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The effect of SiC particle size (300, 600 and 1200 mesh) on the properties of 15 wt% SiC particles reinforced AlSi10Mg matrix composites fabricated by laser powder bed fusion (LPBF) was investigated. The results showed that the laser absorptivity of blended powder increased as the SiC particle size decreased, which was useful to improve the densification of the LPBFed composites. The highest relative density of 98.9% was obtained at 1200 mesh of SiC particle. The amount of the interfacial reaction products, including Al4SiC4 and Si, was increased with reducing the SiC particle size. For all type of the composites, SiC particles had a good wettability with the aluminum matrix owing to the high temperature and the interfacial reaction during the LPBF process. The mechanical properties were significantly improved by decreasing the SiC particles size. The microhardness of 316.1 HV0.2 and the ultimate compressive strength of 764.1 MPa were achieved using SiC particle having 1200 mesh size. The existence of the pores in the aluminum matrix and the SiC particle's cracking were the primary reasons for the failure of the composites. Furthermore, large SiC particles were more easily cracked. When the SiC particle size decreased from 300 mesh to 1200 mesh, the average coefficient of friction (COF) distinctly reduced from 0.45 to 0.18 and wear rate decreased from 9.09 to 2.02 × 10−4 mm3N−1m−1, respectively. The abrasive and adhesive wear were the dominant wear mechanism of the LPBFed composites with 300 mesh of SiC particle. However, as the SiC particle decreased to 1200 mesh, the main wear mechanism was transferred to the delamination and abrasive mechanism. These results are contributed to understanding the characteristics of LPBFed SiCp/AlSi10Mg composites.

In this paper, high quality GaAs films on Ge (0 0 1) substrates with 9° offcut toward the (1 1 1) plane were grown by metal organic chemical vapor deposition (MOCVD) through adopting the Al 0.3 Ga 0.7 As interlayers with pulsed atomic layer epitaxy (PALE) technology. The effects of Al 0.3 Ga 0.7 As PALE interlayers with different growth sequences, AlAs/GaAs PALE and AlGa/AlGaAs PALE, on the morphological, structural and optical properties of GaAs epilayers were investigated. The results showed that Al 0.3 Ga 0.7 As PALE interlayers were preferred to eliminate anti-phase domains (APDs) and suppress Ge atoms outdiffusion at the heterointerface, effectively. Additionally, AlAs/GaAs PALE, the optimized growth sequence of Al 0.3 Ga 0.7 As PALE interlayers, could obtain the smoothest surface morphology (root-mean-square (RMS) 0.43 nm) and best crystalline quality, which was attributed to the control of AsH 3 exposure time ensuring fewer As vacancies acting as defect centers.

In this work, ZnO films with high crystal quality were grown by pulsed laser deposition (PLD) on different c-plane AlN/c-sapphire template thereby the thicknesses of AlN buffer layers varied from 150 to 300 nm. The properties of ZnO thin films were studied by using high-resolution X-ray diffraction, atomic force microscopy, photoluminescence spectroscopy, and Raman measurement. The comparative investigation results show that inserting an AlN buffer layer is an effective way to improve the crystal quality of ZnO films. Furthermore, the thickness of the AlN buffer layer plays an important role on the quality of ZnO films. The result of (0 0 0 2) ω-rocking curve with the full width at half maximum (FWHM) of 0.09° indicates that high-quality c-plane ZnO films can be achieved by using a 150 nm-thickness AlN/c-sapphire template. In the best knowledge of the authors, this is the minimum value reported at present for ZnO films grown on AlN/c-sapphire templates by PLD.

In this work, non-polar (1,1,−2,0) ZnO thin films have been grown on a -GaN/ r -Al 2 O 3 templates by radio-frequency magnetron sputtering. By varying the substrate temperature, the ZnO thin films were transformed from polycrystalline structure to epitaxial one on a -GaN/ r -Al 2 O 3 templates. High-quality (1,1,−2,0) ZnO epitaxial thin films were grown on the a -GaN/ r -Al 2 O 3 template at the optimized condition of 300 °C, which was confirmed by X-ray diffraction. The full width at half maximum (FWHM) of the (1,1,−2,0) ω -rocking curve of the a -plane ZnO films grown on the a -GaN/ r -Al 2 O 3 template was 0.51°, indicating a small mosaicity and a low dislocation density in the ZnO film grown on the a -GaN/ r -Al 2 O 3 template. Its surface roughness observed by atomic force microscopy was about 2.32 nm. Furthermore, the comparative investigation results show that the ZnO films grown on a -GaN/ r -Al 2 O 3 templates are more likely to form in the (1,1,−2,0)-orientation than those directly grown on r -sapphire.