激光表面微织构加工及减阻技术研究

发布时间：2018-02-09 17:19

本文关键词： 激光表面微织构加工工艺润滑减阻　出处：《宁波大学》2017年硕士论文　论文类型：学位论文

【摘要】：表面微织构技术在摩擦减阻领域可以发挥巨大的作用。本文探讨了激光表面微织构加工技术对氧化铝陶瓷和氮化硅陶瓷的加工能力,并利用实验和仿真分析了流体润滑情况下凹坑型表面微织构对材料摩擦学性能的影响。通过采用大功率纳秒激光器,本文对单点多脉冲加工工艺和环形填充加工工艺在氧化铝陶瓷凹坑型表面微织构的制备能力进行了分析。实验发现,单点多脉冲加工工艺加工效率高、产生的残余应力小,但加工质量对光斑质量依赖性较强,制备的微织构凹坑直径的变化范围在18-53μm之间;环形填充加工法应用范围更广,可以用来制备凹坑直径大于70μm的凹坑型表面微织构。环形填充方式工艺参数的调整可以有效地提高加工质量,但加工效率相对较低。实验还对超短脉冲皮秒激光对氧化铝陶瓷和氮化硅陶瓷凹槽型表面微织构的制备能力进行了分析。结果表明:调整平均功率、扫描速度、重复次数等工艺参数可有效地降低凹槽底部粗糙度、减小凹槽壁面锥度和减少氧化产物。本文利用摩擦磨损试验机分析了凹坑型微织构对耐磨性工程材料聚酰亚胺摩擦性能的影响。结果表明:凹坑型表面微织构可以有效地提高聚酰亚胺材料流体润滑时的摩擦学性能。一定间距的表面微织构可以有效地提高摩擦副的承载能力,减小摩擦副间的摩擦力,但间距过小时,加工过程产生的毛刺会严重影响表面粗糙度,从而使摩擦力增大。当凹坑边缘间距大于10μm,凹坑直径30μm、深度10-15um时摩擦学性能最好。通过对弧型凹坑表面微织构流体润滑状态的摩擦学性能进行数值模拟,得出结论:表面微织构的引入能够增加法向承载,并且减小水平方向的摩擦力;表面微织构的动压润滑性能与织构参数的变化规律及流体域中涡流有关,流体域中涡流不利于法向承载的增大和摩擦力的减小。在实验条件下当凹坑深度为5-10μm,凹坑宽度40μm时摩擦学性能达到最优。本文的实验结论在陶瓷等硬脆性材料的织构化处理和微织构减阻技术在聚酰亚胺等耐磨性材料的应用方面具有一定的指导意义。
[Abstract]:Surface microtexture technology can play an important role in friction and drag reduction. In this paper, the processing ability of laser surface microtexture on alumina and silicon nitride ceramics is discussed. The effect of surface microtexture on the tribological properties of the material under fluid lubrication is analyzed by using high power nanosecond laser. In this paper, the preparation ability of single-point and multi-pulse processing technology and annular filling process on the micro-texture of alumina ceramic pit surface is analyzed. It is found that the single-point multi-pulse processing process has high processing efficiency and small residual stress. However, the processing quality has a strong dependence on the spot quality, and the diameter of the prepared microtexture pits varies from 18 to 53 渭 m, and the annular filling method is more widely used. It can be used to fabricate concave surface microtexture with pit diameter greater than 70 渭 m. The processing quality can be improved by adjusting the technological parameters of annular filling method. But the processing efficiency is relatively low. The preparation ability of ultrashort pulse picosecond laser on the grooved surface microtexture of alumina and silicon nitride ceramics is analyzed. The results show that the average power and scanning speed are adjusted. The process parameters such as repetition times can effectively reduce the bottom roughness of the grooves. In this paper, the effect of pit microtexture on the friction properties of polyimide was analyzed by friction and wear tester. The results show that the surface microtexture of pit type can be used to reduce the surface taper of grooves and reduce the oxidation products. In order to effectively improve the tribological properties of polyimide materials under fluid lubrication, the bearing capacity of friction pairs can be effectively improved by surface microtexture with certain spacing. Reducing the friction force between the friction pairs, but if the distance is too small, the burrs produced during the machining process will seriously affect the surface roughness. Thus the friction force is increased. The tribological performance is the best when the edge spacing of the pit is greater than 10 渭 m, the pit diameter is 30 渭 m, and the depth is 10-15 um. The tribological properties of the micro-texture fluid lubrication state on the surface of the arc pit are simulated numerically. It is concluded that the introduction of surface microtexture can increase the normal bearing capacity and decrease the horizontal friction force, and the hydrodynamic lubrication performance of the surface microtexture is related to the variation of texture parameters and the eddy current in the fluid domain. The eddy current in the fluid domain is not conducive to the increase of normal load and the decrease of friction force. Under experimental conditions, the tribological properties are optimized when the depth of the pit is 5-10 渭 m and the width of the pit is 40 渭 m. Texture treatment and microtexture drag reduction technology have a certain guiding significance in the application of polyimide and other wear-resistant materials.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ174.6;TN249

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