Intermetallic Materials Research Articles

Promoting the ordering of L10-FeNi phase via chemical interactions with substrate: A molecular dynamics simulation study

The L10-type FeNi intermetallic phase is an important rare-earth-free magnetic material. However, its fabrication remains challenging. In this paper, we propose a chemical-interaction-enhanced ordering mechanism in vapor deposition processes, which is supported by molecular dynamics deposition simulations. Additionally, we describe guidelines for the fabrication of further ordered intermetallic thin films. Thus, we present not only the fabrication of an L10-type FeNi intermetallic magnet but also guidelines for developing diverse structural and functional layer-ordered intermetallic materials.

Characterizing sliding wear behavior of A1100/AlFe (p) composites produced via repeated fold-forging and annealing

Abstract Aluminum matrix/aluminum-iron intermetallic composite materials pose challenges in plastic processing due to the susceptibility of hard intermetallic compound particles to fracture. This study introduces a novel fabrication method involving pure iron mesh, hot-dip aluminum plating, and solidification. Through ten consecutive folding, forging, and intermediate annealing cycles, aluminum matrix and iron undergo diffusion, leading to the formation of Fe2Al5 and FeAl3 interface reaction layers, as confirmed by X-ray diffraction analysis. Subsequent forging cycles cause the breakage or detachment of Fe2Al5 and FeAl3 particles from the interface, resulting in the formation of large-sized Fe2Al5 and small-sized Fe2Al5 intermetallic particles. FeAl3 intermetallic particles are observed via microscopic examination. These particles can be uniformly dispersed within the aluminum matrix through plastic flow, enabling the successful fabrication of A1100/Fe2Al5 and AlFe3 composite sheets. Furthermore, the study investigates the impact of intermetallic compound content, sliding speed, and forward load on the dry sliding wear of A1100/FeAl composites. It is found that Fe2Al5 and AlFe3 intermetallic compound particles effectively mitigate adhesive wear, plowing, and oxidative wear of the composites. With an AlFe intermetallic compound content of 4.3 wt.%, the volume wear rate remains low under conditions corresponding to PV = 56.652 (equivalent to a normal load of 19.6 kPa and a sliding speed of 2.87 m s−1).

Microstructure and energy release properties of W-Zr-Al energetic structural material fabricated by explosive consolidation

Multi-element intermetallic energetic structural materials (ESMs) as a new typical ESMs characterized by their high heat release properties and strength, which could be applied as reactive fragment, reactive shell and reactive shaped charge. Al-based ESMs had been extensively studied due to their excellent mechanical properties and high energy release characteristics. But, the low density of Al-based ESMs hindered its application. However, the need for higher density and energy release persists. In this work, the nearly fully dense W-Zr-Al ESMs with a molar ratio of 1.9:1:1 was fabricated successfully by explosive consolidation. The density reached 10.12 g/cm3 (97.5 % of the theoretical maximum density). Microstructure of the specimen was characterized by X-ray diffractometer (XRD), optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and transmission electron microscope (TEM). The heat treatment was used to further improve the performance of the specimen and the mechanical properties of quasi-static compression was investigated before and after heat treatment. The reaction activity and process of W-Zr-Al ESMs was discussed by differential scanning calorimetry (DSC). Besides, the impact-induced energy release tests were carried out to evaluate the reactive characteristics of the W-Zr-Al ESMs. The results indicated that high-density, good-strength and high energy release unreacted W-Zr-Al energetic materials were fabricated successfully by explosive consolidation.

The deformation mechanism of low symmetric Ti–Pt intermetallic compounds containing high density of planar defects

Intermetallic compounds typically exhibit limited plastic deformation capacity due to challenges in activating dislocation slip and deformation twinning, coupled with a lack of alternative deformation mechanisms. Ti–Pt alloys are a prevalent type of intermetallic compound utilized in high-temperature shape memory alloys and as materials for energy applications in electric fields. However, they often exhibit poor deformation capability. Here, we prepared a low-symmetry intermetallic phase, Ti4Pt3, which demonstrates significant plastic deformation capability. This phase features a high density of parallel planar defects, resulting in an exceptionally large lattice periodicity perpendicular to these defects. Through in-situ scanning electron microscope compression tests, we observed substantial plastic deformation in this new phase. Analysis of the deformed Ti4Pt3 phase revealed that the dense planar defects create uniformly distributed sites of internal stress concentration, enabling a rapid increase in back stress within crystals. This phenomenon leads to notable lattice rotation and localized order-disorder transitions, both crucial mechanisms facilitating plastic deformation and enhancing deformation capacity. Our research underscores the potential of leveraging structural asymmetry to enable unconventional deformation mechanisms, thereby enhancing the plasticity of intermetallic materials.

