Phases and Youngs modulus dataset
A useful data for predicting phases and Youngs modulus using machine learning
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A useful data for predicting phases and Youngs modulus using machine learning
The Young modulus and the Poisson coefficient of two-dimensionally extended columnar graphene are theoretically studied in the uniaxial tension. The effect of length and diameter of nanotubes constituting the composite is considered. The numerical experiments are implemented using the minimum structural link and the periodical boundary conditions via the density functional theory method. The Young moduli of the composite are evaluated upon its extension along the normal to the graphene and along the graphene directions with increasing lengths of carbon nanotubes (CNTs) in the composite. The Poisson coefficient for this type of composites is found to be 0.025.
Despite the importance of single-crystal elastic constants of β-phase titanium alloys in understanding their low Young's modulus—a property crucial for many applications, such data are often difficult to obtain when the alloy composition is close to the instability limit of the β phase, where the presence of α' martensite precludes the fabrication of β-phase single crystal. In the present study, we extracted the single-crystal elastic constants of such a β-phase titanium alloy with low Young's modulus, Ti-36Nb-5Zr (wt. %), from polycrystalline specimens by using an in-situ synchrotron X-ray diffraction technique. It is indicated that the low Young's modulus of the alloy originates from the anomalously low shear modulus C{sub 44} as well as the low shear modulus C′, which is different from a common viewpoint that the Young's modulus of β-phase titanium alloys is dominantly controlled by the C′. This suggests that low C{sub 44} is an important contributor to low Young's modulus for instable β-phase titanium alloys.
Our paper reports a diameter-independent Young’s modulus of 91.9 ± 8.2 GPa for [111] Germanium nanowires (Ge NWs). When the surface oxide layer is accounted for using a core-shell NW approximation, the YM of the Ge core approaches a near theoretical value of 147.6 ± 23.4 GPa. The ultimate strength of a NW device was measured at 10.9 GPa, which represents a very high experimental-to-theoretical strength ratio of ~75%. Furthermore, with increasing interest in this material system as a high-capacity lithium-ion battery anode, the presented data provide inputs that are essential in predicting its lithiation-induced stress fields and fracture behavior.
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Titanium alloys are great implant materials due to their mechanical properties and biocompatibility. However, a large difference in Young’s modulus between bone (~10–40 GPa) and common implant mate-rials (ie. Ti-6Al-4V alloy ~ 110 GPa) leads to stress shielding and possible implant failure. Here, the present work predicts the single crystal elastic stiffness coefficients (c ij ’s) for five binary systems with the body centered cubic lattice of Ti-X (X = Mo, Nb, Ta, Zr, Sn) using first-principles calculations based on Density Functional Theory. In addition, the polycrystalline aggregate properties of bulk modulus, shear modulus, Young’s modulus, and Poisson ratio are calculated. It is shown that the lower Young’s modulus of these Ti-alloys stems from the unstable bcc Ti with a negative value of (c 11 –c 12 ). The data gathered from these efforts are compared with available experimental and other first-principles results in the literature, which set a foundation to design biocompatible Ti alloys for desired elastic properties.
The structural, thermodynamic, elastic, anisotropic and electronic properties of P222{sub 1}-Si have been studied using first-principles calculations. The elastic constants are satisfied with mechanical stability criteria. The mechanical anisotropy is predicted by anisotropic constants Poisson's ratio, shear modulus, Young's modulus and three dimensional curved surface of Young's modulus. These results show that P222{sub 1}-Si and Si–Ge alloys are anisotropic. The sound velocities in different directions and Debye temperature for P222{sub 1}-Si and Si–Ge alloys are also predicted. Electronic structure study shows that P222{sub 1}-Si is an indirect semiconductor with band gap of 0.90 eV. In addition, the band structures of Si–Ge alloys are investigated in this paper. Finally, we also calculate the thermodynamics properties and obtained the relationships between thermal parameters and temperature. - Graphical abstract: Crystal structure and band structure of P222{sub 1}-Si. - Highlights: • A novel P222{sub 1} phase of Si and Si–Ge alloys are proposed. • The mechanical, electronic, and thermodynamic properties of P222{sub 1}-Si are calculated. • The anisotropy of mechanical properties of P222{sub 1}-Si and Si–Ge alloys are discussed.
