SiCp/Al复合材料薄壁件切削加工变形、损伤机理及抑制方法研究

SiCp/Al composites thin-walled parts have wide application development prospects in the high-technology fields, and the cutting deformation and vibration are very different from that of the thin-walled made of metal material. In addition, the damage and even destroy produced in cutting process are also unique, important and lack of study both for home and abroad. In this project, according to the structural characteristics of SiCp/Al composites, the cutting deformation and vibration theoretical model of SiCp/Al composites thin walled part, and the cutting damage initiation and evolution mechanisms will be proposed based on the micro mechanics theory. At the same time, the simulation and experimental methods will be used to investigate the cutting deformation, vaibration and damage characteristics, mechnisms and the influencing factors during high-speed milling, high-speed turn-milling and precision turning of SiCp/Al composites non-rotary and rotary thin-walled part, therefore, the thermo-dynamic conditions and cutting process parameters used to reduce the cutting deformation and damage can be proposed. Then, the theoretical models,mechanisms and methods of the fluid servo dynamic support system will be established to suppress deformation and vibration effectively, which can realize the precision machining of SiCp/Al composites thin-walled part. Therefore, this work has an important theoretical and practical significance for perfecting and development the machining theory, and it will also promote the application of SiCp/Al composites thin-walled and related scientific and technological development.

SiCp/Al复合材料薄壁件在高新技术领域具有广阔的应用发展前景，其切削变形和振动特性有别于金属材料薄壁件，切削过程产生的损伤甚至破坏，也是其独特而重要的问题，目前国内外尚缺乏相应研究。本项申请拟根据SiCp/Al复合材料的材料结构特点，提出以细观力学为基础的SiCp/Al复合材料薄壁件切削变形、振动的理论模型及切削损伤萌生和演化机制，应用数值模拟和实验方法，对SiCp/Al复合材料非回转体和回转体薄壁件在高速铣削、高速车铣、精密车削加工条件下的切削变形、振动及损伤特性、机理和影响因素进行深入系统的研究，提出减小切削变形和损伤的热力学条件及切削工艺参数，建立流体随动支承抑制变形及振动的理论模型和机制、方法，实现SiCp/Al复合材料薄壁件的精密切削加工。本项研究对促进切削加工理论的完善和发展，推动SiCp/Al复合材料薄壁件的应用及相关科学技术的发展，具有重要的理论和实际意义。

SiCp/Al复合材料薄壁件的加工变形、损伤是影响其在高技术领域应用发展的重要问题，具有特殊性。本项目应用有限元仿真和实验方法对切削力、切削温度、表面形成、加工变形、损伤、动态特性、抑制方法等进行了系统研究。具体如下：.　　1）提出了板状和圆筒状SiCp/Al复合材料薄壁件在高速铣削、高速车铣及车削时，切削用量、刀具角度、铣削方式、加工路径、切削位置对切削力、切削温度和已加工表面粗糙度的影响规律，建立了切削力、切削温度经验公式。对促进SiCp/Al复合材料薄壁件精密切削理论的发展，实现其精密切削具有重要意义。. 2）提出了SiCp/Al复合材料切削加工表面形成机理和铣削方式对已加工表面宏、微观形貌特征及形成机制的影响，指出高速车铣铣削方式对表面形貌和粗糙度的影响不同于高速立铣；提出了SiCp/Al复合材料的切屑形态和已加工表面缺陷特征；提出了不同粒度PCD刀具材料的磨损机理和耐磨特性。对表面形貌控制、刀具材料选择及磨损机理研究具有重要意义。. 3）提出了板状和圆筒状SiCp/Al复合材料薄壁件的变形特征；获得了铣削方式、切削用量、刀具角度、加工路径、薄壁件几何尺寸对工件变形、应力分布及加工让刀的影响规律。为减小加工变形，提高加工精度提供理论依据。. 4）提出了SiCp/Al复合材料裂纹形成及扩展的机理和特征，获得了SiCp/Al复合材料薄壁件的断裂损伤形成特征；提出了高速铣削板状薄壁件的边界损伤和边缘过切形成机理。对减小切削损伤，提高加工质量具有重要意义。. 5）提出了SiCp/Al复合材料薄壁件的模态、固有频率、阻尼等动力学特性及影响因素；提出了板状和圆筒状薄壁件在动载荷作用下的瞬态变形特征。建立了流体随动辅助支承方法，提出了流体随动辅助支承对加工变形、让刀及表面粗糙度的影响。为抑制SiCp/Al薄壁件的加工变形、损伤，提高加工精度和表面质量提供了一种新的方法。