Mg alloys are superior to other metallic biomaterials for temporary bio-application, owing to their biodegradability and biocompatibility features. However, the high reactivity and the rapid corrosion rate of Mg alloys are major barriers for their usage in bio-applications. In this paper, laser surface modification method is used to improve the surface properties of WE54. A 500 W pulse Nd: YAG laser beam is focused on the specimen through a 2 mm layer of simulated body fluid. As a result, a new microstructure and a Ca/P layer are obtained in a single process, which is conductive for the cell attachment.
Optical waveguides with a propagation loss of around 0.5 dB/cm are written inside photosensitive Foturan glass by
internal modification of refractive index using femtosecond (fs) laser. Integration of the optical wafveguides with a
micromirror enables us to bend the guided laser beam at an angle of 90° with a bending loss of less than 0.3 dB. In the
meanwhile, a plano-convex microlens is completely embedded inside the Foturan glass chip via formation of a three-dimensional
(3D) hollow microstructure using fs laser direct writing followed by heat treatment and successive wet
etching. This technique can also be used to fabricate microfluidic devices and therefore realizes 3D integration of
microoptical and microfluidic components by one continuous procedure. Subsequently, microoptical waveguides are
further integrated into the single glass chip. Demonstration of optical measurements using the integrated microchip
reveals that photonic biosensing can be performed with an efficiency increased by a factor of 8 for fluorescence detection
and by a factor of 3 for absorption detection.
Infrared thermograph technology in the research of laser-matter interaction was discussed. The formation of molten pool and heat transfer and matter transfer in laser repairing cracks of components were investigated using infrared thermal imaging system. Because the software system of HWRX-3 thermovision is not compatible with the present computer and operation system, we discussed several methods, where the compatibility has been solved and the image processing system can be transformed to windows operation system by the redesign software. The friendly user interface and very high visibility of the optimized software have been testified during laser repairing cracks of components processing. One practical method of digital process for the investigation on heat transfer and matter transfer in laser repairing cracks of components has been developed.
High critical current density and in-plane aligned YBa2Cu3O7-x (YBCO) films on textured yttria- stabilized zirconia (YSZ) buffer layers deposited on NiCr alloy (Hastelloy c-275) substrates by laser ablation with only O+ ion beam assistance were fabricated. The X- ray Phi-scan full width at half-maximums for YSZ (202) and YBCO (103) were 18 degree(s) and 11 degree(s) respectively. A critical current density of 7.9 X 105 A/cm2 of YBCO films was obtained at liquid nitrogen temperature and zero field. The critical temperature of the YBCO tape was 90 K.
The CeO2 films were deposited by pulsed laser ablation on stainless steel substrates at room temperature with the Ar+ ion beam assistance. The results show that when the CeO2 films were deposited directly on the stainless steel substrates, the desired (001)-normal textured were achieved, but there was no evidence for alignment of in- plane crystal axes. Further experimental results indicate that CeO2/YSZ (Yttria-Stabilized Zirconia)/stainless steel films deposited under the same conditions are not only normal orientation to the substrate's surface but also highly in-plane textured.
Investigation into the behavior characteristics of particle phases in laser cladding WC-TiC-TaC/Co based ceramic-metal composite coating suggested that TiC particles had exhibited a continuous increase in amount from the bottom to the top of clad layer, and partial TiC particles gathered and became large. Partial WC and TaC particles exhibited smashing phenomenon (heat damage), and the degree of heat damage of both WC and TaC particles was much more serious than that of TiC particles. Experimental results also showed that there existed obviously a surrounding structure (Ti, W, Ta) C at edge of carbonitride phase TiC in clad coating. In addition, ledeburite with shape of fish-bone was generated in the toppest region of clad coating, coarser eutectic microstructures was generated in boding zone of clad coating in the liquid state solidifying process, and both of these microstructures contained W, Ti, Ta etc. elements.
Investigation has been carried out into the solidification features and formation law of microstructure for laser cladding Co-base Cr-W Alloy Laser on Stainless Steel Valve. It is shown that the microstructure at the cladding layer bottom belongs to typical epitaxial growth on basis of plane, and the dendrite crystal is coarser. The microstructure at the top is the regular pine-tree eutectic crystal, and at the middle is small cell crystal and columnar crystal. The crystalline anisotropy influences the crystal growth form. Grain nucleation has obvious features of heterogeneous nucleation in microstructure of cladding. The results also show that the compositions in microzone of cladding layer are non-uniform, different elements segregate along crystalline axis or interdendritic, and these have resulted in the non-uniform microstructure.
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