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The interface strengthening effect in nanoscale metallic multilayers is influenced by the enthalpy of mixing, which governs the chemical distribution and interface microstructure. In this study, Al/Ni multilayers were fabricated by magnetron sputter deposition, exhibiting an ultrahigh peak hardness of 9.5 GPa─the highest reported for face-centered cubic multilayer systems. Advanced electron microscopy revealed extensive interdiffusion at the Al/Ni interfaces and the formation of intermetallic bonds at both interfaces and grain boundaries. A modified confined layer slip model is proposed, accounting for energy changes associated with trailing dislocations propagating through interfaces or grain boundaries due to intermetallic bond formation. The model aligns closely with experimental data, demonstrating that intermetallic bond formation in Al/Ni multilayers significantly enhances interface strengthening, counteracting the weakening effects of interface diffusion. This mechanism may also account for the high peak hardness observed in other multilayer systems with large negative enthalpies of mixing.
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http://dx.doi.org/10.1021/acs.nanolett.5c02939 | DOI Listing |
Nano Lett
August 2025
Institute of Energy Materials and Devices, Structure and Function of Materials (IMD-1), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
The interface strengthening effect in nanoscale metallic multilayers is influenced by the enthalpy of mixing, which governs the chemical distribution and interface microstructure. In this study, Al/Ni multilayers were fabricated by magnetron sputter deposition, exhibiting an ultrahigh peak hardness of 9.5 GPa─the highest reported for face-centered cubic multilayer systems.
View Article and Find Full Text PDFSci Rep
May 2025
Department of Physics and Astronomy, Uppsala University, Box 516, 751 20, Uppsala, Sweden.
The predictive accuracy of density functional theory (DFT) for alloy formation enthalpies is often limited by intrinsic energy resolution errors, particularly in ternary phase stability calculations. In this work, we present a machine learning (ML) approach to systematically correct these errors, improving the reliability of first-principles predictions. A neural network model has been trained to predict the discrepancy between DFT-calculated and experimentally measured enthalpies for binary and ternary alloys and compounds.
View Article and Find Full Text PDFMicromachines (Basel)
March 2025
Chair of Microintegration and Reliability, Faculty of Natural Sciences and Technology, Saarland University, 66123 Saarbrücken, Germany.
Reactive bonding can overcome the issues associated with conventional soldering processes, such as potential damage to heat-sensitive components and the creation of thermomechanical stress due to differing coefficients of thermal expansion. The risk of such damage can be reduced by using localized heat sources like reactive multilayer systems (RMS), which is already a well-established option in the field of silicon or metal bonding. Adapting this process to other materials, such as low temperature co-fired ceramics (LTCC), is difficult due to their differing properties, but it would open new technological possibilities.
View Article and Find Full Text PDFHeliyon
August 2024
Mechanical Engineering Department, Hamedan University of Technology, Hamedan, Iran.
The accurate evaluation of the effective mechanical properties of composites mainly depends on the characteristics of representative volume elements (RVEs). This paper mainly investigates the RVE size. Additionally, the effect of volume fraction of reinforcement, the edge effect, and RVE types on the critical size are discussed.
View Article and Find Full Text PDFPhys Chem Chem Phys
April 2024
Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, via Marengo 2, 09123 Cagliari, Italy.
This work addresses a long standing question in the field of mechanochemistry, namely the role of mesostructure in the initiation of self-propagating high-temperature reactions in exothermic chemical systems, commonly referred to as ignition. In an attempt to find robust evidence in this regard, we compare the ignition behaviour of equimolar Al-Ni powder mixtures and equimolar Al-Ni multilayers. To achieve the best possible control of experimental conditions and allowing high reproducibility, we used elemental powders sieved in the range between 20 μm and 44 μm, and multilayers with bi-layer thickness between 10 nm and 800 nm.
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