Young’s modulus is an important parameter for characterizing the strength of, and wave propagation through, a given material. This study improves the estimation of Young’s modulus using the impulse excitation technique based on an experimental analysis of 19 borosilicate glass bars. Analysis of the frequency equations relating Young’s modulus to the out-of-plane and in-plane flexural resonant frequencies of rectangular prisms has been conducted for both the fundamental frequency and its overtones at higher orders of vibration. Furthermore, the Young’s moduli of three novaculite rocks with various porosities were then measured up to the seventh order of vibration to validate the optimum shear constant equation for estimating Young’s modulus. Young’s modulus was found to be nearly frequency independent for these rock samples.
We report first-principles study of structural, electronic, vibrational, dielectric, and elastic properties of Ba₂YTaO₆, a pinning material in high temperature superconductors (HTS), by using density functional theory. By using different exchange-correlation potentials, the accuracy of the calculated lattice constants of Ba₂YTaO₆ has been achieved with GGA-RPBE, since many important physical quantities crucially depend on change in volume. We have calculated the electronic band structure dispersion, total and partial density of states to study the band gap origin and found that Ba₂YTaO₆ is an insulator with a direct band gap of 3.50 eV. From Mulliken population and charge density studies, we conclude that Ba₂YTaO₆ have a mixed ionic-covalent character. Moreover, the vibrational properties, born effective charges, and the dielectric permittivity tensor have been calculated using linear response method. Vibrational spectrum determined through our calculations agrees well with the observed Raman spectrum, and allows assignment of symmetry labels to modes. We perform a detailed analysis of the contribution of the various infrared-active modes to the static dielectric constant to explain its anisotropy, while electronic dielectric tensor of Ba₂YTaO₆ is nearly isotropic, and found that static dielectric constant is in good agreement with experimental value. The six independent elastic constants were calculated and found that tetragonal Ba₂YTaO₆ is mechanically stable. Other elastic properties, including bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and elastic anisotropy ratios are also investigated and found that Poisson's ratio and Young's modulus of Ba₂YTaO₆ are similar to that of other pinning materials in HTS.
To develop a new braze to replace the current state-of-the-art Ag-CuO reactive air braze (RAB), two approaches were proposed: 1) development of a new, self-passivating, silver-free braze and 2) development of a CuO-free, silver-based braze. For the first approach, an integrated computational-experimental method was used. Thermo-Calc® was utilized to quickly screen through hundreds of alloy systems to identify candidate braze compositions with the appropriate melting ranges. Material compositions, melting ranges, mechanical properties, oxidation resistance, and wetting characteristics of the candidate alloys were then analyzed experimentally. Substrate surface pre-treatments, active element additions, and novel brazing schemes were also investigated. Unfortunately, the current study failed to identify new silver-free braze compositions suitable for SOFC applications. To help measure the passivation characteristics of surface passivating braze oxide coatings, work was conducted to demonstrate, for the first time, that a variety of disparate and technologically-relevant thermal, mechanical, and electrochemical oxygen-exchange thin film material properties could all be obtained from in situ , current-collector-free wafer curvature measurements. Specifically, temperature or oxygen partial pressure induced changes in the curvature of 230 nm thick (100)-oriented Pr 0.1 Ce 0.9 O 1.95_x (10PCO) films atop 200 mm thick single crystal yttria stabilized zirconia or magnesium oxide substrates were used to measure the biaxial modulus, Young’s modulus, thermal expansion coefficient, thermochemical expansion coefficient, oxygen nonstoichiometry, chemical oxygen surface exchange coefficient, oxygen surface exchange resistance, thermal stress, chemical stress, thermal strain, and chemical strain of the model mixed ionic electronic conducting material 10PCO. The (100)-oriented thin film 10PCO thermal expansion coefficient, thermo-chemical expansion coefficient, oxygen nonstoichiometry, and Young’s modulus (which is essentially constant, at ~200 MPa, over the entire 280–700 °C temperature range in air) measured here were similar to those from other bulk and thin film 10PCO studies. In addition, the measured PCO10 oxygen surface coefficients were in agreement with those reported by other in situ , current collector- free techniques. However, the measured PCO10 oxygen surface exchange coefficients were significantly lower than those obtained from literature studies with large amounts of intentional or inadvertent precious metal surface coverage/contamination (suggesting that uncontaminated (100)-oriented 10PCO may not be a desirable SOFC cathode material). Taken together, this highlighted the advantages of using a sample’s mechanical response, instead of the more traditional