Pressure‐Enhanced Superconductivity and Structural Phase Transition in Layered Sn4P3

High pressure provides a unique tuning method depending on structure modulation to explore the structure–property relationship. Herein, the pressure‐induced structural phase transformation and enhanced superconductivity in a layered binary phosphide Sn4P3 are reported. Comprehensive measurements using in situ synchrotron X‐Ray diffraction and Raman spectroscopy reveal a structural phase transition with mild distortion of SnP3 building blocks and interlayer shrinkage under high pressure. This differs from a conventional trigonal SnAs(P)3 to square SnAs(P)4 topotactic transition in SnAs(P)‐based compound. Through this structure reconstruction under high pressure, electron distribution has been reorganized and phonons have softened, facilitating a high superconducting temperature (Tc) value of 7.8 K at 34.9 GPa, which is almost six times higher than its ambient value. The study introduces a new transition route in layered SnAs/SnP‐based intermetallic materials and provides insight into the structural and electronic changes under high pressure for Sn4P3.

Novel Fe-Mo intermetallic composite synthesized via diffusional-displacive mixed-mode transformation

Transition metal-based intermetallic materials are candidates for high-temperature structural applications. However, they are limited by their low fracture toughness at ambient temperature. Given Fe is a low-cost metal with a low environmental impact, it is necessary to design tough Fe-based intermetallic alloys. We report a novel ferrite-Fe2Mo intermetallic synthesized through arc melting and quenching of Fe0.78Mo0.22 alloy. Diffusional-displacive mixed-mode transformation of the parent ferrite phase resulted in the formation of nanocomposite microstructure. Two distinct microstructure morphologies of the product μ phase were observed: (i) allotriomorphic phase formation at the parent ferrite grain boundaries and (ii) formation of basket-weave Widmanstätten structures at the parent grain interior. Electron probe microanalysis (EPMA) revealed Mo partitioning across ∼800 nm wide Widmanstätten laths, establishing that it is a diffusional-displacive mixed-mode transformation. We performed atom probe tomography (APT) investigations to ascertain the nanoscale Mo solute partitioning. Based on the chemistry of the retained parent ferrite, the Mo partitioning temperature was estimated to be ∼865 °C. Mo partitioned Widmanstätten lath formation is clarified using a shear-assisted diffusional transformation model. APT studies further revealed that the composition of the product μ phase corresponds to stoichiometric Fe2Mo. It is an anomaly since stoichiometric Fe2Mo typically corresponds to λ C14 Laves phase. We explain the mechanism of μ phase formation with Fe2Mo stoichiometry. The nanocomposite exhibits a high hardness (HV2) of 7.54 GPa and excellent toughness (evidenced by resistance to indentation cracking).

Atomistic Insights into Impact-Induced Energy Release and Deformation of Core-Shell-Structured Ni/Al Nanoparticle in an Oxygen Environment.

In actual atmospheric environments, Ni/Al composites subjected to high-velocity impact will undergo both intermetallic reaction and oxidative combustion simultaneously, and the coupling of mechanical and multiple chemical processes leads to extremely complex characteristics of energy release. This work employs ReaxFF molecular dynamics simulations to investigate the impact-induced deformation and energy release of a core-shell-structured Ni/Al nanoparticle in an oxygen environment. It was found that Al directly undergoes fragmentation, while Ni experiences plastic deformation, melting, and fragmentation in sequence as the impact velocity increased. This results in the final morphology of the nanoparticles being an ellipsoidal-clad nanoparticle, spherical Ni/Al melt, and debris cloud. Furthermore, these deformation characteristics are strongly related to the material property of the shell, manifested as Ni shell-Al core particle, being more prone to breakage. Interestingly, the dissociation phenomenon of Ni-Al-O clusters during deformation is observed, which is driven by Ni dissociation and Al oxidation. In addition, the energy release is strongly related to the deformation behavior. When the nanoparticle is not completely broken (Ni undergoes plastic deformation and melting), the energy release comes from the oxidative combustion of Al fragments and the intermetallic reaction driven by atomic mixing. When the nanoparticle is completely broken, the energy release mainly comes from the oxidative combustion of the debris cloud. At the same time, the promoting effect of oxygen concentration on the energy release efficiency is examined. These findings can provide atomic insights into the regulation of impact-induced energy release for reactive intermetallic materials.

