A microstructural informed thermodynamic model is utilized to tailor the pseudoelastic performance of a series of Fe-Mn-Al-Ni shape-memory alloys. Following this approach, the influence of the stability and the amount of the B2-ordered precipitates on the stability of the austenitic state and the pseudoelastic response is revealed. This is assessed by a combination of complementary nanoindentation measurements and incremental-strain tests under compressive loading. Based on these investigations, the applicability of the proposed models for the prediction of shape-memory capabilities of Fe-Mn-Al-Ni alloys is confirmed. Eventually, these thermodynamic considerations enable the guided enhancement of functional properties in this alloy system through the direct design of alloy compositions. The procedure proposed renders a significant advancement in the field of shape-memory alloys.
The effect of the substrate morphology on the microstructure and properties of chemical vapour deposited (CVD) Ti(C,N) coatings was investigated. The coatings were produced in a moderate-temperature process. The substrates were fine-grained and coarse-grained cemented carbides that underwent different treatments – wet blasting, grinding or polishing. The microstructure of the coatings was characterised using X-ray diffraction and scanning electron microscopy with electron backscatter diffraction, and described in terms of the grain size and shape and the preferred orientation of the Ti(C,N) crystallites. These microstructure characteristics were correlated with the surface quality of the substrates, with the residual stresses in the coatings, with the indentation hardness and with the adhesion of the coatings to the substrate. The parameters describing the surface quality of the substrates were the roughness, the size of the tungsten carbide grains, and the kind and density of the defects induced in WC by the surface treatment. Although the Ti(C,N) coatings were deposited in the same deposition process, they consisted of differently large grains having a differently strong preferred orientation {211}. All coatings were under tensile residual stress, but the stress values were affected by the surface treatment. Rough substrates facilitated the growth of large Ti(C,N) grains with a weak {211} texture, and reduced tensile stresses. The Ti(C,N) coatings deposited on smooth substrates were fine-grained, and possessed a pronounced {211} texture.
Abstract AlB 4 O 6 N, Al 0.97 Cr 0.03 B 4 O 6 N, and Al 0.83 Cr 0.17 B 4 O 6 N are the first representatives of the recently established structure‐family of oxonitridoborates containing Al 3+ . These compounds are isotypic to CrB 4 O 6 N and are synthesized in a multi‐anvil press under high‐pressure/high‐temperature conditions of 7.0 GPa/1350 °C. Structural refinement by single‐crystal X‐ray diffraction shows that they crystallize in the space group P 6 3 mc (no. 186) with two formula units per cell. Detailed characterization including high‐temperature X‐ray powder diffraction (HT‐XRD), electron probe microanalysis (EPMA), measurements of second harmonic generation (SHG), hardness, photoluminescence properties, vibrational spectroscopy, and band structure calculations reveal intriguing physicochemical properties that strongly resemble the famous material ruby.
