Nanoindentation Criteria for Combinatorial Thin Film Libraries

Advanced Engineering Materials · 2026-02-28

Employing high‐throughput characterization techniques on combinatorially synthesized thin film material libraries offers a pathway for accelerating the discovery and development of novel materials. In particular, nanoindentation is useful for rapidly screening composition‐property relationships. However, despite its widespread use, current literature reveals methodological inconsistencies regarding the number of indents performed per composition and the total number of compositions sampled. This work utilizes a Cu x Ni (1− x ) library as a model system to investigate nanoindentation data collection and optimize experimental throughput. Interpolation methods are applied to data subsets to identify critical regions of interest and capture material trends. The employed framework indicates that characterizing as few as 15% of the total compositions is sufficient for predicting both hardness and modulus trends across the Cu x Ni (1− x ) library. This approach can be used as a baseline for investigating more compositionally complex systems, enabling faster generation of datasets, materials discovery, and training sets for machine learning models.

Composition-driven nanotwin engineering in sputtered Ni-Fe and Ni-Cr films: linking fault energetics to twin thickness

Acta Materialia · 2026-01-06 · 3 citations

opXRD: Open Experimental Powder X‐Ray Diffraction Database

Advanced Intelligent Discovery · 2025-06-20 · 2 citations

Powder X‐ray diffraction (pXRD) experiments are a cornerstone for materials structure characterization. Despite their widespread application, analyzing pXRD diffractograms still presents a significant challenge to automation and a bottleneck in high‐throughput discovery in self‐driving labs. Machine learning promises to resolve this bottleneck by enabling automated powder diffraction analysis. A notable difficulty in applying machine learning to this domain is the lack of sufficiently sized experimental datasets, which has constrained researchers to train primarily on simulated data. However, models trained on simulated pXRD patterns showed limited generalization to experimental patterns, particularly for low‐quality experimental patterns with high noise levels and elevated backgrounds. With the Open Experimental Powder X‐ray Diffraction Database (opXRD), we provide an openly available and easily accessible dataset of labeled and unlabeled experimental powder diffractograms. Labeled opXRD data can be used to evaluate the performance of models on experimental data and unlabeled opXRD data can help improve the performance of models on experimental data, for example, through transfer learning methods. We collected 92,552 diffractograms, 2179 of them labeled, from a wide spectrum of material classes. We hope this ongoing effort can guide machine learning research toward fully automated analysis of pXRD data and thus enable future self‐driving materials labs.

Modern strategies in classical fields of nanoindentation: Semiconductors, ceramics, and thin films

MRS Bulletin · 2025-05-30 · 4 citations

Over the past three decades, nanoindentation has continuously evolved and transformed the field of materials mechanical testing. Once highlighted by the groundbreaking Oliver-Pharr method, the utility of nanoindentation has transcended far beyond modulus and hardness measurements. Today, with increasing challenges in developing advanced energy generation and electronics technologies, we face a growing demand for accelerated materials discovery and efficient assessment of mechanical properties that are coupled with modern machine learning-assisted approaches, most of which require robust experimental validation and verification. To this end, nanoindentation finds its unique strength, owing to its small-volume requirement, of fast-probing and providing a mechanistic understanding of various materials. As such, this technique meets the demand for rapid materials assessment, including semiconductors, ceramics, and thin films, which are integral to next-generation energy-efficient and high-power electronic devices. Here, we highlight modern nanoindentation strategies using novel experimental protocols outlined by the use of nanoindentation for characterizing functional structures, dislocation engineering, high-speed nanoindentation mapping, and accelerating materials discovery via thin-film libraries. We demonstrate that nanoindentation can be a powerful tool for probing the fundamental mechanisms of elasticity, plasticity, and fracture over a wide range of microstructures, offering versatile opportunities for the development and transition of functional materials. Graphical abstract: Modern strategies for nanoindentation in electronic systems, functional ceramics, heterogeneous structures, and thin films.

Revisiting grain boundary segregation and precipitation in nanocrystalline metallic alloys

Scripta Materialia · 2025-10-01 · 1 citations

Nanostructured metallic alloys exhibit an inherently high volumetric density of grain boundaries, which could be stabilized either through kinetic pinning effects, thermodynamic solute enrichment of grain boundaries, or a combination of both. While there have been a multitude of recent strides identifying candidate systems for realizing stable nanocrystalline grain structures, experimental literature often relies on indirect evidence that is supplemented by computational models to ascertain fundamental stabilization mechanisms. This work investigates solute behavior in annealed Fe-W and Fe-Zr alloys through the lens of competing solute segregation and oxide precipitation. Ultimately, the absolute difference between enthalpies of segregation and oxide formation was demonstrated as a useful qualitative metric for evaluating nanocrystalline systems for potential grain boundary enrichment. The importance of high-resolution characterization is underscored, as seemingly thermodynamic stabilization can be easily convoluted with kinetically pinning features at the nanoscale.

