| Summary: | 碩士 === 國立雲林科技大學 === 機械工程系 === 105 === In many surface treatment process, the laser has the advantage of small thermal deformation, can get very fine hardened layer structure and non-pollution for the environment, but the disadvantage is based on different absorption rate of materials, need to use different wavelengths of laser to achieve higher the energy conversion. Ion beam or electron beam is no such worries, and can achieve the same surface treatment effect like the laser, but the processing environment to be vacuum, in order to avoid ions or electrons collide with other gas molecules, resulting in energy loss and dissociation of other elements, to avoid the material there are unnecessary compounds on the surface.
In this study, combined with the plasma assisted laser dual heat source innovation mechanism, in the self-designed internal and external hollow electrode nozzle structure induced discharge plasma flow, and the laser through the inner and outer nozzle center, the double heat source coaxial to the processing parts, the use of additional heat of the discharge plasma to improve the material temperature, increase the material on the laser absorption rate, and high activity of the gas plasma, so that the combination of surface and gas effect is more improved. In this method, first step establishes the system design and device test of double heat source, and test the effect of different parameters on the surface shape and microstructure of Ti-4Al-6V alloy.
In the study early-stage for improved YAN-RU JHENG design of institutions, and test plasma flow the temperature and image measurement. In flow field simulation was informed in the new external electrodes can increase flow rate. The result of beam measurement results of plasma test, temperature increase 10% and 28% correspond air and nitrogen plasma, the image measurement of length increase 8%.
The results show that the method can increase the temperature of the material to improve the way of the laser absorption rate of the Ti-4Al-6V titanium alloy by using the discharge plasma. The surface roughness(Sa) reduced by about 18%, the nitrogen plasma assisted laser surface component analysis, still can detect a high proportion of oxygen, because the processing environment is open, during the process the discharge plasma bundles mixed with air resulting in. The surface of the material is mainly oxide (TiO、 O3V7). In hardness, because the material after the natural cooling, so that the material annealing, so the hardness of the surface of the material than the internal low.
Keywords: laser, plasma assisted, surface treatment
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