Current challenges related to limited resources, climate change and demographic trends are ubiquitous. An increase in resource efficiency along with the whole product life cycle is of vital importance. Consequently, there is a need to make materials development, product design and production technologies compatible with the principles of sustainability. In this context, research strategies are to be revisited in order to focus on an interdisciplinary, holistic development of competitive products. The resource-efficient solutions for advanced materials, products and processes make a decisive contribution to the adaptation of modern industrial societies towards new ecological and economic standards. Intensive interdisciplinary cooperation is thus becoming more and more important, especially when innovative solutions for new applications are required. At the same time, the trend towards more individual and more various products requires novel strategies for the efficient and flexible development of materials, components and production processes. The research network “Saxon Alliance for MAterial- and Resource-Efficient TechnOlogies (AMARETO)” addresses these challenges by combining and networking the expertise of the project partners located at TU Bergakademie Freiberg (TUBAF), TU Dresden (TUD), Chemnitz University of Technology (TUC) and Fraunhofer Institute for Machine Tools and Forming Technology (Fraunhofer IWU). The AMARETO network was established in 2017. Its central idea was to bundle the expertise of three previous cutting-edge technology clusters:”Functional Structural Design of New High-Performance Materials by Atomic Design and Defect Engineering” (ADDE, Freiberg), “European Centre for Emerging Materials and Processes” (ECEMP, Dresden) and “Energy-Efficient Product and Process Innovations in Production Engineering” (eniPROD, Chemnitz). These clusters were funded as individual projects under the Saxon State Excellence Initiative from 2009 to 2014. The scientific topics of the original clusters were focused on the core competencies of the respective home institution. All clusters achieved outstanding results in basic research and succeeded in transferring these results towards industrial applications. The plausible next step was to utilize the complementary expertise of the partners in a synergetic manner, in particular by taking advantage of their respective specializations in the fields of materials research, design of novel components and development of production processes. This approach not only enables an improved resource-efficiency, but also shortens the time-to-market, reduces product launch risks and finally helps to optimize the value chains. Within the AMARETO network, the development of innovative solutions along the value chain and their implementation into practical applications were carried out in three research fields: efficient materials design (Smart Material), interactive development of components and processes (Smart Design) and resource-efficient production (Smart Production). In order to keep the central topics of the AMARETO project focussed, the research was concentrated on lightweight structures and their processing. The research and development in the field of Smart Materials dealt with (i) modern high-strength magnesium alloys as the base material in lightweight constructions and (ii) novel hard films and duplex coatings with high hardness and good tribological and tribochemical properties as the protective coatings on forming and cutting tools. This research was based on the knowledge of the relationships between the materials' properties (E.g., hardness, toughness, corrosion resistance and wear) and the internal structure of the materials (E.g., beneficial crystal structure defects, which can be systematically manipulated by the manufacturing technology). In the research field Smart Design, development processes for high-performance components were elaborated, in which the three tasks – design, dimensioning and manufacturing – are processed in parallel and interactively. A particular focus lay in the development of numerical models of the manufacturing process and their coupling according to the respective process chain. In addition to meeting functional requirements of the component, this approach also considers the influences and restrictions of individual manufacturing steps within the development process. In particular, this approach generated a deeper understanding of the design of high-performance hybrid lightweight structures made of metal and fiber composites. In turn, this methodology enables the rapid and robust development of complex components and their process chains. The field of Smart Production transferred the developed solutions into a resource-efficient production environment with increased process stability and quality through self-optimizing and intelligent production technology. Here, technologies such as adaptive process control and augmented reality were adopted and enhanced using both machine data and simulation data. This allows the real-time consideration of fluctuating material properties in the production processes. At the same time, the redesign of classic production strategies and processes enables improved flexibility, safety and resilience as well as manufacturing custom-fit products in smaller batches. The interlink of these three research fields represents a decisive step towards sustainable and competitive products as well as towards the innovation of associated processing and manufacturing methods. In recent years, the research network AMARETO demonstrated its ability to achieve fast and significant progress with comprehensive and digitally enhanced understanding and modelling of materials properties, hybrid components, technologies, and process chains. The interdisciplinary network connecting the complementary scientific expertise of the partner institutions has created an innovation core, in which comprehensive technical and technological solutions become possible. The expertise concentrated in the AMARETO consortium supports companies to master the multitude of challenges – such as the increase of material and resource efficiency and the reduction of the time needed for developing or customizing new products. The chosen holistic approach enables the industry to develop materials and components as well as the associated production processes more efficiently. This Special Issue of Engineering Reports offers a collection of scientific contributions that provide a general overview of the outcome of the research network AMARETO. The presented methods and solutions range from efficient material development and optimized design of components and processes up to resource-saving production technologies. We are confident that the insights into the research works of the AMARETO team presented in this Special Issue will provide valuable inspiration for novel developments and the initiation of new collaborations. We wish all readers an informative reading experience. The members of the AMARETO network would like to thank the European Union and the Free State of Saxony for funding the project from 2017 to 2021 via the European Regional Development Fund and the Saxon budget. Furthermore, we thank the members of the AMARETO advisory board for their valuable professional support.
