MAB Phases Research Articles

Discovery of Bimetallic Hexagonal MBene Mo2ErB3T2.5 (T = O, F, and Cl).

Exfoliation from quaternary hexagonal MAB (h-MAB) phases has been suggested as a method for producing 2D in-plane ordered MBenes (i-MBenes) with the general formula (M'2/3M″1/3)2AB2. However, experimental realization of defect-free i-MBenes has not been achieved yet due to the absence of a suitable parent quaternary h-MAB phase. In this study, a machine learning (ML)model is used to predict the stability of 15771 quaternary h-MAB phases generated by considering 33 transition metals for the M site and 16 p-block elements for the A site. Out of these compounds, only 195 are identified as potentially stable. Subsequent high-precision first-principles calculations confirm that 47 of them exhibit both thermodynamic and dynamic stability. Their potential for exfoliation into bimetallic i-MBenes is investigated by bonding analysis. Leveraging these theoretical insights, a bimetallic i-MBene is successfully synthesized, namely 2D Mo2ErB3T2.5 (T = F, Cl and O). Further experimental scrutiny reveals its excellent performance for the hydrogen evolution reaction (HER), highlighting the application potential of bimetallic i-MBenes.

A rising Layered Boride Family for Energy and Catalysis Applications: Novel Hexagonal MAB phases and MBenes.

Over the past decade, conventional MAX phases and MXenes have garnered significant interest, primarily limited to carbides and/or nitrides. However, in 2019, the hexagonal ternary boride Ti2InB2 was successfully synthesized, sparking extensive research into hexagonal MAB (h-MAB) phases and their derived MBenes (h-MBenes). In recent years, h-MAB and h-MBenes have become focal points in the fields of physics, chemistry, and materials science. The unique properties and promising performances of h-MBenes in catalysis, energy storage, spintronics, and electrical devices underscore their considerable potential. Nonetheless, the exploration of h-MAB and h-MBenes is still in its nascent stages, with many anticipated properties and potentials yet to be fully explored. This article introduces the general concepts, crystal structure, and exfoliation properties of h-MAB phases, while also highlighting advancements in the synthesis and applications of h-MBenes. Finally, we discuss future challenges and prospects for the study of h-MAB and h-MBenes.

Structural and Hydrogen Evolution Electrocatalysis Properties of Cr–Al–B MAB Phase Thin Films

Thin‐film materials libraries (MLs) in the system Cr–Al–B are synthesized on 100 mm diameter Al2O3 sapphire substrates by combinatorial co‐sputtering from elemental targets at substrate temperatures of 600 and 700 °C to study phase formation of MAB phases (M = transition metal, A = A‐group element, B = boron). The formation of a mixture of two MAB phases Cr2AlB2 and Cr3AlB4 on the larger part of the ML prepared at 700 °C is observed by X‐ray diffraction and cross‐sectional transmission electron microscopy (TEM). Anisotropic growth of large grains of the MAB phases extending throughout the entire film thickness is revealed. Depending on the composition, the microstructure shows different levels of porosity and grain interlinkage. Imaging in the high‐resolution TEM mode identifies regions with Cr2AlB2, Cr3AlB4, and intermixed Cr2AlB2 and Cr3AlB4 atomic stacking sequences. Additional to the structural properties, electrocatalytic activity toward the alkaline hydrogen evolution reaction is measured. Higher activities are linked to crystalline MAB‐phase areas, further enhanced by increased porosity of the film which enlarges the surface area and the exposure of the active (010) planes.

Isothermal oxidation of bulk dense Fe2AlB2 and Mn2AlB2 phases in 700–1000 °C temperature range

Herein, the isothermal oxidation of Mn2AlB2 and Fe2AlB2 MAB phases in air was studied. When oxidized at 700 °C, the weight gain kinetics for Mn2AlB2 are sub-cubic up to 96 h as a result of the formation of a Mn2-xAlxO3 protective layer. Severe spallation of the oxides formed was observed at 800 °C and 900 °C, limiting its service temperature. The oxidation kinetics at 900 °C, for Fe2AlB2 become sub-parabolic beyond 60 h due to the formation of a passivating Αl4Β2Ο9 with excellent corner adherence. At both 800 °C and 1000 °C, however, the oxidation is rapid and severe. Therefore, both Mn2AlB2 and Fe2AlB2 may be used in practical application up to 700 °C and 900 °C, respectively. As far as we are aware, Fe2AlB2 is the second transition metal boride that is oxidation resistant at 900 °C; the first, MoAlB, is also a MAB phase.