electrical response, to probe the electrochemical properties of the ion-exchange materials used in solid oxide fuel cell, solid oxide electrolysis cell, gas-sensing, battery, emission control, water splitting, water purification, and other electrochemically-active devices. For the second approach, a novel silver-nickel brazing method was developed. It was demonstrated that transient porous nickel interlayers, instead of reactive element additions, could be used to promote Ag wetting on yttria stabilized zirconia (YSZ) and produce high-quality YSZ stainless steel (SS) braze joints. Mechanical tests on these reactive-element-free, silver-based SOFC braze joints, both before and after 500 hours of 750°C oxidation in air, showed that the braze and braze interface strength were higher than the underlying YSZ|NiO-YSZ substrate. The microstructural and compositional evolution of SS|Ag-Ni|YSZ braze joints exposed to dual atmosphere (air on one side and 4%H 2 -96%N 2 on the other side) for 300 hours of isothermal 750 °C aging and 300 25°C/min 35-830 °C rapid thermal cycles were compared to a Ag-3CuO braze joint. In contrast to conventional Ag-CuO RAB brazes, the Ag-Ni brazes remained pore free and well bonded, suggesting that Ag-Ni brazes may be more suitable for long term SOFC operation than Ag-CuO brazes. Other applications inspired by the silver-nickel wetting process on various ceramic substrates were also explored. In support of efforts to identify new CuO-free Ag-based brazes, density functional theory and ab initio molecular dynamics calculations were performed to 1) understand silver wetting on YSZ, and 2) identify new oxides to promote silver wetting on YSZ. These simulations found that while the formation of dissolved oxygen clusters within molten silver at the YSZ interface promoted wetting, much greater wetting angle reductions came from the formation of metal oxide interlayers at the Ag-YSZ interface. Through the development of a simple descriptor, many simple metal oxides (single cation) were examined. Unfortunately, their ability to promote Ag wetting were less than that of CuO. However, expanding the search to multi-cation oxides led to several promising candidates, such as CuAlO 2 , CuGaO 2 , and Cu 3 TiO 4 ; all of which are also stable in the reducing SOFC conditions. Depending upon their solubility in molten Ag, these newly-identified oxides could either be pre-applied as wetting promoting interlayers or directly incorporated into Ag to form new reactive air brazes.
The first principles calculation within the full potential linearized augmented plane wave (FP-LAPW) method is applied to study the structural, electronic and elastic properties of cubic perovskite-type compounds KCaF{sub 3} and RbCaF{sub 3}. The exchange correlation effects are included through the LDA, GGA and modified Becke-Johnson (mBJ) exchange potential. The calculated structural properties such as equilibrium lattice constant, the bulk modulus and its pressure derivative are in good agreement with the available data. KCaF{sub 3} and RbCaF{sub 3} have wide and indirect band gaps and they agree with experimental values. The elastic properties such as elastic constants, anisotropy factor, shear modulus, Young’s modulus and Poisson’s ratio are obtained for the first time. KCaF{sub 3} and RbCaF{sub 3} are elastically anisotropic and the B/G ratio indicate that these are ductile materials.
The magnetic, mechanical, and electronic properties of RhH{sub x} (x = 0, 0.25, 0.75, 1) have been investigated by first-principles calculations based on density functional theory. It is shown that RhH{sub x} (x = 0.25, 0.75, 1) in the cubic structure are magnetic except for Rh. The total magnetic moments of RhH{sub x} (x = 0.25, 0.75, 1) decrease with increasing content of H, which mainly results from the change of the Rh moments. The calculated elastic constants indicate that RhH{sub x} (x = 0, 0.25, 0.75, 1) in the cubic structure are mechanically stable. With increasing H content, the bulk modulus, shear modulus, and Young modulus gradually decrease except the bulk modulus of RhH. By means of the values of the B/G ratio, it is concluded that H doping improves the ductile properties of Rh. The strong hybridization between H-s and Rh-d is the origin of magnetism for RhH{sub x} (x = 0.25, 0.75, 1) and decreases with increasing H content.
In this paper, the structural, elastic, and electronic properties of RIn₃ and RSn₃ (R = Sm, Eu, Gd) compounds have been investigated using the full potential linearized augmented plane wave plus local orbital method within the density functional theory. The structural properties are investigated using the LDA, GGA, and the band correlated LDA+U and GGA+U schemes. The lattice parameters are in good agreement with the available experimental results and the divalent state of Eu is also verified. The spin-orbit coupling is included in order to predict the correct electronic properties and splitting of 4f states of the rare earth elements is also incorporated. We calculated Bulk modulus, shear modulus, Young's modulus, anisotropic ratio, Kleinman parameters, Poisson's ratio, Lame's co-efficient, sound velocities for shear and longitudinal waves, and Debye temperature. We also predict the Cauchy pressure and B/G ratio in order to explore the ductile and brittle behaviors of these compounds.