Premixing degree-dependent reaction mechanisms of premixed Ni/Al nanolaminates under shock loading

Understanding the intermetallic reaction is critical for reactive metal systems, among which Ni/Al nanolaminates have attracted extensive interest. A long-standing open question is how nanostructure such as premixed interlayer affects the reaction process. Here, we employ molecular dynamics simulations to investigate the effects of premixing degree on the shock-induced reaction mechanisms and reactivity for premixed Ni/Al nanolaminates. The multiple exothermic processes are identified, namely, the Ni–Al mixing driven by diffusion, the B2-NiAl crystallization in premixed interlayer, and the grain coarsening driven by grain boundary migration. Intriguingly, it is found that the specific exothermic processes depend strongly on the premixing degree. As the premixing degree increases, the B2-NiAl crystallization and the grain coarsening appear sequentially. The maximum crystallinity and grain size increase linearly and exponentially with premixing degree, respectively. Furthermore, inspired by the differences in exothermic processes, the intrinsic mechanism for the weakening effects of premixed interlayer on reactivity is elucidated. The B2-NiAl crystallization in premixed interlayer decreases the reaction heat and further the final adiabatic temperature, while the appearance of grain coarsening produces additional heat and alleviates the weakening effect. These findings can provide valuable insights into the nanostructure–reactivity relationship for reactive intermetallic materials.

Ru/CeTX (T=Ti, Sc; X=Ge, Si) Intermetallic Catalysts for NH3 Synthesis at Low Temperature (300 °C): Insight into Composition and Related Mechanisms.

AbstractBecause of its current and future intensive use, the synthesis of sustainable ammonia is of major concern. This study focuses on highlighting the mechanistic behaviours of NH3 production from molecular nitrogen and hydrogen on ruthenium materials supported on cerium‐based ternary intermetallics. An interesting activity is reported for Ru/CeTX materials (T=Sc, Ti; X=Si, Ge) with an ammonia production rate around 0.60 mmolNH3 h−1 g−1 at only 300 °C and 1 bar. While the activity at 400 °C appeared attributable to the N≡N cleavage activation, this low‐temperature activity is no longer correlated with this parameter, but rather to the behaviour regarding hydrogen and especially the ability of cerium‐based intermetallic materials to desorb hydrogen from the structure, supporting an associative‐type mechanism.

Self-isolating electrode deposition process using the area-selective MoO2 and MoO3 atomic layer deposition technique

The traditional patterning process for semiconductor devices typically involves multiple steps, including thin film deposition across the entire substrate, selective removal of unwanted regions through lithography and etching, and subsequent isolation. While area-selective deposition process has been employed to eliminate the need for lithography and etching, the isolation step remains essential. In this study, we suggest an innovative approach to achieve “self-isolation electrode formation” using MoO2 and MoO3 as electrode and inter-metallic insulator materials. In a single deposition batch and subsequent post-deposition annealing (PDA) process, deposited MoOx (x: 2∼3) thin films exhibited transformation into highly crystalline MoO2 and MoO3 with low crystallinity, depending on whether they were deposited on TiN or SiO2 surfaces. We conducted comprehensive analyses, including chemical and electrical characterizations, as well as first-principles calculations based on density-functional theory, to elucidate the underlying mechanisms responsible for the differential reduction and crystallization of MoOx thin films. Finally, we successfully demonstrated the formation of self-isolation electrodes within a vertical structure, accomplished through a single-step process involving MoOx deposition and subsequent PDA. This novel approach, built upon advanced area-selective deposition techniques, holds great promise for the development of state-of-the-art semiconductor devices.

