Titanium nitride (TiN) coatings are widely used as wear-protection layers on cutting and forming tools due to their high hardness and chemical stability. However, the adhesion of TiN on substrates, such as silicon and steel (1.4301), can be insufficient for a given application. This study investigates the effect of atmospheric pressure plasma pretreatment on the adhesion behavior of TiN coatings. The surface modification is analyzed using confocal laser scanning microscopy after plasma treatment with argon (Ar) and argon/hydrogen (Ar/H2) gas mixtures. Subsequently, the samples are coated by reactive magnetron sputtering. Adhesion performance is evaluated by cross-cut test, while X-ray diffraction is employed to detect possible changes in the crystalline structure of the coatings. Plasma treatment deoxidizes and activates the surface, which enhances adhesion between coating and substrate. Ar/H2 plasma, in particular, significantly improves coating adhesion compared to untreated samples. These findings demonstrate that plasma-surface pretreatment improves coating durability and has the potential to extend tool lifetime in industrial applications.

Microstructure, hardness, physical properties, and corrosion response of Al‐Cu intermetallic compounds (IMCs) are investigated with the aim of establishing optimization guidelines for the Al‐Cu bimetallic compound casting process. Five Al‐Cu samples with chemical compositions promoting stable single phases ( and at ambient temperature are produced via induction casting. The microstructural and compositional analysis, however, evidenced the precipitation of secondary phases in the and θ samples. It is also observed that θ can directly transform into , due to a kinetically enabled process. Physical properties, including electrical conductivity, thermal diffusivity, and specific heat, are measured, and the thermal conductivity is calculated accordingly. It is observed that the copper‐rich IMCs have lower thermal conductivity compared to other Al‐Cu IMCs. The nonmonotonous relationship between physical properties and chemical composition is correlated to the crystallography of the phases and the precipitation of secondary phases. Experimental validation demonstrated a significant impact of casting defects (over 30%) on the thermal conductivity of the interfaces. Moreover, the overall hardness of cast samples showed significant deviation from previous studies, emphasizing the impact of the sample production method. Finally, corrosion assessment using a 0.5% NaCl solution suggested galvanic corrosion as the primary corrosion mechanism.

Laser surface texturing enables precise control of micro- and nano-scale topographies that govern wettability, adhesion, friction, and interfacial bonding. In this study, nanosecond-pulsed laser ablation under oxygen-free processing conditions is established as a scalable and automation-ready approach for the simultaneous removal of native oxides and the functional texturing of aluminum and copper surfaces for advanced manufacturing applications. By systematically varying pulse overlap, surface morphologies are tuned from isolated ablation craters to homogeneous textures and, at high overlap, to a melt-dominated regime with increased roughness and effective surface area, enabling application-specific tailoring of interfacial properties. Material-dependent near-surface modifications are observed: aluminum exhibits increased hardness and stiffness, while copper shows localized softening, highlighting fundamentally different laser–matter interaction mechanisms relevant for surface engineering. Microstructural evolution and residual stress development depend on overlap and accumulated fluence, with high overlap promoting texture reduction and stress relaxation. X-ray photoelectron spectroscopy confirms effective oxide removal and exposure of metallic copper under oxygen-free conditions, while identical processing in air leads to pronounced reoxidation; aluminum shows the same qualitative trend. The functional relevance of laser-textured, oxide-free surfaces is demonstrated for adhesive bonding, cold roll bonding, compound casting, and laser beam brazing, enabling improved wetting, enhanced interfacial adhesion, reduced critical deformation for solid-state bonding, and flux-free aluminum–copper joining. The results establish oxygen-free ns-pulsed laser ablation as a versatile surface engineering route that integrates cleaning, oxide-removal and functional structuring in a single step, offering broad potential for advanced and automated manufacturing in joining processes.

