron because a) the temperature is higher for FCC b) FCC has a higher packing factor c) FCC is more cubic d) Carbon is substitional i 228, 114126 (2014). Google Scholar. This list is not comprehensive, and BCC can also appear as high temperature/pressure phases, in solidified nonmetals, or in alloys. That picture shows two unit cells of the fcc lattice. Klotz, S., Le Godec, Y., Strassle, T. & Stuhr, U. Phys. Which electronic configuration has the lesser energy and the greater number of unpaired spins: (Kr)4d^95s^1 or (Kr)4d^10? J. Appl. The segregation effects of Co and Cr on the bcc Fe 3 [1 1 0] (1 1 1) grain boundary cohesion are investigated based on the Rice-Wang thermodynamics model by the first-principles DMol method within the framework of density functional theory.