Range Of Alloy Compositions Research Articles

Edge dislocations, alloy composition, and grain boundaries effects on the mechanical properties in NiCo binary alloy

In this research, we investigated the mechanical properties of NiCo binary alloy both with and without grain boundaries, across various alloy compositions. We investigated the effects of edge dislocation, alloy compositions, and grain boundaries on the mechanical properties of FCC NiCo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NiCo$$\\end{document} using molecular dynamics (MD) simulations. By analyzing the influence of the grain boundaries with different alloy compositions on several mechanical properties, we were able to gain a deeper understanding of how these characteristics were modified. The elastic moduli increased with increasing grain boundaries for a specific chemical composition, indicating that NiCo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NiCo$$\\end{document} becomes more rigid. The anisotropy factor analysis showed that NiCo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NiCo$$\\end{document} have a natural tendency toward anisotropy, which is further influenced by the presence of grain boundaries. Grain boundaries have a significant effect on strength and ductility across a wide range of alloy compositions. These results indicate that a deeper comprehension of these implications can aid in designing improved binary alloy with superior mechanical characteristics.

Experimental Investigation of the Influence of Phase Compounds on the Friability of Fe-Si-Mn-Al Complex Alloy

The research presented in the article is devoted to the study of the influence of phase compounds on the friability of the Fe-Si-Mn-Al complex alloy. The urgency of the problem lies in the development of technology for producing a non-scatterable alloy from manganese-containing ores and high-ash coals. The main goal of this work is to determine the range of alloy compositions and the resulting phases that affect the dispersibility of the alloy, which is critically important for its industrial implementation. Research methods include thermodynamic diagram analysis (TDA) using data on the standard enthalpy of formation of intermetallic compounds, as well as experimental tests in an ore-thermal electric furnace with a capacity of 200 kV*A. The results show that Fe-Si-Mn-Al complex alloys form a variety of silicide and aluminide phases, including intermetallic compounds and ternary systems, which is critical for understanding and controlling their physicochemical properties. When melting a complex alloy, the content of leboite (Fe3Si7) in the Fe-Si-Mn-Al system plays a significant role. The development of melting process technology will be aimed at avoiding the FeSi2-Fe3Si7-F2(FeAl3Si2)-Mn11Si19 tetrahedron area. This approach to controlling the composition of a complex alloy is critical to ensuring its consistent friability properties in industrial applications. Thus, this work represents an important step in understanding the physical properties and stability of Fe-Si-Mn-Al complex alloys, which have potential for widespread use in metallurgical and other industrial applications.

High temperature oxidation behavior of Mo-Zr alloys in pure oxygen condition

In the current study, alloys of Mo-95Zr, Mo-80Zr, Mo-50Zr, Mo-35Zr, Mo-20Zr and Mo-3Zr (at. %) were prepared to investigate the microstructure and oxidation behaviors of the whole composition range of Mo-Zr as-cast alloys. Laves, (Zr) and/or (Mo) intermetallic phases were presented in the primary dendrite, eutectic or peritectic structures in the prepared alloys. The isothermal oxidation process was accompanied by the formation of multi-layer, consisting of the porous and loose ZrO2 and MoO3, which was individually changed from the (Zr), Laves and (Mo). The specimens were examined using a combination of gravimetry and several surface-analytical techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and electron microprobe. Phases composition on the microstructure and oxidation behavior, and the sources of internal stress and defects formation in oxide layer on these alloys during oxidation have been discussed.

Combinatorial processing and evaluation of the phase evolution and oxidation behavior of Hf-Al-Si refractory complex concentrated alloys

