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We performed rotating bending tests and axial (tension‐compression) load‐increase and constant amplitude high‐cycle fatigue tests in air and Hanks' balanced salt solution (HBSS) on the β‐metastable titanium alloy Ti‐5Al‐5Mo‐5V‐3Cr, processed by laser powder bed fusion (LPBF‐M), solution‐treated and aged, and shot‐peened. Rotating bending loading in air revealed a strong influence of process‐induced flaws on fatigue endurance. Especially in the high‐cycle fatigue range and the transition region, the stochastic distribution of the flaws and flaw sizes led to a high scatter of the number of cycles to failure. The axial load‐increase tests yielded a good fatigue life estimation, with a negligible difference between air and HBSS. The cyclic deformation behavior in HBSS was also strongly influenced by the local microstructure and defect distribution, and, thus, by crack formation and propagation. Plastic deformation and microcrack growth interact, and their relative amount resulted in different progressions of the plastic strain amplitude over the number of cycles for different specimens. Changes in the free corrosion potential and the corrosion current were highly sensitive indicators for fatigue‐induced damage on the rough surfaces, which was correlated to the microscopic examination, fracture surface features, and the fatigue crack development. Highlights: Failure starts at stochastically distributed inner flaws, yielding high scatter of Nf.Cyclic deformation behavior in HBSS depends on local microstructure and flaws.Simultaneous plastic deformation and microcrack growth influence εa,p levels.Microscopy, electrochemistry, and surface fracture illustrate fatigue crack development. [ABSTRACT FROM AUTHOR]

Bioinspired, graded structures with hierarchical porosity, combining high surface area with low density, are attractive for a wide range of applications. Local adaptation of properties makes it possible to fine‐tune their strength and degradation kinetics over time. Production of such structures is, however, still scientifically and technically challenging. A versatile approach for fabricating hierarchical, porous structures from water‐glass (WG), exploiting its inherent foaming ability in conjunction with robocasting, for applications such as, bone‐replacement scaffolds, is presented. The unique processing route that is proposed uses a purely inorganic, mouldable sodium silicate hydrogel based on WG as ink for robocasting, which makes it cost‐effective and highly environmentally friendly. The WG‐based hydrogels can be used in a pure state, and also as carrier systems, e.g., for tricalcium phosphate. Following heat treatment at a relatively low temperature of 450 °C, the robocast parts develop hierarchical porosities. Multi‐microscale porosity is created due to foaming during heating, in addition to the macroscale porosity designed during robocasting. The suggested process opens up a powerful alternative to fabrication routes presently available for hierarchically porous structures. [ABSTRACT FROM AUTHOR]

Open‐cell aluminum foams are gaining importance for the design of lightweight structures and as electrodes in lithium‐ion batteries. AlSi7Mg0.3 foams are produced by a modified investment casting process. By tuning the mold temperature, a change from the usual nearly monocrystalline dendritic to a polycrystalline globular grain structure is achieved. Tension and compression tests on single struts and foam specimens, respectively, are combined with digital image correlation, scanning electron microscopy, and phase contrast‐enhanced microcomputed tomography in a synchrotron facility to correlate the mechanical properties and the failure mechanisms with the microstructure. The "globular" foams exhibit a lower strength and a less pronounced subsequent stress drop than the "dendritic" foams and the deformation mechanism changes from shear band‐dominated failure to a layer‐by‐layer collapse, because of the lower strength and higher ductility of the "globular" struts. The "dendritic" struts have a more homogeneous microstructure, while the "globular" struts often contain silicon agglomerates in their central region. Accordingly, the latter struts exhibit a higher degree of scatter for the fracture strain. Thus, the arrangement of the silicon particles and the eutectic determines the mechanical properties on the strut level and thereby the failure behavior on the foam level. [ABSTRACT FROM AUTHOR]

Ice‐templating, a versatile manufacturing process, is widely utilized to create porous materials by freezing aqueous solutions. Notably, this technique is material independent, allowing for the fabrication of microstructured bulk or sheet materials of ceramic, glass, metal, polymer, and composite materials. Herein, the influence of freeze‐cast zinc electrodes on zinc–air batteries is investigated. The analysis includes the charge and discharge cycling behavior of pure powder, gel matrix, and sintered freeze‐cast zinc electrodes, complemented by the study of the distribution of relaxation times. Remarkably, the best cycling performance is achieved with the combination of a gel electrolyte and a freeze‐cast zinc electrode, highlighting the potential significance of this microstructure–electrolyte pairing for enhancing the performance of zinc–air batteries. [ABSTRACT FROM AUTHOR]

Humanity is often fascinated by structures and materials developed by Nature. While structural materials such as wood have been widely studied, the structural and mechanical properties of fungi are still largely unknown. One of the structurally interesting fungi is the polypore Fomes fomentarius. The present study deals with the investigation of the light but robust fruiting body of F. fomentarius. The four segments of the fruiting body (crust, trama, hymenium, and mycelial core) were examined. The comprehensive analysis included structural, chemical, and mechanical characterization with particular attention to cell wall composition, such as chitin/chitosan and glucan content, degree of deacetylation, and distribution of trace elements. The hymenium exhibited the best mechanical properties even though having the highest porosity. Our results suggest that this outstanding strength is due to the high proportion of skeletal hyphae and the highest chitin/chitosan content in the cell wall, next to its honeycomb structure. In addition, an increased calcium content was found in the hymenium and crust, and the presence of calcium oxalate crystals was confirmed by SEM-EDX. Interestingly, layers with different densities as well as layers of varying calcium and potassium depletion were found in the crust. Our results show the importance of considering the different structural and compositional characteristics of the segments when developing fungal-inspired materials and products. Moreover, the porous yet robust structure of hymenium is a promising blueprint for the development of advanced smart materials. [ABSTRACT FROM AUTHOR]

Improving the ductile deformation behavior of Mg-SiC nanocomposites without compromising strength is critical to enhancing their mechanical properties. Mg-SiC nanocomposites are produced through mechanical milling, cold isostatic pressing, sintering, and hot extrusion processes. This study investigates the uniaxial stress–strain response and deformation behavior of the Mg-SiC nanocomposite compared to pure Mg samples with and without the milling process. The deformation behavior was investigated by two-dimensional (2D) digital image correlation (DIC) at two macroscopic and microscopic scales, employing light micrographs and in situ loading samples, respectively, in the scanning electron microscope. Compared to the pure Mg samples, the mechanical test results demonstrated a significant improvement in strength (80 MPa) and fracture strain (23.5%) of the Mg-SiC nanocomposite. The three-dimensional (3D) representative volume element (RVE) model revealed the particle dispersion effect on the mechanical properties of the nanocomposite. The RVE results demonstrate ductile deformation behavior in the sample with homogenous dispersion of SiC particles compared with the heterogeneous dispersion of SiC particles in Mg-SiC nanocomposite. The results demonstrated a good agreement between DIC and RVE predictions for Mg-SiC nanocomposites across macro- and microscales. [ABSTRACT FROM AUTHOR]