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Sn precursor layer was evaporated on a glass substrate by an electron-beam evaporation method and followed by selenization using Se powder. SnSe film was successfully prepared by adjusting the selenization temperature and selenization time. The phase, microstructure and optical properties of the SnSe films were studied by X-ray diffraction, Raman spectroscopy, Scanning Electron Microscopy, and UV-Vis-NIR spectrophotometer. The results demonstrated that the pure phase polycrystalline SnSe films with a band gap of 0.93 eV could be prepared by selenizing at 450 ∘ C for 60 min. Under the irradiation of a 980 nm laser with a power of 2 mW/cm2, photoelectric response characteristics of the SnSe films were tested, and the response time and recovery time of the prepared film were 62 ms and 80 ms, respectively, indicating that the SnSe film had a large application prospect in near-infrared light detection. [ABSTRACT FROM AUTHOR]

Aluminum alloy 6061(AA6061) sheets of 4 mm in thickness are joined by laser wire-filling welding (LWFW) using the ER4047 welding wire. Microstructure and alloy element distributions near the fusion line are characterized and are investigated by optical microscope, scanning electron microscope, energy dispersive spectrometer. The results showed that the well-formed welded joints are obtained with a few thermal cracks near the fusion line. The coarse grain and a reduction in the weight ratio of magnesium to silicon can be observed, when the welding speed decreases under constant laser power. The thermal crack is caused by the decrease of the weight fraction of magnesium and the proportion of silicon content has an effect on the microhardness of welded joints. By properly controlling the welding speed, the various properties of AA6061 LWFW joints can be balanced. [ABSTRACT FROM AUTHOR]

The welding sequence has an important influence on the formation of stress and deformation in multi-layer and multi-pass welding (MLMPW). In this paper, a 3D finite element model of Invar alloy welding that can calculate the welding stress and deformation has been established using MSC. Marc. The simulation results show that there is high residual tensile stress in the welding zone. For six-layer twelve-pass welding, the welding sequence has little effect on maximum stress value. Meantime, welding deformation is mainly distributed far from the weld metal area and is mainly affected by welding sequence under similar other welding conditions. It is found that the deformation angle of welding sequence D is the smallest, with a value of 0. 6 4 6 ∘ . [ABSTRACT FROM AUTHOR]