Refractory complex concentrated alloys (RCCAs) are a unique group of materials defined by the shared principality between all alloying elements and the tailorable properties at high temperatures (>1000 °C). RCCA systems can be optimized using high-throughput processing which allows for simultaneous characterization and testing over a range of compositions. A compositionally-graded Hf-Al-Si coating was compositionally mapped using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) to identify relative compositions as a function of position on the wafer. High temperature CALPHAD phase diagrams and thermodynamic predictions for a Hf50Al50-xSix alloy and its (Hf50Al50-xSix)1-yOy oxide were coupled with experimental results. The RCCA wafer was heat treated at 1200 °C to observe any phase changes and oxidation behavior at elevated temperatures. Characterization of the RCCA was performed before and after heating using synchrotron radiation X-ray diffraction (SR-XRD) to identify the phases and oxidation states as a function of the compositional gradient and to determine an alloy composition range with the least oxidation. SR-XRD pre- and post-treating revealed an inherent amorphous Hf20Al7Si13 phase across the as-deposited coating, similarities in spectra pre- and post-treating for compositions containing less Hf and more Al and Si relative to the entire gradient film, and the presence of significant HfO2 and Al6Si2O13 oxide for compositions consisting of more Hf and less Al and Si relative to the entire gradient film. The SR-XRD and CALPHAD modeling suggests that compositions of 31–48 at.% Hf, 21–48 at.% Al, and 9–27 at.% Si display the greatest resistance to detrimental oxidation upon heating to 1200 ∘C.

Customized design of amorphous solids by generative deep learning

<p>The design of advanced amorphous solids, such as metallic glasses, with targeted properties through artificial intelligence signifies a paradigmatic shift in physical metallurgy and materials technology. Here, we developed a machine learning architecture that facilitates the generation of metallic glasses with targeted multifunctional properties. Our architecture integrates the state-of-the-art unsupervised generative adversarial network model with supervised models, allowing the incorporation of general prior knowledge, derived from thousands of data points across a vast range of alloy compositions, into the creation of data points for a specific type of composition, which overcame the common issue of data scarcity typically encountered in the design of a given type of metallic glasses. Using our generative model, we have successfully designed copper-based metallic glasses, which display exceptionally high hardness or a remarkably low modulus. Notably, our architecture can not only explore uncharted regions in the targeted compositional space but also permits self-improvement after experimental validated data points are added to the initial dataset for subsequent cycles of data generation, hence paving the way for the customized design of amorphous solids without human intervention.</p>

Al-rich AlGaN Alloys: Unique Materials for Deep UV LEDs

Energy bandgap of AlxGa1−xN alloys can be tuned systematically from ∼ 3.4 to 6.1 eV by changing the alloy composition (x) from 0 to 1 and the direct bandgap nature is maintained in the entire range of alloy compositions which make the AlGaN alloys suitable materials for the development of light emitting diodes (LEDs) covering the ultraviolet (UV) spectral region from 210 to 400 nm. For LEDs in the deep UV regions (λ < 300 nm), Al-rich AlGaN alloys of Al content higher than 50% are required. Deep UV LEDs have applications in a wide range of fields including display, disinfection, medical, sensing, and communication. With recent progress in the material growth and electrical conductivity, Al-rich AlGaN alloys have emerged as unique wideband gap materials for the development of deep UV LEDs. In this review article, how the progress of Al-rich AlGaN alloys has made in terms of the material growth and electrical conductivity leading its emergence as deep UV materials have been reviewed. Challenges and prospects of the deep UV LEDs to improve the performance of the devices will also be discussed.

Pulse Electrodeposition of High Moment-High Resistivity Cofex (X=P, O) Alloys and Multilayers for Inductor Application