Cold roll bonding (CRB), a process that conventionally requires high degrees of deformation, is employed under extreme high vacuum (XHV)-adequate conditions to promote bond formation. Specifically, surface pretreatments via laser ablation and mechanical brushing are compared for Cu-Al bonding in oxygen-free environments with a focus on bond strength evolution, interface morphology, residual stress states and crystallographic texture development. Laser ablation treatment led to superior bond strengths at all tested reduction levels, while both methods converged to similar strength values at high deformation levels. Laser ablation creates interfaces with increased true contact area through enhanced microscopic irregularities. Residual stress measurements show that laser ablation induces beneficial residual tensile stresses, whereas brushing generates residual compressive stresses. In addition, laser-treated specimens retain preferred cube textures at the surfaces for both bonding partners, reducing crystallographic mismatch. The enhanced performance of laser ablation arises from synergistic mechanisms, as detailed in a multimechanistic framework to foster understanding of CRB under oxygen-free conditions.

Cold roll bonding conventionally requires high deformation degrees for successful bonding and faces limitations due to surface oxidation of the metal sheets employed. Recent investigations under extreme high vacuum (XHV)-adequate conditions indicate that even when oxidation is effectively suppressed, significant differences in bonding behaviour persist. This observation suggests that bond initiation under these conditions is governed by surface and subsurface properties beyond oxide layers. The present study systematically assesses the influence of different surface preparation methods, including mechanical brushing, ns-pulsed laser ablation, and dielectric barrier discharge (DBD) plasma treatment, on copper-aluminium cold roll bonding under XHV-adequate conditions. Surface analysis revealed distinct treatment-specific surface states and process-induced modifications in topography, mechanical properties, residual stresses, and microstructure. Laser ablation enabled bond formation at much lower deformation thresholds than conventional brushing. In contrast, plasma treatment did not produce consistent bonds despite partial oxide reduction. The findings support an integrated model in which successful bond formation under oxide-free conditions depends on five key factors: active metallic surfaces without passivation, engineered topography that enhances the contact area, mechanical property gradients that facilitate localised deformation, favourable residual stress distribution, and preserved microstructural features.

The phase composition, microstructure and mechanical properties of arc-melted eutectic Nb-18.7Si (at.-%) alloys with different nano-ceramic particle addition (Al2O3, TiC, SiC, 5 mol.-%) were investigated. The results showed that ceramic Al2O3 and TiC nanoparticle are thermally and chemically stable and can be used to tailor phase composition and refine the microstructure, while SiC dissolves completely in the melt. Al2O3 and TiC nano- particle were found mainly in two different areas: (1) at grain boundaries of eutectic structures and (2) on the phase boundaries of silicides inside the eutectics. The presence of the particles refined the microstructure down to nano-scale lamellae by functioning as heterogeneous nuclei for the silicide phase. Without nano particle addition, the Nb-18.7Si alloy was mainly composed of Nb solid solution (Nbss) and Nb3Si. The addition of 5 mol.% Al2O3 promoted the decomposition of the Nb3Si phase and an ultrafine nano-scale lamellar eutectic structure (Nbss + alpha-Nb5Si3) formed. With the addition of 5 mol.-% TiC, primary Nb3Si and coarse Nbss were observed, as well as fine eutectic Nbss + gamma-Nb5Si3 structures. The complete dissolution of SiC led to a hypereutectic alloy with primary Nb3Si and gamma-Nb5Si3 phase, coarse Nbss and eutectic Nbss + gamma-Nb5Si3 structures. The compressive strength was increased from 3068 MPa to 3446 MPa by adding 5 mol.-% Al2O3 due to the formation of the high strength alpha-Nb5Si3 phase, the ultrafine nano-scale lamellar structures of Nbss + alpha-Nb5Si3 and the strong interface of Nbss/ alpha-Nb5Si3. However, the small grain size of the Nbss phase was not effective in inhibiting crack propagation. Crack bridging and branching seem to be important mechanisms at the Nbss phase to inhibit crack propagation. Therefore, the size and distribution of Nbss play a key role. The results indicate that a continuous Nbss phase with embedded silicide phase and coarse Nbss phases can inhibit crack propagation.