DFT simulation to study the physical properties of ternary intermetallic materials ACuSb (A=Ca, Sr, Ba) for solar cell and TBC materials

This study carried out the configurational, bulk, electronic, optical as well as thermodynamic features of ternary materials ACuSb (A = Ca,Sr, Ba) using first-principles DFT-based calculations. The explored lattice constants as well as unit cell volume are very close to hypothetical results which make sure the correctness of the present study. According to the investigated elastic stiffness constants, the studied compounds are mechanically stable as they hold the Born's stability criteria. Utilizing the calculated values of elastic constants the several polycrystalline parameters such as elastic moduli (B, Y, E), machinability index (μm), hardness (HV), Poisson's ratio, Pugh's and isotropic/anisotropic factor of ACuSb (A = Ca,Sr, Ba) have been calculated and discussed in details. Very high machinability indices of these phases ensure their industrial applications. Since the values of Poisson's and Pugh's are ν < 0.26 and B/G < 0.75, therefore the phases ACuSb (A = Ca,Sr, Ba) show brittle manner. The direction-dependent features of these materials are confirmed from the Universal anisotropy factor analysis. Band structure analysis reveals that every compounds exhibit metallic character. Bond population analysis revealed the different covalent and ionic bonding tendencies in these compounds, with apparent differences in the nature of Cu–Sb bonds. Furthermore, the absorption coefficients of BaCuSb ensures its excellent suitability for solar cell applications, as it demonstrated remarkable UV-range absorption capabilities, distinguishing it from the other compounds in this regard. The thermal analysis demonstrated that these compounds exhibit remarkably low thermal conductivity, indicating their appropriate applications in thermal barrier coating (TBC) materials.

Microstructure, Phase Composition, and Mechanical Properties of Intermetallic Ni-Al-Cr Material Produced by Dual-Wire Electron-Beam Additive Manufacturing

Electron-beam additive manufacturing is one of the most promising methods for creating complex metal parts and structures. Additive manufacturing has already gained wide acceptance in the creation of various constructions from aluminum, copper, titanium, and their alloys as well as different classes of steels and other metallic materials. However, there are still many challenges associated with the additive manufacturing and post-production processing of intermetallic alloys. Thus, it is currently an urgent task for research. In this work, heat-resistant intermetallic alloys based on nickel, aluminum, and chromium were produced by dual-wire electron-beam additive manufacturing using commercial NiCr and Al wires. The microstructure, phase composition, and microhardness of the intermetallic billets are strongly dependent on the ratio of NiCr and Al wires, which have been fed during the additive growth of the material (NiCr:Al = 3:1 and NiCr:Al = 1:3). A metal-matrix composite material (Al3Ni-based intermetallide in Al-based matrix) was fabricated using the NiCr:Al = 1:3 ratio of the wires during the deposition. In tension, it fractures in a brittle manner before the plastic deformation starts, and it possesses a high microhardness of 6–10 GPa with a high dispersion of the value (the mean value is 8.7 GPa). This is associated with the complex phase composition of the material and the high fraction of a brittle Al3Ni intermetallic phase. In the material, obtained with the ratio NiCr:Al = 3:1, the ordered Ni3Al(Cr) and disordered Ni3Cr(Al) intermetallides are the dominating phases. Its microhardness turned out to be lower (4.1 GPa) than that in Al + Al3Ni-based composite, but intermetallic Ni3Al-based alloy demonstrates good mechanical properties in a high-temperature deformation regime (650 MPa, more than 10% elongation at 873 K). Microstructural studies, analysis of phase composition, and tensile mechanical properties of additively produced intermetallic materials show the perspective of dual-wire electron-beam additive manufacturing for producing intermetallic compounds for high-temperature applications.

Magnetocaloric effect in the Laves phases RCo2 (R = Er, Ho, Dy, and Tb) in high magnetic fields

The heavy rare-earth-based Laves phases are well-studied intermetallic materials that stand out for their remarkably high magnetocaloric effects, particularly at cryogenic temperatures. In this study, we present the findings of our comprehensive investigation of cobalt Laves phases RCo2 with R standing for erbium, holmium, dysprosium, and terbium. This includes the determination of the magnetocaloric effect by indirect methods using calorimetric and magnetization data. Furthermore, for the first time in these materials, we directly measured the adiabatic temperature change at high magnetic fields up to 20 T. The largest ΔTad value of 17 K, we obtained for ErCo2. Because the order of the transition significantly impacts the efficiency of thermodynamic cycles, we have also focused on determining the transition order in these materials. This was done through the application of established methods and a recently proposed quantitative criterion including the value of the local exponent n. Further, we compare our results with other materials using a straightforward material-based figure of merit - the temperature-averaged entropy change (TEC). Our results demonstrate the great potential of these materials for applications such as for magnetic hydrogen liquefaction.