Synthesis and radiation damage tolerance of Mo0.75W0.25AlB solid solution for nuclear fusion reactor applications

MAB phases (M = transition metal, A = aluminium (Al), B = boron (B)), a new family of nano-laminated ternary transition metal borides with an excellent combination of functional and structural properties, are currently being investigated as potential radiation shielding materials in nuclear fusion reactors. Here, we report the fabrication of a solid solution MAB phase Mo0.75W0.25AlB (Mo - molybdenum, W - tungsten), in the form of dense and high purity pellets, synthesised for the first time using a reactive hot-pressing method. The shielding and irradiation damage properties of the material were also evaluated. Monte Carlo N-Particle (MCNP) calculations showed that W doping in the MoAlB phase is likely to enhance the shielding capacity against neutrons and gamma rays of different energies. The experimental damage tolerance of Mo0.75W0.25AlB to silicon ion (Si+) irradiation indicated that this solid solution compound has a high resistance to crack formation and other radiation damage effects compared to that of pure MoAlB. Thermal annealing of the amorphous Mo0.75W0.25AlB layer formed by irradiation showed that the damaged structure easily recrystallizes at high temperatures, completely returning to the virgin state. The results show that this solid solution should be considered as a promising candidate material for radiation shielding components.

Lattice dynamics, Raman and IR vibrations of stable Al/Si‐containing MAB phases: An ab initio and experimental study

AbstractTo comprehensively understand the physical properties of the MAB phases, a systematic exploration into their lattice dynamics, Raman, and infrared vibrations is undertaken for 24 previously screened stable Al/Si‐containing MAB phases with six crystal structures using density functional theory, where Raman experiments on Cr2AlB2 and Mo2AlB2 as well as the previous work confirm the high accuracy of these calculations with an error <5%. With a strong dependence on the atomic mass and chemical bonding, all Raman‐ and infrared‐active modes for these types are identified, including the atomic motion and wavenumbers. Unlike the 222 and 512 phases, the A atoms in the 212, 314, 414, and 416 phases do not participate in Raman vibrations. Moreover, a linear relationship is found between the Raman wavenumbers of the MAB phase and m−1/2, where m is the mass of primary vibrating atoms. Furthermore, the high coefficient of certainty (>0.90) underscores the robust explanatory power of m−1/2 for the vibrational wavenumber.

Phase stability and mechanical property trends for MAB phases by high-throughput ab initio calculations

MAB phases (MABs) are atomically-thin laminates of ceramic/metallic-like layers, having made a breakthrough in the development of 2D materials. Though offering a vast chemical and phase space, relatively few MABs have been synthesised. To guide experiments, we perform high-throughput ab initio screening of MABs that combine group 4–7 transition metals (M); Al, Si, Ga, Ge, or In (A); and boron (B) focusing on their phase stability trends and mechanical properties. Considering the 1:1:1, 2:1:1, 2:1:2, 3:1:2, 3:1:3, and 3:1:4 M:A:B ratios and 10 phase prototypes, synthesisability of a single-phase compound for each elemental combination is estimated through formation energy spectra of competing dynamically stable MABs. Based on the volumetric proximity of energetically-close phases, we identify systems in which volume-changing deformations may facilitate transformation toughening. Subsequently, chemistry- and phase-structure-related trends in the elastic stiffness and ductility are predicted using elastic-constants-based descriptors. The analysis of directional Cauchy pressures and Young's moduli allows comparing mechanical response parallel and normal to M–B/A layers. The suggested promising MABs include Nb3AlB4, Cr2SiB2, Mn2SiB2 or the already synthesised MoAlB.

Prediction of new 212 M2AB2 borides as a promising candidate for future engineering: DFT calculations