Eutectic Nb-18.7Si alloys with different ceramic nanoparticle addition (Al2O3, TiC, SiC, 5 mol.-%), prepared by arc-melting, were heat-treated for 24 h at 1500 degrees C. Phase composition, microstructure transition and mechanical properties were investigated. The results show that the gamma-Nb5Si3 and small Nb3Si phases from the as-cast alloy decomposed into alpha-Nb5Si3 and Nbss/alpha-Nb5Si3-eutectoids. Larger Nb3Si phases still existed after heat treatment. Additionally, after heat treatment the Nbss phases were interconnected to a continuous matrix, while silicides appeared coarsened and spherical while being uniformly distributed in the Nbss phase. This effect was most pronounced in the alloy with addition of Al2O3 nanoparticles, due to the ultrafine nano-scale lamellar structures of Nbss + alpha-Nb5Si3 in its as-cast condition. While the added nanoparticles had a strong effect on the initial microstructure of the as-cast state, they showed no noticeable effects like pinning of grain boundaries during heat treatment. A decrease in hardness was observed due to the coarsening of the microstructure and the reduced area fraction of silicide phases. However, the transformation to the coarser microstructure with a continuous Nbss matrix and spherical silicide phases seems to be effective in inhibiting crack propagation by promoting crack deflection and bridging over the Nbss phase.

Refractory high entropy alloys (RHEAs) consisting of high melting point elements, such as Hf, Mo, Nb, Ta, Ti, Mo, and Zr, have shown promising mechanical properties and phase stability at elevated temperatures and, thus, received increasing attention over the last two decades. In the present study, employing experimental and computational methods, the microstructures and mechanical properties of seven different RHEAs, namely, Hf16.6Nb16.6Ta16.6Ti50 (HEA1), HfNbTaTiZr (HEA2), Hf27Nb12Ta10Ti23Zr28 (HEA3), Hf30Nb14Ta10Ti28Zr18 (HEA4), Hf12Nb16Ta35Ti29Zr8 (HEA5), HfMoTaTiZr (HEA6), and MoNbTaTiZr (HEA7) were compared. The nonequilibrium solidification curves calculated using CALPHAD demonstrated that Ta, Nb, and Mo tend to solidify first in the dendrite arms, while the liquid phase becomes enriched with Ti and Zr as solidification progresses. However, depending on the Ta content, Hf is proclaimed to solidify in dendrite arms or interdendritic regions, also supported by thorough experimental characterization. Furthermore, the addition of Mo was demonstrated to increase the hardness and strength of the alloys at the expense of ductility. Finally, HEA1, HEA3, HEA4, and HEA5 demonstrate excellent strength-ductility synergy at room and cryogenic temperatures (-80 degrees C), expanding their service temperature range, promoting their utility in a variety of industrial applications.

The influence of a preceding laser ablation surface treatment on cold roll bonding (CRB) efficiency under extreme high vacuum-adequate (XHV-adequate) conditions were examined. Experimental investigations were conducted in a controlled glovebox environment. The impact of varying laser parameters on the critical reduction required for bonding copper and aluminium sheets was analysed. The results demonstrate a significant reduction in critical deformation necessary for bond formation. Surfaces treated by laser ablation achieve bonding at plastic deformations as low as 0.5%. In comparison, brushed surfaces require a plastic strain of 19% in similar XHV-adequate conditions. Using confocal laser scanning microscopy, a correlation between laser parameters and resulting surface characteristics was established, revealing material-specific surface alterations. Scanning electron microscopy analysis of the bonded interfaces further shows enhanced interfacial deformation in laser-treated specimens, which is characterised by increased waviness and pronounced protrusions. The investigations demonstrate a synergistic effect between laser-induced surface modifications and oxide-free conditions in an XHV-adequate atmosphere, which leads to a significant optimisation of CRB efficiency. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of Society of Manufacturing Engineers (SME). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The digitization of technologies in product manufacturing results in the availability of large amounts of process and product data. To gain knowledge from this data and fully leverage its potential, its structuring and semantically annotation is essential. This allows preserving the context of data generation and makes the data machine-readable and interpretable. Contextualization is the key to generating FAIR (Findable, Accessible, Interoperable, Reusable) data. The documentation of research activities and provenance of generated data is usually achieved by protocols. However, there is often a tension between the desire to document data generation in a structured, semantically rich form and the need to design research and process parameters flexibly as experimental conditions change. To resolve these contradictions, a dynamic model is described that allows to document research activities and implemented into a knowledge and research data management system to resolve these contradictions. The model allows a formal, semantic representation of research steps, parameters and gathered data, while also providing flexibility in the generation of protocol templates and individual experiments through the reuse of semantic building blocks. The approach is carried out within the context of a large collaborative research center, showcasing its use in managing and providing data for heterogeneous research tasks, documentation, and data types across interdisciplinary projects.