Temperature Exposure of Single- and Double-Layer Coatings of Inconel 625 Reinforced with Ni3Al Intermetallics

Abstract The customization of metallic alloys offers the possibility of adding functionalities to a material. Customizing alloys with a dispersion of intermetallic compounds obtained by in situ synthesis does not compromise processing and allows for the addition of functionalities to less noble alloys. However, intermetallic materials present important challenges regarding their processability by welding and forming because of low toughness, ductility, and metallurgical stability at high temperatures. Graded multilayer coatings might offer a balanced solution to the aforementioned challenges by taking advantage of a ductile matrix while the fine dispersion of aluminides reinforces hardness and metallurgical stability. This investigation addressed this challenge by processing coatings of Inconel 625 superalloy with in situ formed Ni-Al based intermetallics to increase hardness and high temperature oxidation resistance while maintaining weldability. Powder mixtures of Inconel 625, Ni, and Al elementary powders were processed as single and double-layer coatings. Inconel 625 atomized alloy was modified with a powder mixture containing 75 wt. % Ni and 25 wt. % Al. Each deposited layer had a different amount of the Ni + Al powder mixtures added to the atomized Inconel 625 alloy. The single layer coating was processed with a mixture containing Inconel 625 and 80 wt. % (Ni + Al), while the double-layer coating of the first layer was deposited with the powder mixture Inconel 625 and 20 wt. % (Ni + Al), and the second layer deposited with Inconel 625 and 80 wt. % (Ni+Al). Monel 400 substrates were used for all deposits in the study. Powder mixtures were deposited by Plasma Transferred Arc allowing the in situ synthesis of Ni-Al intermetallics without compromising weldability. For both coatings, microstructural stability was sustained until 900 °C, and at 1,100°C exposure led to some degree of oxidation, but the increased hardness due to nickel aluminides intermetallics in situ formation was sustained.

Plasma powder transferred arc additive manufacturing of ((Fe, Ni)-Al) intermetallic alloy and resulting properties

Intermetallic alloys such as iron aluminides are of increasing interest for high-temperature applications due to their properties. However, their application potential is restricted by their limited machinability with conventional manufacturing methods such as milling. Arc-based additive manufacturing offers an approach to produce these materials to final contour or with very little post-processing. However, the properties of many intermetallic alloys, such as low toughness, require a special manufacturing process. Using a selected iron-nickel-aluminum intermetallic compound as an example, a possible process, including a subsidiary heat treatment, for the arc-based additive manufacturing of materials based on brittle intermetallic materials is presented. This process route could enable the production of structural components. In addition, some basic mechanical properties that can be achieved in a component are shown proportionally. These properties include initial investigations into the wear resistance of this kind of compounds. It is shown that these intermetallic compounds have a superior wear resistance compared to commonly used co-base alloys but have a lower density compared to cobalt-basis alloys.

Corrosion Resistance of Fe-Cr-Al Intermetallic Coatings Obtained by Aluminizing

The growing interest in intermetallic and metal–intermetallic materials and coatings is based on the number of favorable properties they possess, primarily mechanical. However, the lack of data on their corrosion resistance has largely limited their scope of application. In this study, the corrosion destruction mechanisms of coatings formed on substrates made of AISI 321 steel and Aluchrom W (fechralloy) were investigated. The coatings were created by alloying in an aluminum melt followed by diffusion annealing to form the ultimate intermetallic structure. Corrosion resistance was studied under cyclic exposure to a humid marine atmosphere simulator and potentiostatic tests in an aqueous NaCl solution. Corrosion destruction parameters were determined, and mechanisms for each type of coating were revealed. The conducted studies allowed us to determine the electrochemical parameters of the corrosion destruction process and its mechanisms. It was shown that the corrosion rates during potentiostating for coatings on substrates Cr15Al5 and 12Cr18Ni10Ti differed by almost twofold. Two different mechanisms of corrosion are proposed. The first is associated with the formation of Al2O3 and MgO oxide films, which at the initial stage protect only local areas of the coating surface on Cr15Al5. The second is determined by the diffusion of titanium atoms during annealing to the coating surface on a 12Cr18Ni10Ti steel substrate with the formation of TiC carbide at the grain boundaries.

