铝锂合金被认为是在航空航天领域中实现飞行器轻量化的理想结构材料之一.采用高功率光纤激光器焊接1.76 mm厚的2198-T851铝锂合金,研究填充ER4047焊丝时激光功率、焊接速率和送丝速率对焊接热裂纹和焊缝组织的影响,以及最优焊接工艺下焊接接头的显微组织与力学性能.结果表明,当激光功率为4 kW,焊接速率为4 m/min,送丝速率为4 m/min时,填充ER4047焊丝焊接可获得成形良好且无宏观裂纹缺陷的焊接接头.接头的平均抗拉强度为342MPa,拉伸断裂后接头断裂强度达到母材的65.4％,熔合区为薄弱部位.

5083铝合金广泛应用于船舶、高速列车等制造领域。为了解决激光焊接对这类合金存在的凹陷和咬边问题,采用5087焊丝作为填充材料,对4mm厚的5083铝合金进行光纤激光焊接试验,分析了影响焊缝成形的主要因素,并对接头的组织、力学性能及断口特征进行了评价。研究结果表明:与自熔焊相比,填丝焊工艺参数为功率6kW,焊接速度7.5m/min,送丝速度4.5m/min,光丝间距1.0mm时能够消除焊缝表面的凹陷及咬边缺陷,获得成形饱满,组织细小的焊缝。填丝焊接头抗拉强度平均值为304MPa,约为母材的88%,比自熔焊提高了6.17%左右;延伸率平均为5.43%,比自熔焊提高了52%。拉伸后断于焊缝,断口呈现典型的韧性断裂特征。

This paper discusses a study in which Ti surface alloying has been performed on copper substrates by means of a double glow discharge plasma surface alloying technique. The micro-structure, the phase structure, the micro-hardness and the distribution of Ti concentration of alloying layer were investigated in detail by XRD, SEM and so on. The effect of process parameters on the alloying layer was studied. The experimental results show that a Ti solid solution with the precipitation Cu4Ti alloying layer has been formed on the copper surface. The thickness of the alloying layer is about 120 μm and the surface titanium concentration gradually decreases from w (Ti) = 87% to w (Ti) = 4%. The micro-hardness of the alloying layer is between 300 HV-800 HV. Source sputtering, surface absorption, ion bombarding and high temperature diffusion are the major factors that affect the alloying layer.

Physical method, including thermal evaporation and magnetic sputtering, and chemical coating method are applied to prepare organic-inorganic composite chromotropic film. The chromotropic film showing obvious opto-chromo effect with the change of incidence angle and view angle, can be used as a counterfeiting preventing material. The structure of the film system is designed as PET/Cr/dielectric/Al according to the optical interference principle of multiplayer. The dielectric materials are polymer and SiO2 respectively. The SiO2 prepared by sol-gel method shows nano-holes. Its refractive index is between 1.15 and 1.45 by varying the method and condition of catalyst and gel process. Fabrication method and film characteristics are described.

变色薄膜是一种非常有用的光学产品.用溶胶-凝胶SiO2作为变色薄膜中的介质层(Cr/SiO2/Al)能明显提高产品的质量和生产效率.本文介绍了溶胶-凝胶SiO2薄膜的制作方法,提出了用酸性催化控制SiO2溶胶过程;用网线辊涂布的方法形成薄膜,连同烘烤后处理完成SiO2凝胶过程.文章还对SiO2薄膜的光学特性和在制备变色薄膜中相关条件对整个薄膜性能的影响进行了分析.

The optically variable coatings can prevent counterfeiting of value documents. The cost of these coatings deposited by physical technology is very high. The sol-gel technology has the feature of a relatively lower cost and can be used to produce thin films with low refractive. We studied the optically variable coatings by the Nano-composite technology (i.e., compound method of sol-gel technology and physical technology). The degree of color shift of some film structures with the viewing angle, including PET(substrate)/Cr/SiO2/Al and PET(sub.)/Cr/resin/Al etc., was calculated according to the color perception of human eyes. And the coatings produced were measured with the spectrometer.

Sol-gel spin-coating technique was applied to produce tantalum pentoxide thin films. Pseudo-ternary phase diagrams were used to outline the sol-solution stability and the optimal Ta2O5 thin films formation regions of Ta(OC2H5)(5)-C2H5OH-CH3COOH-H2O system. Forbidden band gap of Ta2O5 thin film was calculated and found to be Eg=3.7 ev. Room temperature cyclic voltammetric measurements clearly revealed a protonic conductor behavior for Ta2O5 thin films.

The Mo/B4C multilayer system is selected for 6.7<λ<10.0nm X-rays. Mo/B4C multilayers are deposited by magnetron sputtering. The period thicknesses of these samples are from 3.35nm - 5.52nm. Details in the microstructure of Mo/B4C multilayer samples are revealed using X-ray diffraction and TEM. The results show that these multilayer mirrors have high structural quality and thermal stability.