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Extensive grape pomace from red-winemaking may seriously pollute the environment and cause the waste of resources. Cellulose after fermentation in grape pomace is suitable as the source of extract outstanding cellulose nanocrystals (CNCs). Herein, CNCs were successfully extracted from grape pomace with an eco-friendly and facile deep eutectic solvent (DES). The green DES with the composition of lactic acid/choline chloride (the molar ratio was 2:1), were used to fabricate CNCs. Importantly, the obtained CNCs as a robust nanocomposite can be successfully utilized to prepare the self-healing nanocomposite hydrogels. After added of Fe(III) and borax, the excellent self-healing performance of the guar gum-based hydrogels were achieved by the reversible noncovalent bonding interaction. Specifically, the hydrogels showed good mechanical properties (the stress was about 0.95 MPa, the strain was about 170%) and self-healing ability (the self-healing efficiency was about 90.0%). These biologically self-healing nanocomposite hydrogels can greatly broaden the recycling and utilization of grape pomace.

Nowadays, hydrogels as flexible materials have attracted considerable attention in frontier fields such as wearable electronic devices, soft actuators and robotics. However, water-based hydrogels inevitably freeze at subzero temperatures and suffer damage from contact with objects, which greatly reduce their service life and practical value. Herein, nanocomposite hydrogels with self-healing performance at subzero temperatures were proposed by introducing binary water-glycerol continuous phase and dual self-healing interactions. The binary solvents were emphasized in preventing the formation of ice crystals, enhancing flexible and self-healing abilities of hydrogels in subzero environment. Linseed oil as healing agent was effectively loaded in Pickering droplets by cellulose nanocrystals. Owing to non-covalent bonding and external healing agent, the obtained hydrogels showed improved mechanical properties and self-healing abilities. Particularly, after incorporating Pickering droplets, the rupture stress of nanocomposite hydrogels was 0.24 MPa, the rupture strain was 1900% and the healing efficiency could be up to 80.1% for 12 h at − 20 °C. Therefore, the obtained hydrogels with frost resistance, stretchability and self-healing properties should have broader potential applications, especially in subzero environment.

The NiTiHf-Nb alloy exhibits good workability as well as high-temperature shape memory property. In this work, effects of cooling rate on martensitic transformation behavior and shape memory property for Ni-rich (Ni50.1Ti34.9Hf15)85Nb15 alloy were investigated. For comparison, the martensitic transformation behavior and shape memory property of Ni50.1Ti34.9Hf15 alloy were also investigated. As the cooling rate decreased from water cooling to furnace cooling after solution treatment, the martensitic transformation temperatures (TTs) of (Ni50.1Ti34.9Hf15)85Nb15 alloy decreased gradually, whereas the decrease was not obvious for Ni50.1Ti34.9Hf15 alloy. The increased valence electron concentration (cv) should account for the decrease in TTs of (Ni50.1Ti34.9Hf15)85Nb15 alloy. The shape memory effect strain increased with the decrease in the cooling rate for both two alloys, and the largest shape memory effect strain of 2.6% can be obtained in furnace-cooled (Ni50.1Ti34.9Hf15)85Nb15 alloy. This enhancement in the shape memory property should be ascribed to the precipitation of H-phase in furnace-cooled (Ni50.1Ti34.9Hf15)85Nb15 alloy.

Recently years, hydrogels have received increased attention due to their promising applications in wound dressing, tissue engineering, biosensors and human-machine interfaces. However, designing hydrogels with good mechanical strength and self-healing ability remains a challenge. As a novel strategy, functional Janus nanosheets (JNs) were used as reinforcement to develop self-healing nanocomposite hydrogels. Herein, the silica Janus hollow spheres were prepared by a sol-gel process, modified with poly(2-(acryloyloxy)ethyl ferrocenecarboxylate)(PMAEFc)/polydopamine(PDA) to the internal/external surfaces and then crushed to fabricate the SiO2@PMAEFc/PDA JNs. The SiO2@PMAEFc/PDA JNs were then used as robust reinforcement to design self-healing nanocomposite hydrogels. Based on multiple effects of metal–coordination and host–guest interactions, the mechanical strengths and self-healing properties of hydrogels were both enhanced. Specially, after introducing JNs, the rupture stress of hydrogels increased from 1.27 MPa to 2.23 MPa, and the self-healing efficiency improved from 66.7% to 92.4%. These results demonstrate that JNs can be used as robust reinforcement to fabricate self-healing nanocomposite hydrogels, which enriches the design of self-healing hydrogels and broadens the application prospects of Janus nanomaterials.

The evolution of phase composition and microstructure such as grain size, dislocation and crystallographic texture in austenite-martensite duplex Ni47Ti44Nb9 rolled sheets during the annealing was systematically investigated. The influence of annealing temperature on shape memory effect was also examined. The strong {001} fiber texture tested in as-rolled sheets is identified as a wrong result, which is mistakenly introduced by X-ray Diffractometer, due to the interference of martensite. Different annealing temperatures result in variation of phase composition and microstructure. For instance, in the case of 600 °C, the phase fraction of austenite increases and the dislocations develop to form tiny sub-grains due to reverse martensitic phase transformation and recovery. The texture of NiTi austenite mainly concentrates on {111}〈110〉. In the case of 950 °C, the sub-grains develop to trigger recrystallization, resulting in larger grains and decreasing of dislocations and {111}〈110〉 texture intensity. In addition, the sheets annealed at 600 °C possess higher recoverability than those of 950 °C, which can be attributed to the combined role of grain size, dislocation and crystallographic texture.

The hot working behavior of Mg-Gd-Y-Nb-Zr alloy was investigated using constitutive model and hot processing maps in this work. Isothermal compression tests were conducted with temperature and strain rate range of 703–773 K and 0.01–5 s −1 , respectively. Improved Arrhenius-type equation incorporated with strain compensations was used to predict flow behavior of the alloy, and the predictability was evaluated using correlation coefficient, root mean square error and absolute relative error. Processing maps were constructed at different strains for Mg-Gd-Y-Nb-Zr alloy based on dynamic materials model. The processing maps are divided into three domains and the corresponding microstructure evolutions are referred to the forming of straight grain boundaries, twinning, dynamic recrystallization and grain growth. Instability occurred mainly at the strain rate range of 0.3s −1 –0.5s −1 . The optimum processing domain is mainly at the temperature range of 703–765 K with the strain rate range of 0.01–0.1 s −1 .

This work aims to clarify the influence of texture type and intensity on the shape memory effect (SME) in NiTiNb shape memory alloy (SMA) pipe joints, especially revealing the causes for the anisotropy of SME via texture changes. Three NiTiNb rods with different intensities of the {111} texture were fabricated, and their microstructures, crystalline orientation distribution functions and inverse pole figures were obtained by X-ray diffraction and electron backscatter diffraction measurements. Simultaneously, the SME was characterized by inner-diameter recoverability of the corresponding pipe joints. For a given intensity of the {111} texture, the SME of the NiTiNb pipe joints strongly depended on the expansion direction due to {111} orientation-induced anisotropy of SME. In addition, both the SME and anisotropy of NiTiNb pipe joints increased with the increased intensity of the {111} texture. Therefore, a suitable expansion direction and strong texture intensity should be considered for high SME in NiTiNb pipe joints.