In order to develop high strength metal–matrix composites with acceptable ductility, bulk nanostructured aluminum–matrix composites reinforced with graphene nanoflakes were fabricated by cryomilling and hot extrusion processes. Microstructure and mechanical properties were characterized and determined using transmission electron microscopy, electron dispersion spectroscopy, as well as static tensile tests. The results show that, with an addition of only 0.5wt% graphene nanoflakes, the bulk nanostructured aluminum/graphene composite exhibited increased strength and unsubdued ductility over pure aluminum. Besides, the mechanical properties of the composites with higher content of graphene nanoflakes were also measured and investigated. Above 1.0wt% of graphene nanoflakes, however, this strengthening effect sharply dropped due to the clustering of graphene nanoflakes. Furthermore, the optimal addition of graphene nanoflakes into the nanocrystalline aluminum matrix was calculated and discussed.

Creep age forming (CAF) is an effective technology to manufacture large aircraft panel components of aluminum alloys. CAF has attracted much attention in the past few years, however, the evolution of microstructure and performances during the process remains unclear.In the present work, microstructure evolution and relevant variation of tensile property of the Al-Cu-Mg alloy during CAF process was investigated by combination of TEM, tensile tests and electrical conductivity tests. It was found that the presence of external stress had performed a slight but clear influence on the precipitations and the related age-hardening behavior. The precipitation process of S phases was accelerated. Compared with stress-free-aged ones, stress-aged samples achieved peak strength within shorter ageing time and they also exhibited higher yield strength at under-aged condition, but lower yield strength at over-aged stage. The electrical conductivity of stress-aged samples was higher than those of stress-free-aged ones. The effect of stress on microstructure and tensile property of Al alloy was discussed.

The crystal structure and electronic properties of LixMnPO4 (x=0, 0.5, 1) as cathode material of rechargeable lithium ion batteries, are studied through first principles calculations. Results show that the large volume change from LiMnPO4 to MnPO4 is mainly the result of Jahn–Teller (JT) distortion around Mn3+ ions in MnPO4. The JT effect also plays an important role in Li0.5MnPO4 compound. When the valence states of Mn ion change from bivalent to trivalent, Mn atom loses an electron which is initially localized at the Mn-3d(x2−y2) orbital. The results also show that the band gap of Li0.5MnPO4 is the smallest compared to LiMnPO4 and MnPO4.

Hot deformation of 7050 aluminium alloy with coarse elongated grains has been investigated by tensile tests conducted at 340 and 460°C and the strain rate of 1˙0 × 10–4–1˙0 × 10–1 s–1. When the 7050 aluminium alloy was conducted at 460°C and 1˙0 × 10–2 s–1, the maximum elongation of 273% is achieved and large plastic deformation was carried out at an almost constant stress. The microstructure evolution under the deformation condition is characterised using OM, SEM, EBSD and TEM in detail. The results show that the microstructure evolution is realised by continuous dynamic recrystallisation in coarse grains. The increase in misorientation is proportional to the increase in the true strain, and the k value, the increasing rate of average misorientation angle, is 15˙7°. The primary hot deformation mechanisms of the 7050 aluminium alloy are localised grain boundary sliding and dislocation gliding, which can increase the grain boundary misorientation continuously.

Combined extrusion experiment (including direct and indirect extrusion) at 440 for large amount of deformation was carried out with the solution treated AA7050 aluminum alloy. Qualitative description and quantitative characterization were conducted employing electron backscattered diffraction (EBSD) technique on the microstructure of typical regions with different filler contents. These characteristic regions were filled at the following stages: ahead of filling (AF), beginning of filling (BF), mid stage of filling (MF) and the end of filling (EF). EBSD results showed that recrystallization fraction during direct extrusion were 8.3%, 13.5%, 9.3% and 11.2%, for AF, BF, MF and EF, respectively. Recrystallization fraction during indirect extrusion were 15.5%, 9.1% 5.2% and 9.9%，for AF, BF, MF and EF, respectively. It shows that the mode and the amount of deformation played an important role in DRX. DRX grains were formed continuously during direct extrusion, while during indirect extrusion, fewer DRX grains generated, and only originally generated DRX grains grew larger gradually.

