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There is an increasingly urgent need of lightweight components in aerospace industry, among which aluminum (Al) alloys have been the optimal materials of choice for aircraft structural parts since being used in the Junkers F.13 aircraft in the 1920s. Compared to other metal materials, Al alloys have a lower density, and the use of Al alloys reduces the total weight of the aircraft and improves fuel efficiency and load capacity. Meanwhile, the strength and hardness of Al alloys with alloying and heat treatment can be significantly enhanced for uses in high loads and vibration environments. Furthermore, in the harsh aerospace environment, aircraft may receive various climatic conditions and chemical corrosion. Due to good corrosion and fatigue resistance, Al alloys demonstrate excellent performance under these conditions, ensuring the long–term service life of aircraft. In addition, Al alloys have good recyclability, and they can be recycled to reduce resource consumption and environmental load, in line with the principle of sustainable development. In recent years, although composites have been widely used in aerospace, high–strength Al alloys are still in an indispensable position. Therefore, this article reviews the progress and applications of Al alloys commonly used in aerospace. The common strengthening methods and advanced manufacturing and processing technologies of Al alloy are also discussed, which can provide references for the development of advanced high–performance aviation Al alloys in the future.

In this study, different contents (0.0, 0.1, 0.2, and 0.4 wt.%) of Zr55Cu30Al10Ni5 amorphous alloys (Zr-AA) are used to manipulate hypereutectic Al-Si alloys. The edge-to-edge model shows that there is a perfect lattice matching between the crystallized phases and α-Al and Si phases. The thermal analysis of solidification behavior of hypereutectic Al-Si alloys unmanipulated and manipulated by Zr-AA, indicates that the addition of Zr-AA greatly promotes the nucleation of primary Si and significantly accelerates the process of eutectic reaction. When manipulated by the optimal content of 0.2 wt.% Zr-AA, the sizes of α-Al dendrites and primary Si decrease from 212.46 μm and 19.24 μm to 143.39 μm and 16.47 μm, respectively. The eutectic Si changes from needle-like to rod-like and exhibits a mean size decrease from 20.21 μm to 11.69 μm. Meanwhile, alloys exhibit ultimate tensile strength of 362 MPa and fraction strain of 2.21% after 0.2 wt.% Zr-AA manipulation, which are 23% and 37% higher than those of the unmanipulated alloy (295 MPa and 1.61%). The strengthening mechanisms of hypereutectic Al-Si alloys manipulated by in situ nanocrystals crystallized in the melt are mainly attributed to the fine grain strengthening effect and precipitation strengthening effect. The increase in plasticity is due to the refinement and morphology improvement of Si phases.

In this study, the thermal stability of Ni–Nb–Ti metallic glasses was investigated under isothermal and non-isothermal conditions. The effectiveness of NiTi phases, one of the nanosized crystallized phases, as grain refiners for Al–Cu alloys was also investigated from a crystallographic point of view using the edge-to-edge matching (E2EM) model. Thermal analysis showed that NiTi phases promote solidification of α-Al, and these nanocrystalline phases also promote an Al–Cu eutectic reaction and inhibit the growth of eutectic phases. A significant refining effect of α-Al grains from 402.7 μm to 69.1 μm was achieved with 0.05 wt.% nanocrystalline phases. Simultaneously, values for yield strength, ultimate tensile strength and fracture strain of inoculated Al–Cu alloys were increased by 18%, 13% and 78% to 363.2 MPa, 534.3 MPa and 11.92%, respectively, when compared with those of uninoculated Al–Cu alloys. Strengthening mechanisms of Al–Cu alloys manipulated by the nanocrystalline phases are grain boundary strengthening and precipitation strengthening.

Abstract: Well-defined PNNCN pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their PN3P analogs. These reactions proceed under mild and base-free conditions via protonation–deprotonation of the ‘NH’ group in the aromatization–dearomatization process. [Copyright &y& Elsevier]

Dehydrogenative homocoupling of primary alcohols to formestersand coupling of amines to form imines was accomplished using a classof novel pincer ruthenium complexes. The reactivities of the rutheniumpincer complexes for the direct coupling of amines to form imineswere enhanced by introducing an imine arm to the pincer ligand. Selectiveoxidation of benzylamines to imines was achieved using aniline derivativesas the substrate and solvent. [ABSTRACT FROM AUTHOR]

Abstract: A dearomatized complex [RuH(PN3P)(CO)] (PN3P N, N′-bis(di-tert-butylphosphino)-2,6-diaminopyridine) (3) was prepared by reaction of the aromatic complex [RuH(Cl)(PN3P)(CO)] (2) with t-BuOK in THF. Further treatment of 3 with formic acid led to the formation of a rearomatized complex (4). These new complexes were fully characterized and the molecular structure of complex 4 was further confirmed by X-ray crystallography. In complex 4, a distorted square-pyramidal geometry around the ruthenium center was observed, with the CO ligand trans to the pyridinic nitrogen atom and the hydride located in the apical position. The dearomatized complex 3 displays efficient catalytic activity for hydrogen transfer of ketones in isopropanol. [Copyright &y& Elsevier]

A series of novel titanium(IV) complexes combining a phosphine oxide‐bridged bisphenolato ligand TiCl2{2,2′‐OP‐R3 (4‐R2‐6‐R1‐C6H2O)2}(THF) (6a: R1 = tBu, R2 = H, R3 = Ph; 6b: R1 = Ph, R2 = H, R3 = Ph; 6c: R1 = R2 = tBu, R3 = Ph; 6d: R1 = R2 = cumyl, R3 = Ph; 6e: R1 = tBu, R2 = H, R3 = PhF5) were prepared by the reaction of corresponding bisphenolato ligands with TiCl4 in THF. X‐ray analysis reveals that complex 6a adopts distorted octahedral geometry around the titanium center. These catalysts were performed for ethylene polymerization in the presence of modified methyaluminoxane (MMAO). The effects of reaction parameters on ethylene polymerization behaviors, such as cocatalyst concentration, polymerization temperature, and reaction time were studied in detail. In general, these new complexes exhibited high catalytic activity, good temperature tolerance, and long lifetime for ethylene polymerization. The resulting polymers possess high molecular weight, unimodal distribution, and linear structure. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7062–7073, 2008 [ABSTRACT FROM AUTHOR]

The design of novel pincer ligands is described. [ABSTRACT FROM AUTHOR]