First principles calculations for the structural, electronic, elastic and phonon properties of the cubic quaternary heusler alloy CuCoMnGa on pressure have been reported by density functional theory (DFT) within generalized gradient approximation (GGA). The calculated values of the elastic constants were used for estimations of the Debye temperatures, the bulk modulus, the shear modulus, the young modulus E, the poisson's ratio σ and the B/G ratio. The elastic constants satisfy all of the mechanical stability criteria. The electronic structures of the ferromagnetic configuration for CuCoMnGa have a metallic character. The estimated magnetic moment per formula unit is 3.76 μ{sub B}. The phonon dispersion is studied using the supercell approach, and the stable nature at 0.2 GPa pressure is observed.
The structural, elastic, thermodynamic, magnetic, and electronic properties of strontium-filled skutterudite component SrFe{sub 4}Sb{sub 12} using the full potential-linear muffin-tin orbital (FP-LMTO) calculation were studied. The local density approximation (LDA) and local spin density approximation (LSDA) for predicting the physical properties were used. The internal parameters used to calculate the ground state properties such as lattice constant, bulk modulus, and its derivative pressure were optimized. Then, we have deduced the elastic constants, shear modulus G, Young modulus E, Poisson’s ratio ν, anisotropic parameter A, ratio B/G, and the Debye temperature (𝜃{sub D}). The quasi-harmonic Debye model as implemented in the Gibbs program is applied to determine the thermal properties such as the Debye temperature (𝜃{sub D}), heat capacity C{sub v} and C{sub p}, thermal expansion coefficient α Helmholtz free energy (A), Gibbs free energy (G), entropy (S) and internal energy (U) at different pressures and temperatures.
Highlights: • Effect of interfacial reaction on Young’s modulus of CNT/Al composite was quantitatively revealed. • Both qualitative and quantitative characterizations of CNT/Al interfacial reaction were conducted. • Volume expansion induced by CNTs-Al{sub 4}C{sub 3} transformation was the key to modulus increase with greater reaction degree. • The significant role of raw CNTs quality in “Young’s modulus-interfacial reaction” relationship was uncovered. - Abstract: 1.5 wt% CNT/Al nanocomposite with limited, moderate and severe interfacial reaction were prepared by flake PM and annealing to study the effect of interfacial reaction on Young's modulus. Both qualitative and quantitative characterizations of CNT/Al interfacial reaction were conducted through TEM observation and electrochemical dissolution. The results showed that the strong reinforcing effect of reaction-formed Al{sub 4}C{sub 3} and the significant volume expansion effect during CNTs-Al{sub 4}C{sub 3} transformation resulted in Young's modulus increase with greater CNT/Al interfacial reaction degree. The significant role of raw CNTs quality in “Young's modulus-interfacial reaction degree” relationship was discussed. Both raw CNT quality and CNT/Al interfacial reaction need to be well controlled and optimized for fabricating CNT/Al nanocomposite with higher Young's modulus.
Identifying the properties of the region where the cement paste meets the aggregate surface (interfacial transition zone, ITZ) is critical to understanding the strength and fracture behavior of carbon nanofiber (CNF) reinforced cement concrete. In this study, the finite element method is employed to investigate the effect of the ITZ on the Young's modulus of cement concrete made with CNF. The numerical models for cement concrete with and without CNF are constructed based on the digital image processing technique. To consider the interface effect, the concept of ''effective aggregate'' is put forward, namely, the Young's modulus and Poisson's ratio for each aggregate particle are replaced by an effective Young's modulus and effective Poisson's ratio, in which the effect of thickness and the Young's modulus of ITZ is taken into account in an averaged manner. Then, the quantitative nanomechanical mapping (based on atomic force microscopy) technique is adopted to measure the Young's modulus and thickness of ITZ with and without CNFs, which are further used as the input parameters in the numerical model. The numerical simulation results are verified by experimental testing, which indicates that the ITZ effect should be considered when implementing the numerical simulation. In addition, this analysis shows that compared with the plain cement concrete, CNFs can greatly enhance the mechanical properties of ITZ, which will in turn improve the Young's modulus of cement concrete significantly. Finally, the effect of thickness and Young's modulus of ITZ on the Young's modulus of CNF reinforced cement concrete is also discussed.