In this study, oxidation behavior in as-cast polycrystalline HfNbTaTi3, HfNbTaTiZr, HfMoTaTiZr, and NbMoTaTiZr refractory high-entropy alloys (RHEAs), and the amorphous form of NbMoTaTiZr RHEA, is investigated. Herein, the surfaces of samples undergoing static oxidation experiments at 700, 800, and 900 degrees C using scanning electron microscopy, energy-dispersive X-Ray spectroscopy, X-Ray photoelectron spectroscopy, and X-Ray diffraction are explored. In the corresponding findings, the presence of three different oxidation behaviors in the studied RHEAs is shown: formation of a non-protective scale, powderization and pesting of the sample, and a distinct amorphous oxidation behavior compared to its polycrystalline counterpart. Notably, Nb appears to induce a detrimental effect on the oxidation properties of samples due to the high ratio of volume change between the oxide and the metal. In the current findings, it is also evidenced that Mo can cause catastrophic failure in RHEAs that lack a protective oxide layer. Overall, the results constitute a step forward in enhancing the understanding of oxidation behavior in RHEAs and developing novel oxidation-resistant RHEAs. Oxidation response of four TiTa-based refractory high-entropy alloys is studied. Static oxidation experiments are conducted at 700, 800, and 900 degrees C. Three distinct oxidation behaviors are identified: formation of a non-protective scale, powderization and pesting of the sample, and a distinct amorphous oxidation behavior compared to its polycrystalline counterpart.image (c) 2024 WILEY-VCH GmbH

AbstractArc-melting (AM) as a primary method for casting high entropy alloys (HEAs) ensures rapid alloy screening with minimal material input, high cost-effectiveness, and high cooling rates. However, the limitations of AM on a laboratory scale, particularly its constrained sample size and the necessity for remelting steps to ensure homogeneity, hampers thorough mechanical and functional testing of bulk materials. Therefore, this study features a comparative analysis between AM and vacuum induction-melting (VIM) techniques for High Entropy Shape Memory Alloys (HE-SMAs) production, focusing on the senary alloy Ti16.6Zr16.6Hf16.6Co10Ni20Cu20, known for its potential functional applications and high sensitivity to material inhomogeneity. The alloy’s composition, including high-melting point elements like Hf, Ti and Zr, makes it a well-suited candidate for assessing the capabilities of VIM in producing homogeneous bulk materials. The employment of binary pre-alloys in both AM and VIM processes reduced the necessity for remelting steps and ensured better initial quality for subsequent heat treatments. A homogenization treatment at 900 °C for 100 h of an AM-produced senary alloy showed only slight improvements compared to the same alloy produced via VIM, largely due to the slow diffusion of the larger Hf and Zr atoms from the dendrites into the solid solution. This suggests that VIM can achieve comparable levels of homogenization in substantially less time than required for AM-treated samples. The findings finally indicate that by using VIM, when combined with binary pre-alloys, one achieves more homogeneous alloys with reduced heat-treatment time, making it a viable method for HE-SMA production.

AbstractComplex research problems are increasingly addressed by interdisciplinary, collaborate research projects generating large amounts of heterogeneous amounts of data. The overarching processing, analysis and availability of data are critical success factors for these research efforts. Data repositories enable long term availability of such data for the scientific community. The findability and therefore reusability strongly builds on comprehensive annotations of datasets stored in repositories. Often generic metadata schema are used to annotate data. In this publication we describe the implementation of discipline specific metadata into a data repository to provide more contextual information about data. To avoid extra workload for researchers to provide such metadata a workflow with standardised data templates for automated metadata extraction during the ingest process has been developed. The enriched metadata are in the following used in the development of two repository plugins for data comparison and data visualisation. The added values of discipline-specific annotations and derived search features to support matching and reusable data is then demonstrated by use cases of two Collaborative Research Centres (CRC 1368 and CRC 1153).