Growing application of magnetic thin films and inductor chips for analog circuits in mobile phones, MEMS and defense sector technologies rise the need for development of new allows with low energy losses to serve as core material during electromagnetic induction process. Electrodeposition is a cost effective approach to achieve this. The new alloys and their electrodeposition/synthesis process foresee an immediate and direct implementation in future product designs and development and can be easily integrated in an existing manufacturing schemes. The presented work leverages earlier results related to electrochemical synthesis of ferromagnetic alloys. In particular, the work on electrodeposition process for high magnetic moment alloys such as CoNiFe and CoFe i,ii,iii, studies of additive incorporation phenomenon in magnetic alloysi v,v,vi and studies of oxide/hydroxide incorporation in magnetic alloys through the interfacial precipitation process vii,viii,ix. Results will be presented describing synthesis process and bath chemistry for highly resistive CoFeX alloys (X=O and/or P) using electrodeposition process with simultaneous Fe(OH)3 precipitation/incorporation and/or (PO3)3- and (H2PO2)- reduction. Fe-oxide/hydroxide and P inclusions in CoFe matrix serve as resistivity controlling phase in the bulk alloy and as a highly resistive barrier layer in the CoFeX/X laminated structures. The main result is design of a a cost-effective electrodeposition process and solution chemistry yielding the CoFeX alloys in composition range where the maximum possible magnetic moment and permeability is expected (Ms ≈ 2.4 T, μ > 1000). The overall content of the “X” component is designed to yield resistivity above 100 μΩcm. These alloys are tested for high frequency applications and their Snoek limit is identified. The correlation between the CoFeX alloys and CoFeX/X laminates properties and their metallurgical structure is discussed.i) S.R. Brankovic, N. Vasiljevic, and N. Dimitrov. “Applications to magnetic recording and microelectronic technologies.” Modern Electroplating (2010): 573-615.ii) S.R. Brankovic, N. Vasiljevic, T. J. Klemmer, and E. C. Johns. Journal of the Electrochemical Society 152, (2005): C196-C202.iii) S.R. Brankovic, X.M. Yang, T. J. Klemmer, and M. Seigler. IEEE Transactions on Magnetics 42, (2006): 132-139.iv) S.R. Brankovic, R. Haislmaier, and N. Vasiljevic. Electrochemical and Solid-State Letters 10, (2007): D67-D71.v) J. George, J. Rantschler, S. Bae, D. Litvinov, and S.R. Brankovic, Journal of the Electrochemical Society 155, (2008): D589-D594.vi) S.R. Brankovic, Electrochimica Acta 84 (2012): 139-144.vii) S.R. Brankovic, S. Bae, and D. Litvinov, Electrochimica Acta 53, (2008): 5934-5940.viii) J. George, S. Elhalawaty, A. J. Mardinly, R. W. Carpenter, D. Litvinov, and S.R. Brankovic, Electrochimica Acta 110 (2013): 411-417ix) S. Elhalawaty, R. W. Carpenter, J. George, and S. R. Brankovic. Journal of the Electrochemical Society 158, (2011): D641-D646.2011): D641-D646.

Investigations of Electrochemical Characteristics of Mg-Al-Ca Alloys

Magnesium alloys possess a high strength-to-density ratio, thereby increasingly being utilized as lightweight structural materials in a range of industrial applications. Nevertheless, to compete with established materials like aluminum alloys, it is essential to understand the corrosion behavior of Mg and its alloys, as their high reactivity hampers industrial application. The addition of Ca to wrought Mg-Al alloys has gained attention for its ability to improve mechanical properties while also enhancing processing behavior. However, the wide range of alloy compositions within the class of Mg-Al-Ca alloys results in a variety of different corrosion properties. Consequently, this study contributes by investigating the corrosion behavior of two Mg-Al-Ca alloys, highlighting the influence of chemical composition and microstructure.

Image-driven deep-learning-enabled automatic microstructural recognition

The deep learning (DL) method consisting of a convolutional neural network (CNN) was employed to automate the task of microstructural recognition and classification to identify dendritic characteristics in metallic microstructures. Dendrites are an important feature that decide the mechanical properties of an alloy; further, the dendritic arm spacing is critical in ascertaining the values of strength and ductility. The current work was divided into two tasks – namely, classification of microstructures into dendritic and non-dendritic microstructures (task 1) and further classification of the dendritic microstructures into longitudinal and transverse cross-sectional views (task 2). The data set comprised micrographs from experimental and online sources covering a broad range of alloy compositions, micrograph magnifications and orientations. The tasks were achieved by employing a four-layered CNN to yield an accuracy of 97.17 ± 0.64% for task 1 and 87.86 ± 1.07% for task 2 independently. The employment of the DL model for classification of microstructures circumvents the feature extraction step while ensuring high accuracy. This work reduces dependency on skilled and experienced researchers and expedites the material development cycle.