Through-thickness texture gradient in AA 7055 aluminum alloy rolled plate has been investigated using the electron back-scattered diffraction (EBSD) technique. Quantitative analyses of texture in five layers from the surface to the center of the plate were performed. A pronounced texture variation through the plate thickness was found. In the center layer, a typical β fiber texture running from {112} <111> orientation through {123} <634> orientation to {011} <211> orientation was found. Near the surface, in contrast, shear type textures including {001} <110> orientation, {112} <110> orientation and {111} <110> orientation were dominating. In particularly, when the shear type textures reached the maximum in both intensity and content, the β fiber became minimums.

The texture evolution of polycrystalline AA 7055 aluminum alloy during rolling about 15% and 50% at room temperature and cryogenic temperature has been investigated by electron back-scattered diffraction (EBSD). With increasing the rolling reduction, the intensities of the components of the β fiber increase at both rolling temperature and simultaneously, the shear textures disappear gradually. The lattice rotation paths from the {001}<110> orientation to β fiber was discussed.

Through-thickness microstructure, texture and mechanical property gradients in the longitudinal section of AA 7055 rolled plate have been investigated using electron back-scattered diffraction (EBSD) technique. Quantitative analysis of the microstructure and texture through the plate thickness was conducted. It was found that the microstructure and texture are obviously non-homogeneous through the plate thickness. From center to surface, more equiaxed grains are observed. As expected, the degree of recrystallization increases with increasing the S value. The grains in the center layer exhibited preferential orientations while the most grains near the surface presented a random one. The strength of each observed layer has also been tested.

The superplastic deformation and microstructure evolution of solid solution treated 7050 aluminum alloy has been investigated. Tensile were conducted at 420 and 460 °C with the strain rate of 1.0×10-4 ~ 1.0×10-1 s-1, and the deformed samples were characterized using optical microscopy, scanning electron microscopy and electron backscatter diffraction. The results show that the solid solution treated 7050 aluminum alloy gained the maximum elongation of 273% at 460 °C with the strain rate of 1.0×10-2. At the deformation condition, a large part of plastic deformation was completed at an invariable stress. The microstructure transformed from coarse grains to a bimodal microstructure and then to a nearly uniform fine microstructure and the dynamic restoration process is from dynamic recrystallization plus dynamic recovery to dynamic recrystallization with the increasing deform strain during superplastic deformation.

The electron trajectories in the axial emission gauge (AE gauge) were studied using the electronic computer, and the distribution of the electric field in the gauge is improved. The lengths of the electron trajectories passing through the effective space for ionization are elongated, and a large part of the electrons are collected at last by the newly considered ‘electron collector’. The X-ray generated on this electron collector is effectively screened by a small shielding cylinder surroundig the ion collector. In the prelimanary experiment, it was confirmed that more than 70% of the electrons were collected by the electron collector, and the sensitivity S of this gauge was higher than 1 Pa−1.

Upon the basis of the axial-emission ionization gauge (AEG)1, a new axial-emission bent beam gauge (AEBBG) has been developed by adding small deflecting electrodes between the grid and the front of the collector. Due to the deflection of the residual photo-current to the ion collector, the pressure limit of the AEBBG is less than ⩽ 10−12 Pa at Ie = 2mA, Vg = 500 V, Vf = 300 V, Vd = −320 V, Vc = 0 and Vs = 500 V. In comparison with Helmer's bent beam gauge, the AEBBG has the advantage of a high sensitivity (0.25 Pa−1 for N2) and simple electrode construction allowing easier degassing and a lower filament temperature. All these make the AEBBG more suitable for the measurement of uhv and xhv. Furthermore, the upper limit can be extended to 2.7 × 10−2 Pa when Ie is decreased to 0.2 mA.

An axial-emission self-modulating ultra-high vacuum ion gauge (AESMG) based on developments of the axial-emission ion gauge (AEG) is described. The self-modulation technique used in AESMG operates by means of changing the potential of the collector. The AESMG has some advantages such as rather high sensitivity, simplicity of structure and the modulating coefficient of soft X-ray photocurrent is almost equal to unity. The limiting measurable pressure of AESMG is about 2 × 10 −12 torr.