Engineering in vacuum or under a protective atmosphere permits the production of materials, wherever the absence of oxygen is an essential demand for a successful processing. However, very few studies have provided quantitative evidence of the effect of oxidized surfaces to tribological properties. In the current study on 99.99% pure copper, it is revealed that tribo-oxidation and the resulting increased abrasive wear can be suppressed by processing in an extreme high vacuum (XHV) adequate environment. The XHV adequate atmosphere was realized by using a silane-doped shielding gas (1.5 vol% SiH4 in argon). To analyse the influence of the ambient atmosphere on the tribological and mechanical properties, a ball—disk tribometer and a nanoindenter were used in air, argon, and silane-doped argon atmosphere for temperatures up to 800 °C. Resistance measurements of the resulting coatings were carried out. To characterize the microstructures and the chemical compositions of the samples, the scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used. The investigations have revealed a formation of η-Cu3Si in silane-doped atmosphere at 300 °C, as well as various intermediate stages of copper silicides. At temperatures above 300 °C, the formation of γ-Cu5Si were detected. The formation was linked to an increase in hardness from 1.95 to 5.44 GPa, while the Young’s modulus increased by 46% to 178 GPa, with the significant reduction of the wear volume by a factor of 4.5 and the suppression of further oxidation and susceptibility of chemical wear. In addition, the relevant diffusion processes were identified using molecular dynamics (MD) simulations.

In the present study, a novel approach is presented to achieve oxygen partial pressures corresponding to extremely high vacuum (XHV) to foster cold roll bonding. Cold roll bonding of Al/Al and Cu/Cu as well as the heterogeneous combination Al/Cu were investigated with a focus on the minimum degree of deformation required to form a solid bond. By applying XHV-adequate conditions, the minimum degree of deformation for the formation of a solid bond could be reduced by up to 35%. Furthermore, it was evident that the adhesion behaviour changed during bond formation in XHV-adequate conditions.

Novel aluminum-copper compound castings devoid of oxide layers at the interface between the joining partners were developed in order to increase the thermal conductivity of the hybrid component. Due to the natural oxide layers of both aluminum and copper, metallurgical bonds between such bi-metal castings cannot be easily achieved in conventional processes. However, in an atmosphere comparable to extreme high vacuum created by using silane-doped inert gas, metallurgical bonds between the active surfaces of both aluminum and copper can be realized without additional coatings or fluxes. An intermetallic was created between aluminum and copper. Thus, very high thermal conductivities could be obtained for these hybrid castings, exceeding those of conventionally joined samples considerably. The intermetallic phase seams emerging between the joining partners were investigated using scanning electron microscopy and X-ray diffraction. The reduction of casting temperatures resulted in narrower intermetallic phase seams and these in turn in a much lower contact resistance between the two joining partners. This effect can be utilized for increasing the heat transfer capabilities of compound casting components employed for cooling heat sources such as high-power light-emitting diodes.

The production processes of the metalworking industry are usually carried out in the presence of oxygen. Par ticularly due to surface oxidation on tools and parts during production under normal atmosphere, high wear is observed in tribological systems. The focus of these investigations is the question to what extent the ambient atmosphere has an influence on the tribological system. For this purpose, the identification and characterization of wear mechanisms in an oxygen-free atmosphere is of high relevance. To analyse the influence of the ambi ent atmosphere on the tribological properties of titanium, ball-on-disc investigations are carried out on a univer sal tribometer (UMT) in an air, argon and silane-anodized atmosphere. By suppressing the oxidation under ex clusion of oxygen, a reduction of the tribochemical wear could be shown, which is accompanied by a reduction of the wear volume by a Factor of 4.5. However, due to the adhesion of both friction partners, which already occurs at low temperatures, caused by the omission of the friction-reducing cover layers, the friction coefficient increased. In addition, novel alloy formations at the interfaces were detected and analysed.

One possibility to increase the interface strength of cold roll bonded materials is the application of a thin intermediate layer. In the present study, a tin coating was employed to strengthen the interface formed between cold roll bonded steel sheets, and the impact of subsequent heat treatment on the resulting bonding strength was investigated. To increase the bond strength by diffusion, the tin-coated steel bonds underwent heat post-treatment between temperatures of 150 °C and 300 °C for different dwell times. The results demonstrate that the use of tin as an active intermediate layer increases the bond area established. Moreover, the thin tin coating results in the formation of an active intermediate layer that directly takes part in the joining process by establishing a reactive link between the two substrates. A subsequent heat treatment further affects the bond strength by diffusion of tin at the interface.