A regenerated fiber from rennet-treated casein micelles

Casein as the major protein of milk is a promising protein source for biopolymer fibers. Current casein-based fibers are fabricated by dissolving caseins in alkaline media and wet spinning in a coagulation bath containing harsh chemicals. In milk, casein is present in so-called casein micelles (CMs). Based on the rennet-induced aggregation, we developed a process that can be applied for the spinning of micellar casein fibers in a sustainable way without the use of harsh chemicals. Fabricated fibers show a surface with a characteristic microstructure, which can also be detected embedded in a network structure inside the fiber. The fibers are stable under acidic and neutral conditions and decompose in alkaline media down to aggregates with sizes comparable to the characteristic microstructure. The so far reached tensile properties of the micellar fiber are between low and mid double-digit percentage range compared to casein azlons.

Effect of Traverse Speed on the Defect Characteristic, Microstructure, and Mechanical Property of Friction Stir Welded T-Joints of Dissimilar Mg/Al Alloy

The AZ31 B/2024-T4 T-lap-joint was successfully fabricated by friction stir welding (FSW) with different welding parameters. The defect characteristics and metallurgical structure were observed and analyzed using optical microscope (OM) and scanning electron microscopy (SEM). Besides, the effects of defects and welding parameters on mechanical properties were investigated. The results show that an effective metallurgical reaction zone can be formed between Mg and Al (Mg-Al MRZ) and the island structures and lamellar structures appeared in the Mg-Al MRZ. The T-joints without tunnel defects can be obtained and the excellent mechanical properties of the T-joint were achieved using the welding speed of 50 mm/min. The tensile strength along the skin and the stringer was mainly affected by the kiss bonding defects.

XtalCAMP: a comprehensive program for the analysis and visualization of scanning Laue X-ray micro-/nanodiffraction data

XtalCAMP is a software package based on the MATLAB platform, which is suitable for, but not limited to, the analysis and visualization of scanning Laue X-ray micro-/nanodiffraction data. The main objective of the software is to provide complementary functionalities to the Laue indexing software packages used at several synchrotron beamlines. The graphical user interfaces allow the easy analysis of characteristic microstructure features, including real-time intensity mapping for a quick examination of phase, grain and defect distribution, 2D color-coded mapping of microstructural properties from the output of other Laue indexing software, crystal orientation visualization, grain boundary characterization based on orientation/misorientation calculation, principal strain/stress analysis, and strain ellipsoid representation, as well as a series of additional toolkits. As an example, XtalCAMP is applied to the microstructural investigation of a solution-heat-treated Ni-based superalloy manufactured using a laser 3D-printing technique, and a deformed natural quartzite from Val Bregaglia in the Central Alps.

Nanoarchitectonics of Acicular Nanocrystal Assembly and Nanosheet Assembly for Lithium-Ion Batteries

Nanoarchitectonics of metal oxide nanocrystal electrodes were developed for lithium-ion batteries. The electrodes included copper nanoparticles and doped fluorine. For the acicular nanocrystals, charge–discharge reactions progressed at 1.8 V over 100 cycles at 100 and 10 μA. A 15-mmdiameter battery containing acicular nanocrystals showed capacity, coulomb efficiency, and specific capacity, respectively of 20 μAh, 98%, and ~242 mAh/g at 100 μA and 40 μAh, 99%, and 484 mAh/g at 10 μA. The TiO2/SnO2 electrode consisted of a SnO2 sheet-assembled structure with surface layers of anatase TiO2. The TiO2/SnO2 battery operated at 1.3 (100 cycles) and 1.2 (50 cycles) V at 100 and 10 μA, respectively; its capacity, coulomb efficiency, and specific capacity, respectively were 50 μAh, 98%, and 161 mAh/g at 100 μA and 200 μAh, 97–98%, and 643 mAh/g at 10 μA. The characteristic microstructure, chemical composition, and crystal faces of both materials contributed to battery performance.

Aging-induced formation of the nano-sized clustered carbides in the weld metal of Co-based alloy/AISI 410 stainless steel dissimilar welded joint

The microstructure evolution in Co-based alloy/AISI 410 stainless steel dissimilar welded joints by aging at 566 °C for 200, 400, 600, and 800 h was systematically investigated. In particular, the specimen aging treated for 800 h was emphasized in the present study for its nano-sized clustered characteristic microstructure. The results showed that the microstructure of the weld metal (WM) was mainly γ-Co matrix with dendritic morphology. Before aging treatment, the elements Cr and W segregated slightly in the interdendritic regions. Nevertheless, a large amount of nano-sized clustered carbides rich in elements Cr and W precipitated along grain boundaries after aging treatment. The element segregation during solidification and element diffusion under high-temperature condition could trigger the carbide formation. Though the precipitated carbides revealed a negligible influence on the microhardness of weld (∼ 275 HV), yet a stable performance under high-temperature condition was anticipated for this weldment considering the grain boundary strengthening effect of the nano-sized carbides.

Descriptors for High Throughput in Structural Materials Development

The development of novel structural materials with increasing mechanical requirements is a very resource-intense process if conventional methods are used. While there are high-throughput methods for the development of functional materials, this is not the case for structural materials. Their mechanical properties are determined by their microstructure, so that increased sample volumes are needed. Furthermore, new short-time characterization techniques are required for individual samples which do not necessarily measure the desired material properties, but descriptors which can later be mapped on material properties. While universal micro-hardness testing is being commonly used, it is limited in its capability to measure sample volumes which contain a characteristic microstructure. We propose to use alternative and fast deformation techniques for spherical micro-samples in combination with classical characterization techniques such as XRD, DSC or micro magnetic methods, which deliver descriptors for the microstructural state.

Characteristic, Microstructure and Properties of Dense Hydroxyapatite Ceramic from Cockle Shell for Biomaterials

Dense hydroxyapatite ceramic can be fabricated from hydroxyapatite (HA) powder prepared from cockle shells. The shell powder was treated at 900°C and co-precipitated with PO43- in NH4H2PO4 solution at Ca/P ratio of 1.67 in order to synthesize the HA powder. HA discs were formed by a hydraulic press machine and sintered at temperature of 1250°C for 2 h in an electric furnace which helps to dense ceramic. The results from FTIR analysis identified the functional groups of HA powder that has the ion stretching vibration around 3574, 2002 cm-1 for hydroxyl group (OH-), 1451 cm-1 for carbonate (CO32-), and phosphate groups (PO43-) were also observed around 1045 and 560 cm-1 respectively. XRD measurement showed that the ceramic contains hydroxyapatite crystals with β-tricalcium phosphate and calcium oxide as the secondary phase. Morphological evaluations by SEM measurement shows that the HA particles were agglomerated and showed the fractured surface of dense HA when sintered at 1300°C. Grain size ranges from 0.5–1 mm, with an apparent porosity of about 50% of the total area and the pore size ranges from 1–10 mm. Mechanical property measurements show that the dense ceramic contains bending strength of 135 MPa, which is close to the strength of human’s cortical bone (162 MPa).

Characteristic microstructure underlying the fast hydration–dehydration reaction of β-La2(SO4)3: “fine platy joints” with “loose grain boundaries”

The fast hydration/dehydration (water insertion/deinsertion) reaction of β-La2(SO4)3 is expected to be applied to thermochemical heat storage, but its kinetics have not been well understood.