The elemental diversity is critical for identifying ternary MAB phases with exceptional properties by tuning bonding types and strength between constitutive atoms. The interactions between M and A atoms significantly impact the physical and chemical properties of MAB phases. M2AB2 (where M = Hf, Zr; A = Ga, Ge) was studied using first-principles density functional theory (DFT). Lattice constants (a, c) and internal coordinates have been found after optimization. The lattice parameters in terms of structure exhibit conformity with findings from earlier research. The electronic band structure (EBS) density of states (DOS) and density of states (DOS) have been determined. According to the band structures and density of states investigation, these compounds are electrical conductors. The elastic constants were computed using the stress-strain method. The computed elastic constants and phonon dispersion patterns support this newly found compound's mechanical and dynamical stability. The isotropic elastic moduli bulk modulus (B), shear modulus (G), Young's modulus (E), Poisson's ratio (v), and Vickers hardness (Hv) have been explored within the framework of the Voigte-Reusse-Hill approximation. Specific heat capacity, Debye temperature, entropy, Helmholtz free energy, and internal energy changes of M2AB2 (where M = Hf, Zr; A = Ga, Ge) compounds were investigated using thermodynamic characteristics. The minimum thermal conductivity (Kmin) and melting temperature (Tm) of the compounds have also been computed to assess whether they are suitable as thermal barrier coating (TBC) materials or for high-temperature applications. These compounds' optical properties have been studied, demonstrating their usefulness as coating materials for reducing solar heat absorption. The examined physical characteristics of M2AB2 (where M = Hf, Zr; A = Ga, Ge) are contrasted with those of comparable 212 and 211 MAB phases.

Thermal stability and decomposition mechanism of Mo2AlB2 in argon atmosphere

Mo2AlB2 is a new and metastable phase in the MAB phase family. The lamellar Mo2AlB2 compound is considered to be an optimal candidate for preparing 2D MoB nanosheets. However, studies have less focused on its thermostability as compared with other MAB phases. In this work, the thermal stability of Mo2AlB2 was studied under Ar atmosphere to understand its limited applications. The results showed that Mo2AlB2 slowly decomposed at above 800 °C, but completely decomposed into MoB and Al at 1100 °C for only 0.5 h. Based on the experimental results and density functional theory calculations, the decomposition mechanism of Mo2AlB2 phase was analyzed.

Synthesis and characterization of a remarkable ternary boride: Mo2NiB2

In this communication, we report the synthesis of predominantly single phase Mo2NiB2 by pressureless reactive sintering. XRD analysis showed the samples were ≥95% pure. Both computational and experimental results showed the structure and space group to be orthorhombic and 71: Immm, respectively. Computational results showed Mo2NiB2 has superior mechanical properties as compared to ternary borides like MoAlB, WAlB and Cr2AlB2. As a representative example, the bulk modulus of Mo2NiB2 is 299.5 GPa, outperforming the range of 209.2–228.2 GPa observed in MAB phases. With experimental hardness of 12.0 ± 1.48 GPa and compressive strength of 2469.5 ± 84.6 MPa, Mo2NiB2 outperformed ternary borides like MoAlB, Fe2AlB2 and Mn2AlB2. Magnetic measurements by vibrating sample magnetometer showed Mo2NiB2 to be diamagnetic with minor ferromagnetism which was attributed to residual Ni in the samples.

Development of machine learning force field for thermal conductivity analysis in MoAlB: Insights into anisotropic heat transfer mechanisms

The MAB phases have garnered significant attention as a new generation high-temperature structural materials due to their outstanding high-temperature mechanical properties, resistance to oxidation at elevated temperatures, low-temperature synthesis, and machining capabilities. The chemically anisotropic bonding within MAB phases leads to unique anisotropic elastic properties, oxidation behavior, and electrical characteristics, posing challenges in understanding the structure-property relationships.To address this challenge, we leveraged recent advances in machine learning force fields based on quantum mechanics methods. Using ab initio molecular dynamics simulations, we constructed a comprehensive dataset and developed an accurate machine learning force field for the Mo–Cr–Al–B system based on deep neural network. We then employed non-equilibrium molecular dynamics simulations to calculate the phonon thermal conductivity of MoAlB, investigating its temperature dependence and anisotropy. Our analysis includes phonon density of states, phonon participation ratio, and spectral heat flux analysis, shedding light on the temperature-dependent anisotropy of phonon thermal conductivity in MoAlB. This work not only provides a reliable force field for large-scale molecular dynamics simulations but also advances our understanding of the composition-structure-performance relationship in MAB phases.

H-MBenes: Promising Two-Dimensional Material Family for Room-Temperature Antiferromagnetic and Hydrogen Evolution Reaction Applications.