Multimaterial direct energy deposition: From three-dimensionally graded components to rapid alloy development for advanced materials

Laser-based direct energy deposition (L-DED) with blown powder enables the simultaneous or sequential processing of different powder materials within one component and, thus, offers the possibility of additive multimaterial manufacturing. Therefore, the process allows a spatially resolved material allocation and fabrication of sharp or even graded material transitions. Within this contribution, the latest results from two major research fields in multimaterial L-DED—(I) automation and (II) rapid alloy development of high entropy alloys (HEAs) by in situ synthesis—shall be presented. First, an automated multimaterial deposition process was developed, which enables the automated manufacturing of three-dimensionally graded specimens. For this, a characterization of the deposition system regarding powder feeding dynamics and resulting powder mixtures in the process zone was conducted. The obtained system characteristics were used to achieve a three-dimensional deposition of specified powder mixtures. The fabricated specimens were analyzed by energy-dispersive x-ray spectroscopy, scanning electron microscopy, and micro hardness measurement. The research demonstrates the increasing readiness of L-DED for the fabrication of multimaterial components. Second, the latest results from rapid alloy development for HEAs by DED are presented. By the simultaneous usage of up to four powder feeders, a vast range of alloy compositions within the Al–Ti–Co–Cr–Fe–Ni HEA system was investigated. For this, tailored measurement systems such as an in-house developed powder sensor were beneficially used. The study shows the influence of a variation of Al on the phase formation and resulting mechanical properties and demonstrates the potential of L-DED for reducing development times for new alloys.

Monte Carlo simulations of surface segregation to discover new hydrogen separation membranes

Surface compositions play a predominant role in the efficiency and lifetime of membranes and catalysts. The surface composition can change during operation due to segregation, thus controlling and predicting the surface composition is essential. Computational modelling can aid in predicting alloy stability, along with designing surface alloys and near-surface alloys that can outperform existing materials. In this work, a computational model to predict surface segregation in ternary alloys is developed. The model, based on Miedema's semi-empirical model and Monte Carlo simulations, enables to predict long- and short-range ordering in the surface and subsurface layers. It is used to screen a vast range of alloy compositions to design a novel ternary Pd-based material for H2 separation membranes. The addition of specific amounts of Cu and Zr to Pd is expected to reduce poisoning and enhance the permeability as compared to pure Pd.

Effects of Alloying Elements on Solidification Structures and Macrosegregation in Slabs

A Cellular Automaton-Finite Element (CAFE) model and a secondary dendrite arm spacing (SDAS) model are established to study the evolutionary behavior of the macrostructure and the secondary dendrites on a 295 × 2270 mm2 slab cross-section of experimental steel, respectively. The relationship between the element content, SDAS, equiaxed crystal ratio (ECR) and macrosegregation in continuously cast experimental slabs was studied comprehensively. It is found that with the increase in carbon content, the ECR increases at first and then decreases, and the ECR reaches the maximum value when the carbon content is 0.3%. With the increase in carbon content, the SDAS and average grain size of the equiaxed crystal zone increase, whereas the Si and Al content evidently affects the SDAS and average grain size of the equiaxed crystal zone to a greater extent than the Mn content. In addition, the SDAS can be reduced by reducing the content of C and Si within the acceptable range of alloy composition.

Phase stability of ( AlxGa1−x)2O3 polymorphs: A first-principles study

Monoclinic ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ and ${({\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x})}_{2}{\mathrm{O}}_{3}$ alloys are wide-band-gap semiconductors with promising applications in power electronics. Although the physical properties of monoclinic ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ ($\ensuremath{\beta}$ phase) have been extensively explored, information is lacking about other phases ($\ensuremath{\alpha}, \ensuremath{\gamma}, \ensuremath{\kappa}$) of ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ and related alloys. Here we use density functional theory to assess the phase stability of different polymorphs of ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ and ${({\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x})}_{2}{\mathrm{O}}_{3}$ alloys at both zero and finite temperatures. Due to the preference of Al for the octahedral site, the $\ensuremath{\gamma}$ and $\ensuremath{\kappa}$ phases of ${({\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x})}_{2}{\mathrm{O}}_{3}$ exhibit a minimum enthalpy of formation at 62.5% and 50% Al concentrations, respectively. Relative to the other phases, the enthalpy of formation of the $\ensuremath{\gamma}$ phase is the highest over the entire range of alloy compositions. We examined the effect of strain arising from pseudomorphic growth of (010)-oriented ${({\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x})}_{2}{\mathrm{O}}_{3}$ films on $\ensuremath{\beta}\ensuremath{-}{\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ substrates and found that the alloys become less stable. At finite temperature we found that the lattice vibrations tend to stabilize the $\ensuremath{\kappa}$ phase and destabilize the $\ensuremath{\alpha}$ and $\ensuremath{\gamma}$ phases, referenced to the monoclinic phase. This can be attributed to the greater phonon density of states of the $\ensuremath{\kappa}$ phase at low frequencies. A unique configurational entropy that is present in the $\ensuremath{\gamma}$ phase due to the cation vacancy disorder plays a substantial contribution in stabilizing the $\ensuremath{\gamma}$ phase at finite temperature, particularly at 50% Al concentration. Our study provides a comprehensive overview of stability of different phases of ${({\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x})}_{2}{\mathrm{O}}_{3}$, offering insights into the driving forces for polymorph formation that should prove useful for improved control over phase-pure growth of these important alloys.

