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The Al–Cu–Mg–Ag single crystal is prepared to study its precipitation behavior during aging under elevated compression stresses. Transmission electron microscopy (TEM), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and hardness test are used for this investigation. The results show that a compression stress of 50 MPa leads to more uniform length distribution but slightly lower number density of Ω-phase in the stress-aging sample, as compared to that of the stress-free aging sample. When a higher compressive stress of 200 MPa is applied, the number density of Ω-phase is significantly decreased while a large number density of θ’-phase are precipitated along the dislocation lines introduced by the applied stress. Furthermore, the stress-orientating effect on Ω precipitation can not be observed in Al–Cu–Mg–Ag single crystal during stress aging even under the compressive stress of 200 MPa loading along the [ 2 ¯ 15 ] Al direction. This result signifies that the applied stress magnitude is not the only critical factor in determining whether the stress-orienting effect of Ω-phase can be generated, as this effect may be also associated with the loading orientation during stress aging. [ABSTRACT FROM AUTHOR]

The influence of high strain rate on the precipitate microstructure in impacted aluminum alloy was revealed by transmission electron microscopy. The estimated aspect ratio and the area fraction of θ′ precipitate in impacted aluminum alloy specimens were not dramatically changed until impact testing at 5730s−1 or higher at ambient temperature although the hardness of specimens impacted at 667–7050s−1 was decreased. High strain rates are thus a simple way to lower the transformation temperature of θ′ phase in impacted aluminum alloy. [Copyright &y& Elsevier]

Abstract: One dimensional bifunctional magnetic-photocatalytic CNTs/Fe3O4–ZnO nanohybrids were synthesized by one-pot polyol sequential process. The as synthesized products were characterized by X-ray diffraction, Fourier transform infrared spectrometer, transmission electronic microscope, energy dispersive spectrometer, physical properties measurement system and UV–Vis absorption spectroscopy. The results exhibit the ZnO forms heterogenerously on the surface of CNTs/Fe3O4 and the nanohybrids display superparamagnetic behavior at room temperature. Photocatalytic studies verify the as-prepared sample have high photocatalytic activity toward the photodegradation of methyl orange in solution. In addition, the photocatalyst can be recycled using magnetic field and maintain high photocatalytic activity. [Copyright &y& Elsevier]

Abstract: PX-phase PbTiO3 (PT) nanowires were synthesized by microwave-hydrothermal process, and their microstructures were characterized by electron microscopy. The PX-phase PT nanowires exhibit acicular morphology with diameter sizes of 20–80nm and length over 1µm. They tend to grow into a regular structure with parallel arrangement along their long axis in the [001] direction. Selected area electron diffraction patterns demonstrate the PX-phase PT nanowires with a 3-fold modulated periodicity along the [110] direction and a 4-fold modulated periodicity in the [001] direction. These results were also confirmed by the high-resolution transmission electron microscopy images. [Copyright &y& Elsevier]

Abstract: Compositionally-graded (Ba1−x Sr x )TiO3 thin films (x varying from 0 to 0.25) were epitaxially grown by pulsed-laser deposition on (100)MgO single-crystal substrates with a conductive La0.5Sr0.5CoO3 layer as bottom electrode. The crystallinity and epitaxial growth behavior of the graded BST films were investigated by X-ray diffraction and transmission electron microscopy. The results show that the graded films are (100)-oriented with an orientation relationship of (100)[010]BST//(100)[010]MgO. Cross-sectional TEM images show that graded BST films grow with a columnar structure and a surface roughness of 10nm. From planar TEM images granular and/or polyhedral shaped grains are observed with an average grain size of 65nm. At room temperature, the dielectric constant and dielectric loss at 10kHz for the graded film were 953 and 0.0103, respectively. A broad and flat profile of the dielectric constant versus temperature was demonstrated in the graded film. This was attributed to the presence of the compositional and/or residual strain gradients in the epitaxial compositionally-graded films. With such a graded structure, it is possible to build dielectric thin film capacitors with almost negligible temperature dependence of the capacitance, thereby operating without the need for controlling the environmental temperatures. [Copyright &y& Elsevier]