Recently, a new class of two-dimensional (2D) hexagonal transition-metal borides (h-MBenes) was discovered through a combination of ab initio predictions and experimental studies. These h-MBenes are derived from ternary hexagonal MAB (h-MAB) phases and have demonstrated promising potential for practical applications. In this study, we conducted first-principles calculations on 15 h-MBenes and identified four antiferromagnetic metals and 11 electrocatalysts for the hydrogen evolution reaction (HER). Notably, the h-MnB material exhibited a remarkable Néel temperature of 340 K and a high magnetic anisotropy energy of 154 μeV/atom. Additionally, the hydrogen adsorption Gibbs free energies (ΔGH*) for h-ZrBO, h-MoBO, and h-Nb2BO2 are close to the ideal value of 0 eV, indicating their potential as electrochemical catalysts for HER. Further investigations revealed that the electronic structure, Néel temperature, and HER activity of the studied h-MBenes can be tuned by applying biaxial strains. These findings suggest that h-MBenes have wide-ranging applicability in areas such as antiferromagnetic spintronics, flexible electronic devices, and electrocatalysis, thereby expanding the potential applications of 2D transition-metal borides.

MAB phase-alumina composite formation via aluminothermic exchange reactions

The formation of MAB phase-alumina composites through aluminothermic exchange reactions using M-element (Fe, Mn, Cr, Mo, W) oxides has been investigated for the MAB phases Fe2AlB2, Mn2AlB2, Cr2AlB2, MoAlB, and WAlB for the first time. With the exception of WAlB, all systems formed MAB phase and alumina as major phases, with binary M-element borides, aluminides and/or oxides as minor phases. An alternative Al ratio (120%) was investigated, which increased conversion to all MAB phases except Fe2AlB2. Exchange reactions using oxides present a potential alternative to synthesis methods using often more expensive pure elements.

Soft Chemistry of Hard Materials: Low-Temperature Pathways to Bulk and Nanostructured Layered Metal Borides.

Conspectus"Synthesis by design" is often considered to be the primary goal of chemists who make molecules and materials. Synthetic chemists usually have in mind a target they want to make, and they want to be able to design a pathway that can get them to that target as quickly and efficiently as possible. Chemists who synthesize refractory solids, which have melting points above 1000 °C and are often chemically inert at these high temperatures, have access to only a small number of synthetic strategies due to the need to overcome solid-state diffusion, which is the rate-limiting step in such reactions. The use of extremely high temperatures to facilitate diffusion among two or more refractory solids, which precedes any chemical reaction that must occur, generally drives the system to form only the product that is the most thermodynamically stable-the global minimum on an energy landscape-for a certain combination of elements. When trying to target a different product in the same system, one generally cannot rely on thermally driven reactions. Lower-temperature reactions that side step this diffusion limitation can succeed where high temperatures fail by providing access to local minima on an energy landscape. These local minima represent metastable phases that are primed for synthesis, but only if an appropriate pathway and set of reactions can be identified. It is therefore important to develop and understand low-temperature, or "soft", chemical reactions in "hard" refractory systems. These reactions allow us to apply the retrosynthetic framework that molecular chemists rely on to systems where chemists have not previously had such control over reactions, reactivities, and metastable product formation.In this Account, we discuss the development of soft chemical reactions of hard materials in the context of a class of layered, refractory metal borides that are precursors to an emerging family of two-dimensional nanomaterials. Layered ternary metal boride phases such as MoAlB have layers of metal borides, which are chemically unreactive, interleaved with layers of aluminum, which are reactive. Some of the interlayer aluminum can be deintercalated at room temperature in dilute aqueous sodium hydroxide, transforming stable MoAlB into destabilized MoAl1-xB. Mild thermal treatment of submicrometer grains of this destabilized MoAl1-xB sample allows it to traverse the energy landscape and crystallize as Mo2AlB2, a metastable compound. Further thermal treatment transforms Mo2AlB2 into a Mo2AlB2-alumina nanolaminate and ultimately mesoporous MoB, all through continued traversing of the energy landscape using mild chemical and thermal treatments. Similar topochemical manipulations, which maintain structure but change composition, are emerging for other MAB phases and are opening the door to new types of metastable compounds and nanostructured materials in traditionally refractory systems.