Thermodynamic and kinetic analysis of ternary intermetallics formation in Al–Cu–La alloy

The thermodynamic and kinetic analysis of rare earth (RE) intermetallics formation in Al–Cu–La alloy was carried out in this study. The formation enthalpy, excess entropy, excess Gibbs free-energy and activity of each component of Al–Cu–La ternary alloy were calculated combining Miedema model with Toop model. The calculated results show that the formation enthalpy, excess entropy and excess Gibbs free-energy of Al–Cu–La ternary alloy are all negative in the whole alloy composition range. The activities of Al, Cu and La are all tiny in the central zone of composition triangle of Al–Cu–La ternary alloy, indicating that Al, Cu and La components are easy to form ternary intermetallics. Moreover, the parabolic growth kinetics equation of RE intermetallics was derived integrating the Fick's second law with the mass balance law. According to the parabolic growth rate, the thickness of the RE intermetallics increases in proportion to the square root of the diffusion time.

Topological control of liquid-metal-dealloyed structures

The past few years have witnessed the rapid development of liquid metal dealloying to fabricate nano-/meso-scale porous and composite structures with ultra-high interfacial area for diverse materials applications. However, this method currently has two important limitations. First, it produces bicontinuous structures with high-genus topologies for a limited range of alloy compositions. Second, structures have a large ligament size due to substantial coarsening during dealloying at high temperature. Here we demonstrate computationally and experimentally that those limitations can be overcome by adding to the metallic melt an element that promotes high-genus topologies by limiting the leakage of the immiscible element during dealloying. We further interpret this finding by showing that bulk diffusive transport of the immiscible element in the liquid melt strongly influences the evolution of the solid fraction and topology of the structure during dealloying. The results shed light on fundamental differences in liquid metal and electrochemical dealloying and establish a new approach to produce liquid-metal-dealloyed structures with desired size and topologies.

Nontrivial Doping Evolution of Electronic Properties in Ising-Superconducting Alloys.

Transition metal dichalcogenides offer unprecedented versatility to engineer 2D materials with tailored properties to explore novel structural and electronic phase transitions. In this work, the atomic-scale evolution of the electronic ground state of a monolayer of Nb1- δ Moδ Se2 across the entire alloy composition range (0 < δ< 1) is investigated using low-temperature (300 mK) scanning tunneling microscopy and spectroscopy (STM/STS). In particular, the atomic and electronic structure of this 2D alloy throughout the metal to semiconductor transition (monolayer NbSe2 to MoSe2 ) is studied. The measurements enable extraction of the effective doping of Mo atoms, the bandgap evolution and the band shifts, which are monotonic with δ. Furthermore, it is demonstrated that collective electronic phases (charge density wave and superconductivity) are remarkably robust against disorder and further shown that the superconducting TC changes non-monotonically with doping. This contrasting behavior in the normal and superconducting state is explained using first-principles calculations. Mo doping is shown to decrease the density of states at the Fermi level and the magnitude of pair-breaking spin fluctuations as a function of Mo content. These results paint a detailed picture of the electronic structure evolution in 2D TMD alloys, which is of utmost relevance for future 2D materials design.

