基于热循环后复合水介质仿生表面强化灰铁的磨损性能分析

发布时间：2018-04-29 20:37

本文选题：水介质激光仿生 + 灰铁　；参考：《长春工业大学》2015年硕士论文

【摘要】：利用激光的灵活性及可局部加工的特点,根据仿生学原理,所制备的对生产环境和使用环境的要求较低的材料和形状为耦元的仿生材料是大多数生产者和使用者欢迎的一种提高材料性能的一种较新的途径。然而随着列车的提速,对制动盘材料有了更高的要求,另外,制动盘在列车制动系统中起到了不可替代的关键作用,再加上它所安装的位置的较难更换,都时刻催促着研究者对制动盘的进一步研究,能够通过研究其工作原理,较准确的取其精华,去其糟粕。众所周知,制动盘主要是靠表面摩擦制动的,因此大部分摩擦磨损行为都发生于表面。从仿生原理的角度分析,通过提高冷却速率的水介质激光仿生处理工艺来提高其仿生单元体的硬度可以大幅度提高材料的抗磨损性能,这在以往的实验室基础的单独的磨损实验中得以验证。然而在实际工况下,材料除遭受一定程度的磨损外,长时间的制动摩擦过程会使得制动盘表面温度急剧升高,而频繁的制动会导致其表面在冷热交替的作用下发生磨损,在这种磨损和由冷热交替环境而产生的热循环应力的双重作用下很容易导致零件的失效。为了了解热循环后水介质仿生试样的抗磨损性能,本实验将仿生单元体表面含有裂纹的仿生灰铁进行了ANSYS应力-应变分析,发现虽然仿生灰铁可大幅度降低普通灰铁四周的应力集中现象,减少材料磨损过程中发生的应变,但含有裂纹的仿生单元体却在一定程度上降低了仿生试样对普通灰铁的抗磨损性能的提高幅度。为了得到更好性能的仿生灰铁,本实验针对于具有较好的抗磨损性能的,却有大量表面裂纹缺陷的激光水介质仿生灰铁试样,进行了复合水介质仿生表面强化处理。另外,本文创新的将经过热循环实验与磨损实验共同作用后的水介质仿生试样与未经热循环实验的传统磨损实验进行对比,分析水介质仿生单元体材料表面质量与经热循环后水介质仿生试样整体表面变化情况的联系及其热循环后的磨损性能影响,为水介质激光仿生表面加工的灰铁的工程应用提供理论依据及实验基础。与此同时,通过改善水介质单元体表面质量的复合水介质激光仿生表面强化的方法,有效提高了其热循环后的磨损性能。得到了更适合实际应用环境的仿生灰铁材料。
[Abstract]:According to the principle of bionics, using the flexibility of laser and the characteristic of local machining, It is a new way for most producers and users to improve the properties of materials with low requirements for production environment and use environment and bionic materials with the shape of coupling element. However, with the increase of the speed of the train, the material of the brake disc has higher requirements. In addition, the brake disc plays an irreplaceable role in the braking system of the train, and the position it installs is more difficult to replace. All the time urge researchers to further study the brake disc, through the study of its working principle, more accurately select its essence and discard the dross. As we all know, the brake disc is mainly braking by surface friction, so most of the friction and wear behavior occurs on the surface. From the point of view of bionic principle, the hardness of the bionic unit body can be improved greatly by increasing the cooling rate of water medium laser bionic treatment process, and the wear resistance of the material can be greatly improved. This has been verified in previous laboratory-based wear tests. However, under the actual working conditions, the surface temperature of the brake disc will rise sharply after a long period of braking friction, and the frequent braking will cause the surface to wear under the action of alternate heat and cold, except that the material is subjected to a certain degree of wear, and the friction process of braking for a long time will cause the surface temperature of the brake disc to rise sharply. It is easy to lead to the failure of the parts under the double action of the wear and the thermal cycling stress caused by the alternate environment of cold and heat. In order to understand the wear resistance of bionic samples in water medium after thermal cycling, the ANSYS stress-strain analysis of bionic gray iron with cracks on the surface of bionic elements was carried out in this experiment. It is found that although bionic gray iron can greatly reduce the stress concentration around the ordinary gray iron and reduce the strain occurring during the wear of the material, However, the bionic element with cracks decreases the wear resistance of the bionic sample to some extent. In order to obtain bionic lime-iron with better performance, the biomimetic lime-iron samples with good wear resistance but a large number of surface crack defects were treated by bionic surface strengthening of composite water medium. In addition, this paper innovatively compares the water medium bionic specimen with the traditional wear experiment without thermal cycling experiment after thermal cycling experiment and wear experiment. The relationship between the surface quality of water medium biomimetic unit material and the change of the whole surface of the water medium bionic sample after thermal cycling and the effect of thermal cycling on the wear performance are analyzed. It provides a theoretical and experimental basis for the engineering application of lime-iron produced by laser bionic surface processing in water medium. At the same time, by improving the surface quality of the water medium unit, the laser bionic surface strengthening method of the composite water medium can effectively improve the wear performance of the composite water medium after thermal cycling. The bionic lime-iron material which is more suitable for practical application is obtained.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB391

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