Fabrication of Cr2AlB2 and Cr4AlB4 MAB Phase Coatings by Magnetron Sputtering and Post-Annealing

Cr2AlB2 and Cr4AlB4 are members of the MAB phases that exhibit unique properties of both metals and ceramics. However, despite these unique characteristics, Cr2AlB2 and Cr4AlB4 phase coatings have not been widely investigated. In this study, Cr2AlB2 and Cr4AlB4 MAB phase coatings were fabricated by magnetron sputtering at room temperature and post-annealing. A composite target, consisting of a phase-pure disc-shaped CrB target overlapped by uniformly dispersed fan-shaped Al slices, was placed parallel to the substrates. The Al content of the coatings was adjusted by altering the areal proportion of the Al slices. MAB phases have crystallized upon post-annealing the as-deposited coatings on Al2O3(0001) substrates in Ar. The phase compositions and morphologies of the crystalline coatings were found to be dependent on the Al content and the annealing temperature. As-deposited coatings with a Cr:Al:B ratio close to 2:1:2 could crystallize as pure and dense Cr2AlB2 phases within the temperature range of 650–800 °C; higher annealing temperatures resulted in the decomposition of Cr2AlB2, while crystallization at lower temperatures was not evident from X-ray diffraction. As-deposited coatings with a Cr:Al:B ratio close to 3:1:3, despite containing a relatively higher Al content than required by the stoichiometry of Cr4AlB4, exhibited insufficient crystallization of Cr4AlB4 with unknown phases below 840 °C. Higher annealing temperatures resulted in the coexistence of Cr4AlB4 and CrB, indicating that achieving phase-pure and well-crystallized Cr4AlB4 coatings proved challenging, possibly due to the inevitable loss of Al during annealing. The configuration of the composite target and the substrates provides a promising strategy for fabricating phase-pure and dense Cr2AlB2 coatings.

Enhancing oxidation resistance of MoAlB based on its anisotropic oxidation mechanism: A theoretical calculation guided experimental investigation

MoAlB is considered the most promising material for oxidation resistance among the MAB phase family. However, the anisotropic oxidation mechanism at the atomic scale has not been fully investigated, which may limit its practical applications. In this work the anisotropic oxidation mechanism of MoAlB was first explored through systematic theoretical calculations, based on which an effective strategy to enhance its oxidation resistance was identified and successfully implemented in the experimental work. The theoretical calculation revealed that the anisotropic oxidation of MoAlB was primarily related to the difference in free energy of surface oxidation reactions due to the degrees of electron interaction localization of O-Al bonding. A series of candidates of various transition metal-doped MoAlB materials were then designed to improve the weaker surface of MoAlB for oxidation resistance enhancement. Among these candidates, Zr-doped MoAlB was selected to further evaluate the effects of doping on the anisotropic oxidation through the electronic structure and Ab initio molecular dynamics (AIMD). Finally, Zr-doped MoAlB was experimentally synthesized to validate the theoretical design. Non-isothermal oxidation kinetics analysis indicated that Zr doping can enhance the oxidation resistance of MoAlB by promoting the formation of a protective oxide scale and increasing the formation activation energy of volatile products, which finally reduced the thickness of the oxidation scale on the surface after isothermal oxidation of the bulk material. This work not only contributes to an in-depth understanding of the oxidation mechanisms in MoAlB but also presents a new approach to enhance its oxidation resistance and other Al containing ceramic materials beyond MAB phases.

On the complex synthesis reaction mechanisms of the MAB phases: High-speed in-situ neutron diffraction and ex-situ X-ray diffraction studies of MoAlB

High-intensity in-situ neutron diffraction was used in this work to characterise the reaction mechanisms of the MAB phase ceramic, MoAlB, synthesised using both standard pressureless sintering in a vacuum furnace and induction-assisted self-propagating high-temperature synthesis (SHS). The high-speed diffractogram capture rate of 0.1–20 Hz (0.05–10 s) allowed the identification of intermediate phases with lifespans of 1–30 s. It was found that MoAlB formed during pressureless sintering through a multi-stage reaction beginning at ∼510 °C with the formation of MoAl12. An SHS reaction occurred at ∼578 °C, producing metastable β-MoB as an intermediate phase, followed by MoAlB and Mo3Al8. MoAlB was also found to be present during two separate temperature windows, initially following the SHS reaction at ∼578 °C, decomposing almost completely by ⁓1020 °C, then re-forming at ⁓1200 °C. For the induction-assisted SHS process, a reaction between the elemental powders at ∼660 °C lead to the primary formation of β-MoB as an intermediate phase, followed by a transition to α-MoB and intercalation with Al, forming MoAlB in ∼3 s from the beginning of the SHS reaction. Neutron diffraction (ND), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used post-reaction to confirm the compositions and analyse the microstructure of samples produced using both methods.

