The present study was focused on the relationship between an α platelet microstructure and the properties of TC21 alloy, and the tensile deformation process was revealed by in situ observation. To obtain the α platelet microstructures, the samples were administered a solution treatment (1000 °C for 15 min) and then cooled to room temperature by different cooling methods (furnace cooling (FC), open-door furnace cooling (OFC), air cooling (AC), and water quench (WQ), corresponding to an increased cooling rate). It is found that α platelets become thinner and colonies become narrower with the increase in cooling rate. The formation of the platelet microstructure is based on the preferred Burgers orientation relationship of {110}_β//{0001}_α and _β//_α. The α platelets orientation changes with the cooling rate. These differences in α platelets thickness and orientation result in the excellent ductility of the sample with thick platelets and the high strength of the samples with thin platelets. During the in situ tensile deformation process, the crack propagation path is deflected in the presence of grain boundaries, α platelets, and α colonies with different orientations. The fracture of the sample with thick α platelets shows better ductility compared to those with thin α platelets.

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivative (PN-DOPO) combined with aluminium phosphates-coated sepiolite (Sep@AlPO₄) was used to improve the flame retardance, thermal stability and mechanical performances of poly (ethylene oxide) (PEO)/poly (butylene adipate-co-terephthalate) (PBAT) blends. The synergistic effects of PN-DOPO and Sep@AlPO₄ on flame-retarded PEO/PBAT composites were systematically discussed. Results indicated that introducing 5 wt% Sep@AlPO₄ with 10 wt% PN-DOPO into PEO/PBAT achieved a V-1 rating for the UL-94 test and increased the limiting oxygen index value to 23.7%. Moreover, the peak heat release rate (p-HRR), average HRR and total heat release values of PEO/PBAT/PN10%/Sep5% composites decreased by 35.6%, 11.0% and 23.0% compared with those of PEO/PBAT, respectively. Thermogravimetric analysis (TGA) results confirmed that PN-DOPO/Sep@AlPO₄ enhanced the initial thermal stability and char yield of PEO/PBAT matrix, and TGA/Fourier transform infrared spectrometry results revealed that the composites exhibited the characteristic absorption peaks of phosphorous-containing groups and an increase in gas-phase volatiles during thermal degradation. The morphological structures of the residues indicated that PN-DOPO and Sep@AlPO₄ mixtures produced a more dense and continuous char layer on the composite surface during burning. Rheological behaviour revealed that higher complex viscosity and modulus values of PEO/PBAT/PN-DOPO/Sep@AlPO₄ sample could also promote the crosslinking network structure of condensed phases during combustion. Furthermore, the PEO/PBAT/PN-DOPO/Sep@AlPO₄ composites exhibited superior elongation at break and flexural performance than the PEO/PBAT system. All results demonstrated that the PEO/PBAT system modified with PN-DOPO/Sep@AlPO₄ showed remarkable flame retardance, and improved thermal stability and mechanical properties, indicating its potential application in areas requiring fire safety.

Zinc oxide (ZnO) has been widely employed for the degradation of organic pollutants due to its excellent electron transport properties and abundant active sites. However, it has the drawbacks of narrow light absorption range and rapid photogenerated carrier recombination. Herein, ZnO/GQDs nanocomposites were then prepared to overcome these drawbacks and their photocatalytic degradation performance for Rhodamine B (RhB) was systematically investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) results indicate that ZnO/GQDs exhibit a hexagonal wurtzite structure with regular spherical particles, with the average particle size of 14.10 nm. Photocatalytic tests demonstrate that ZnO/GQDs-0.1 achieves 98% degradation of RhB after 40 min of full-spectrum light irradiation, with a reaction rate constant (0.0628 min-1) approximately four times that of pristine ZnO. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations were employed to elucidate the charge transfer mechanism. Work function calculations by DFT revealed the internal electric field direction at the ZnO/GQDs interface, XPS confirmed the interfacial electron transfer-induced binding energy shifts, and EPR verified the preserved strong redox potential of the photogenerated charges, collectively confirmed that ZnO/GQDs forms an S-scheme heterojunction. Photoluminescence (PL) spectra reveal that ZnO/GQDs-0.1 exhibits the lowest fluorescence intensity, indicating the most effective suppression of photogenerated electron-hole recombination, while EPR results identify superoxide radicals (·O2-) and hydroxyl radicals (·OH) as the key reactive species. This study provides both experimental and theoretical foundations for the construction of ZnO-based S-scheme heterojunctions and the development of efficient photocatalysts.