Comparison of LPBF processing of AlSi40 alloy using blended and pre-alloyed powder

Elemental powders or pre-alloyed powders can be blended to form a powder stock with new compositions. In-situ alloying of blended powder mixtures during LPBF processing speeds up the alloy development process as it allows composition adjustment. Pre-alloyed powder is typically used in industrial settings to ensure consistency of the built material, whereas blended powders are used to experiment with new alloy compositions. In this research, we compare a range of binary alloy compositions built from blended elemental powder and pre-alloyed powder to evaluate how the feedstock powder affects the built material. The alloy is a lightweight alloy with a low coefficient of thermal expansion, comprised of Al and Si. The following compositions were formed by mixing pure Al and Si powder: AlSi38, AlSi40 and AlSi42, and pre-alloyed AlSi40 powder was also used. Parametric studies were performed for both the blended and pre-alloyed powders. It was found that the optimum process parameters for the blended and pre-alloyed powder were different. The line energy for pre-alloyed powder was selected to be 0.150 J/mm (300 W, and 2000 mm/s) which yielded a density of 99.5% of the theoretical density. The optimal density for the blended powders was 99.07-99.16% which was also achieved with 0.150 J/mm (375 W, 2500 mm/s). The alloys are brittle, with Young's modulus 86-99 GPa. Coefficient of thermal expansion (CTE) reduced with increasing Si content, material built from pre-alloyed powder had 5% higher CTE than material built from blended powder.

Computational design of thermoelectric alloys through optimization of transport and dopability.

Alloying is a common technique to optimize the functional properties of materials for thermoelectrics, photovoltaics, energy storage etc. Designing thermoelectric (TE) alloys is especially challenging because it is a multi-property optimization problem, where the properties that contribute to high TE performance are interdependent. In this work, we develop a computational framework that combines first-principles calculations with alloy and point defect modeling to identify alloy compositions that optimize the electronic, thermal, and defect properties. We apply this framework to design n-type Ba2(1-x)Sr2xCdP2 Zintl thermoelectric alloys. Our predictions of the crystallographic properties such as lattice parameters and site disorder are validated with experiments. To optimize the conduction band electronic structure, we perform band unfolding to sketch the effective band structures of alloys and find a range of compositions that facilitate band convergence and minimize alloy scattering of electrons. We assess the n-type dopability of the alloys by extending the standard approach for computing point defect energetics in ordered structures. Through the application of this framework, we identify an optimal alloy composition range with the desired electronic and thermal transport properties, and n-type dopability. Such a computational framework can also be used to design alloys for other functional applications beyond TE.

Analysis of the CHARM Cu‐alloy reference materials using excimer ns‐LA‐ICP‐MS: Assessment of matrix effects and applicability to artefact provenancing

AbstractExcimer nano‐second laser ablation inductively coupled plasma mass spectrometry (ns‐LA‐ICP‐MS) is an important tool in chemical characterization of Cu alloys. However, variable matrix‐induced elemental fractionation in Cu alloys poses a significant challenge. We systematically investigate this issue by analysing the Cultural Heritage Alloy Reference Material Set (CHARM) of Cu alloy targets. The extent to which silicate glass reference materials can be used when analysing Cu alloy targets is determined, as is the optimal internal standard, for a wide range of Cu alloy compositions. Analyses were further optimized by quantitative assessments of the use of CHARM end‐member materials as external standards for other CHARM Cu alloy targets. The variable magnitude of the observed matrix effects is most readily explained by variations in Cu/Zn ratios and resulting differences in melting and boiling points, compared with external reference materials, making the Zn‐rich Cu alloy targets most prone to matrix effects. With the correct choice of an external matrix‐matched standard (Pb‐rich CHARM reference material 32X LB14F) and internal element standardization, an accuracy of &lt; 20% can be achieved for virtually all elements of interest in brass and bronze artefacts, which is a significant improvement compared with the use of glass external reference materials.

Properties of orthorhombic Ga2O3 alloyed with In2O3 and Al2O3

Ga2O3 is a promising wide-bandgap material for electronic applications. The metastable orthorhombic κ phase is of particular interest due to its large predicted spontaneous electrical polarization. Here, we investigate how the properties of the orthorhombic phase can be tuned by alloying with In2O3. In particular, we determine how the lattice constants, bandgap, and band offsets change over the full range of possible alloy compositions. For completeness, we also compare to alloys with Al2O3. Lattice constants decrease linearly with Al content, while the bandgaps and conduction-band offsets increase non-linearly, with a bowing of 1.41 eV. Alloying with In2O3 allows to increase the lattice constants linearly and to decrease the bandgaps and conduction-band offsets non-linearly, with a bowing of 0.31 eV. Alloying, therefore, allows for the modification of the structural and electronic properties over a wide range, opening the possibility to tailor the alloy properties to specific applications.