【作者】 苏阔；

【导师】 康仁科；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2012， 硕士

【摘要】 铝基碳化硅复合材料是以铝合金作为金属基体,加入一定量的碳化硅颗粒,经过一系列处理工艺,制备的特殊材料。铝基碳化硅复合材料除了具有基体金属或合金所具备的良好的抗冲击性能、抗疲劳性能、导热性能、导电性能和抗断裂性能以外,还具有较高耐磨性能和较低热膨胀系数,同时强度、刚度都很高。铝基碳化硅复合材料现在被广泛应用于在机械、汽车、航空航天、电子、光学等领域,成为应用较为广泛的新型材料。铝基碳化硅复合材料由于其特殊的组成及物理性能,传统切削加工中存在很多问题。传统加工过程中,铝合金基体局部熔化,生成积屑瘤,刀具磨损变钝,造成粗糙度下降,难以获得高质量的加工表面,相应的形位、尺寸公差也就很难保证。刀具磨损剧烈,导致加工成本高,同时,加工时硬质碳化硅颗粒会破碎、脱落,然后与切削液混合在一起,对机床造成极其不利的影响,降低机床寿命。随着碳化硅体积分数和碳化硅颗粒尺寸的不断变大,铝基碳化硅复合材料的加工会变得越来越难,这严重阻碍了其进一步的广泛应用。由于铝基碳化硅复合材料加工出现以上加工问题,本论文拟采用超声辅助磨削的工艺对其加工情况进行改善,重新设计并制造了超声辅助磨削系统,并对其加工铝基碳化硅复合材料的工艺进行研究。主要的工作和研究内容如下：1)超声辅助磨削试验平台的重新设计和搭建。根据实际条件以及加工试验的需要,重新设计了超声振动刀柄的结构零件,尤其对超声刀柄结构和工具磨头等进行了深度改进。试验平台是基于一台自制数控立式铣床的改造,在数控立式铣床上安装超声振动刀柄和Kastler三向测力仪等设备,完成超声辅助磨削试验台的搭建。2)进行铝基碳化硅复合材料超声辅助磨削工艺研究,主要从超声辅助磨削切削力和刀具磨损两方面进行试验对比,通过试验研究主轴转速、进给速度和磨削深度等参数对磨削力的影响,通过与同参数下普通磨削的磨削力的对比,超声辅助磨削的磨削力降低幅度在20%-50%之间。3)进行铝基碳化硅复合材料超声辅助磨削表面粗糙度和表面形貌研究,设计不同的加工工艺参数进行单因素对比试验和超声辅助磨削铝基碳化硅的正交试验,通过试验研究各加工参数对表面粗糙度的影响规律。4)根据铝基碳化硅复合材料的特殊性质,对其亚表面损伤检测工艺进行了研究。通过铝基碳化硅复合材料亚表面形貌研究,发现铝基碳化硅超声辅助磨削表面粗糙度较差的原因,并对其超声辅助磨削的材料去除机理进行了研究。更多还原

【Abstract】 SiCp/Al composite is a stiff particle-reinforced metal matrix composite, of which aluminum alloy is used as the metal matrix and SiC particles are the reinforced phase. With the advantages such as high conductivity, high thermal conductivity, specific strength and specific rigidity, small linear expansibility, good dimension stability and heat resistance, good fatigue performance and low price, etc., SiCp/Al has been widely used in industries such as aviation, automobiles, electronic packaging, astronomy and optics.Due to high strength hard and brittle SiC ceramic grain being added, this material has been improved in mechanical properties and is seen to possess isotropic properties under macrography. However, owning to the SiC particle reinforcement, many difficulties are found in machining the material such as heavy tool abrasion, larger cutting force, BUE and high cutting temperature, which make the tool life shorten. In addition, material removal mechanism of SiCp/Al composite is different from ordinary metal materials and it is difficult to ensure good surface quality and machining precision by traditional surface processing. With the increasing of the SiC volume fraction in SiCp/Al composites, machining is one of the major problems that resists its wide spread engineering application.To solve the machining problems of SiCp/Al composite, an ultrasonic assisted grinding system was developed in this paper. Some researches were carried out about processing performance of the ultrasonic assisted grinding of materials. The main work and results are as follows:1. The ultrasonic assisted grinding test platform was set up. According to the test requirements and the conditions of processing, the ultrasonic generator and the ultrasonic structure devices were designed. Based on self-designed vertical drilling and milling machine, ultrasonic devices and three-dimensional dynamometer were installed to complete the preparation for the experiments.2. This paper researches on the contrast experiments between ultrasonic assisted grinding and traditional grinding about the grinding force. The influence of grinding parameters such as grinding force, spindle speed, feed rate and grinding depth on the grinding force were obtained. Compared with the traditional method, the grinding force could be reduced by50%at most in the ultrasonic machining.3. This paper also presented a study of the surface qualification of ultrasonic assisted grinding and common grinding. By observing surface morphology and testing the surface roughness, it could be seen that the surface qualification of SiCp/Al by ultrasonic grinding was worse than that by common grinding.4. According to the characteristics of SiCp/Al composite, the paper contains a research on the SiCp/Al composite subsurface damages testing method. Through the research on the subsurface damages of SiCp/Al machined by ultrasonic grinding, the reason that the SiCp/Al surface roughness by ultrasonic is worse than that by common grinding was found. After all the researches, the paper presented the processing mechanism of ultrasonic assisted grinding SiCp/Al composite.更多还原