Hierarchical-heterostructured porous intermetallics in nickel-cobalt-aluminum alloys as efficient electrocatalysts for hydrogen evolution

Extensive researches have unequivocally revealed the remarkable potential of hierarchical porous intermetallic materials within the realms of electrocatalysis and energy materials. Nevertheless, the efficient and cost-effective synthesis of such electrocatalysts remains a challenging task, and the atomic-level mechanisms underlying hydrogen evolutions at active catalytic sites are still insufficiently comprehended. Herein, we report a novel synthesis technique for the hierarchical-heterostructured non-noble Ni-Co-Al intermetallics using spark plasma sintering followed by a selective dealloying process. This approach maximizes the electrochemical active surface area, thereby facilitating highly efficient hydrogen evolution reactions with an impressively low overpotential of only 75 mV at a current density of 10 mA cm−2 and a Tafel slope of 54 mV dec−1. Through operando X-ray absorption fine structure and theoretical calculations, the dynamic evolution process during the hydrogen evolution reaction procedure is investigated and the atomic Ni and Co sites are identified as synergistic catalytic sites. These characteristics render this hierarchical-heterostructured porous intermetallics appealing contenders for electrocatalysts utilized in high-performance large-scale hydrogen generation applications.

Boron Enhanced Complex Concentrated Silicides – New pathway for designing and optimizing ultra-high temperature intermetallic composite materials

Refractory Metal Intermetallic Composites and Refractory Complex Concentrated Alloys have been identified as promising candidates for ultra-high-temperature applications that exceed the limits of superalloys. However, designing and developing new materials with the proper density for aerospace applications is a significant challenge. For this reason, new refractory metal-based materials are in continuous development. This study introduces a new class of materials known as Boron-Enhanced Complex Concentrated Silicides (BECCSs). By providing a balance between density and high-temperature performance, these materials with their density-optimized refractory metal silicide-borides have the potential to revolutionize high-temperature applications. Utilizing a quaternary MoNbTaW equiatomic alloy (ρ = 13.73 gcm−3) as a starting point and a computer-aided alloy modeling tool, seven alloy compositions were designed in a multi-step process aimed at lowering the material density. Through the introduction of Ti, Si, and/or B, the microstructure was transformed from a BCC solid solution to a multiphase structure comprised of silicides and borides. The proposed redesign of the alloy led to a significant reduction in density, even to 5.44 gcm−3. All seven alloys were produced by using a laboratory arc melter, and their microstructure and room-temperature mechanical properties were analyzed using SEM, EDS, EBSD, and micro-indentation. The results of structural characterization allowed us to identify specific phase constituents, and it was established that a transition from BCC solid solutions to silicides/borides-based alloys results in a substantial increase in hardness, even above 1600 H V (17 GPa).

Superconducting properties and vortex pinning in intermetallic BaBi3 single crystals: A magnetization study

Hysteresis and magnetic relaxation measurements were performed on single crystals of BaBi3, which is an intermetallic compound exhibiting superconductivity with a critical temperature (Tc) of 5.9 K. The London penetration depth (λ) was determined to be 130 nm, and the coherence length (ξ) was estimated to be 13 nm. The critical current density (Jc) was found remarkably low, measuring 20,000 A/cm2 under self-field conditions at 1.8 K. Analysis of the pinning forces suggests vortex pinning by crystalline defects associated with volume Δk (variations in the Ginzburg-Landau parameter). The relaxation rate follows the Anderson-Kim model, and the pinning energies range from 1600 K at 0.02 T to 500 K at 0.5 T. Our study aims to advance our understanding of the connection between intrinsic superconducting properties and vortex behavior in intermetallic materials characterized by low thermal fluctuations.

Structural and physical properties of YbCu4Ni based heavy fermion compounds

Rare-earth magnetism in the intermetallic materials YbCu4.2Ni0.8 and Yb0.8Lu0.2Cu4Ni was studied by XRD, magnetization, electrical resistivity and heat capacity measurements. The results from the sample YbCu4.2Ni0.8 include a small amount of the monoclinic superstructure of the cubic AuBe5. Therefore, the formation of a cubic AuBe5 solid solution of YbCu5-xNix is negligible, and consequently, it cannot be used to reach a quantum critical point.