Structural, elastic, electronic, bonding, thermo-mechanical and optical properties of predicted NbAlB MAB phase in comparison to MoAlB: DFT based ab-initio insights

In recent times transition metal ternary borides with layered structure have attracted much attention of the materials science community. In this study, we have used density functional theory (DFT) based first-principles investigation of the physical properties of prospective NbAlB compound for the first time. From the analysis of the cohesive energy and enthalpy of formation, it was found that NbAlB is expected to be chemically stable. The physical properties of NbAlB have been compared and contrasted with those obtained for MoAlB. Both these MAB phases are elastically anisotropic, mechanically stable, machinable and brittle materials. Structural and elastic features reflect the layered features. The estimated hardness of NbAlB is 19.0 GPa comparable to that of MoAlB (20.8 GPa) suggesting that predicted NbAlB is a hard compound and is suitable for heavy duty industrial applications. NbAlB is more machinable than MoAlB. Electronic band structure calculations reveal conventional metallic behavior with the electronic density of states at the Fermi level arising mainly due to the Nb 4d orbitals in NbAlB. The electronic density of states at the Fermi level is significantly higher in NbAlB in comparison to MoAlB, indicating that NbAlB is expected to exhibit higher level of electrical conductivity. Electronic dispersion is highly anisotropic for both MoAlB and NbAlB with substantially large electronic effective masses in the out-of-plane directions. The bonding features have been elucidated via the analysis of the band structure and charge density distribution. Both the compounds have mixed covalent, ionic and metallic bonding characteristics. The Fermi surfaces of MoAlB and NbAlB consists of electron and hole like sheets. The Debye temperatures of MoAlB and NbAlB are comparable. The estimated melting temperature of NbAlB is somewhat lower than that of MoAlB. NbAlB shows excellent reflection characteristics suitable to be used as an efficient solar reflector. NbAlB is also expected to absorb ultraviolet radiation very effectively. Unlike elastic, bonding, and electronic anisotropy, the optical spectra are fairly isotropic for NbAlB with respect to the polarization of the incident electric field.

Effects of Zn and Si on the microstructure evolution of the Cr-Al-B MAB phase contained in the periodic layered structure formed in-situ

The MAB phases gain large attention in today's world because of their combination of metallic and ceramic. In our previous work, the periodic layered structures (PLSs) containing Cr-Al-B MAB phase were formed at the Fe-Cr-B cast steel/molten Al interface. This work reports the preparation method of the new A-site alloyed Cr-Al-B MAB phase through hot-dip aluminizing (HDA) in different Al melts and subsequent thermal diffusion treatment (TDT) of Fe-Cr-B cast steel. It was found that the Zn and Si in the Al melts had great effects on the formation and microstructure evolution of the Cr-Al-B MAB phase formed during HDA and TDT. Both Zn and Si could partially replace the Al atoms in Cr-Al-B MAB phase, leading to forming a solid solution with double A atoms. The Cr-(Al, Zn)-B and Cr-(Al, Si)-B MAB phases were achieved by A-site replacement in Cr-Al-B MAB phase. Meanwhile, Zn thickened the thickness of this MAB phase, while, Si decreased that of the MAB phase. However, when they were dopped simultaneously, Zn atom preferentially replaced Al atom in Cr-Al-B MAB phase with that of the substitution of Si not happening.

DFT-assisting discovery and characterization of a hexagonal MAB-phase V3PB4

A 314-type MAB phase V3PB4 with hexagonal crystal structure is synthesized by self-propagating high temperature combustion synthesis (SHS), with the help of the full first-principles predictions for the phase stability and adiabatic combustion temperature of SHS. Using XRD and TEM, V3PB4 crystallizes in the space group of P6¯m2, with the lattice parameters a = 3.030 Å and c = 9.148 Å, of much interest, well with the predicted one. Furthermore, the electronic structure, chemical bonding, and elastic properties of hex-V3PB4 are predicted by first-principles. No bandgap around Fermi energy indicates its electronic conductor. And the strong covalent bonding is present between the B and V atoms with, significantly, much weaker V-P bond. With the help of the theoretical model of bond stiffness, the significantly high ratio of bond stiffness of weakest bonds to the strongest ones (0.873) of hex-V3PB4 indicates its poor damage tolerance and fracture toughness. The high bond stiffness results in its high moduli in comparison with other MAB phases. As the number of inserted P atoms increases, the engineering elastic modulus decrease, without the price of an increase in density.