Creating and leveraging actionable mission statements

Organizational Dynamics · 2025-09-22 · 1 citations

Deformation Behavior of Optical Ceramic Nanomultilayers: The Role of Aperiodicity

Advanced Engineering Materials · 2025-09-21

Aperiodicity in ceramic nanomultilayers (NMs) has been shown to improve coating functionality, namely, for optimized optical behavior, while the effects of aperiodic layer thicknesses on mechanical deformation remain poorly understood. In this article, the relationships between individual layer thicknesses, optical transmittance, and mechanical behavior are investigated for AlN/Al 2 O 3 , YSZ/Al 2 O 3 , and AlN/YSZ nanomultilayered coatings. These NMs are synthesized with aperiodic layer configurations from individual constituents selected for their optical constants, elastic modulus, and hardness values; the layer designs of select samples are optimized to achieve a transmittance exceeding 90% across the ultraviolet, visible, and near‐infrared spectral range. The effect of aperiodicity on the mechanical properties and deformation is explored at various length scales via nanoindentation, micropillar splitting, and Vickers microindentation. However, competing factors, such as interface type and local microstructure, also play critical roles. It is observed that layer composition strongly influences fracture toughness, as samples with amorphous Al 2 O 3 layers and crystalline/amorphous interfaces exhibit superior mechanical performance and the highest fracture toughness values. Yet, distinct failure modes, including delamination and intergranular fracture, across the different nanomultilayered architectures highlight the relation of optical and mechanical properties to local volume fractions within aperiodic layer stacks and interface characteristics in the coating design.

Ruddlesden-Popper chalcogenides push the limit of mechanical stiffness and glass-like thermal conductivity in single crystals

Nature Communications · 2025-07-02 · 4 citations

Insulating materials featuring ultralow thermal conductivity for diverse applications also require robust mechanical properties. Conventional thinking, however, which correlates strong bonding with high atomic-vibration-mediated heat conduction, led to diverse weakly bonded materials that feature ultralow thermal conductivity and low elastic moduli. One must, therefore, search for strongly-bonded single crystals in which heat transport is impeded by other means. Here, we report intrinsic, glass-like, ultralow thermal conductivity and ultrahigh elastic-modulus/thermal-conductivity ratio in single-crystalline Ruddlesden-Popper Ban+1ZrnS3n+1, n = 2, 3, which are derivatives of BaZrS3. Their key features are strong anharmonicity and intra-unit-cell rock-salt blocks. The latter produce strongly bonded intrinsic superlattices, impeding heat conduction by broadband reduction of phonon velocities and mean free paths and concomitant strong phonon localization. The present study initiates a paradigm of “mechanically stiff phonon glasses”. Here, the authors report on the thermal and mechanical properties of Ruddlesden-Popper phases (Ban+1ZrnS3n+1, n = 2 and 3) of a perovskite chalcogenide (BaZrS3) that push to extreme limits and defy the century-old relation between thermal conductivity and interatomic bond strength.

Investigating phase regimes via combinatorial synthesis: A pathway to tailored materials libraries

Materials & Design · 2025-03-28 · 4 citations

• Combinatorial synthesis of an Fe-W material library via magnetron sputtering. • Screened material library via high-throughput X-ray and electron microscopy techniques. • Deconvoluted and quantified composition and growth rate effects on film microstructure. • Coatings exhibit growth rate effects after annealing induced recrystallization. • Growth regimes in material libraries can be tailored via synthesis parameters. Combinatorial magnetron sputtering has been implemented to synthesize compositionally graded thin film material libraries, enabling rapid exploration of structure–property trends via high-throughput characterization techniques. In this study, an Fe-W material library with 169 unique samples is sputter-deposited to investigate the amorphous-crystalline transition across the Fe – 9.4 to 45.5 at.% W range. X-ray diffraction and electron microscopy techniques reveal trends in film microstructure and morphology that are intrinsically connected to alloy composition but further shown to be dependent on synthesis conditions by decoupling composition and thickness/deposition rate effects. Samples are classified into three distinct regimes: crystalline, mixed-mode, or X-ray amorphous. By deconvoluting and analyzing the interplay between composition and deposition rate, it is shown that growth kinetics can sufficiently alter phase formation to dominate compositionally driven mechanisms within a single material library. This observation is verified after heat-treatment to 750 °C on selected samples. Particularly within the mixed-mode regime, the relationship between solute content and deposition rate is quantified, thereby enabling the tailoring of materials libraries investigations of composition and growth rate effects. Overall, this work combines the expansive compositional space in a combinatorial library with sputtering science to identify microstructural and phase regime boundaries in the Fe-W system.

Synthesis and characterization of aperiodic multifunctional AlN/Al2O3 nanomultilayers

Thin Solid Films · 2025-02-25 · 1 citations