SiC_p/Al复合材料超精密车削切屑形成机制及形成过程模型  

Chip Formation Mechanisms and the Process Model during Ultra-precision Turning of SiC_p/ Al Composite

作　　者：葛英飞[1] 徐九华[2] 杨辉[3] 

机构地区：[1]南京工程学院机械工程学院,江苏南京211167 [2]南京航空航天大学机电学院,江苏南京210016 [3]北京航空精密机械研究所,北京100076

出　　处：《兵工学报》2015年第5期911-920,共10页Acta Armamentarii

基　　金：国家自然科学基金项目(51275227);江苏省青蓝工程项目(2014年)

摘　　要：通过观察切屑根部和切屑的形态及金相微观组织,采用细观分析法和金属切削理论分析法相结合,研究、分析了天然单晶金刚石(SCD)和聚晶金刚石(PCD)刀具超精密车削Si Cp/2024Al和Si Cp/ZL101A复合材料时的切屑形成机制,并建立了这两种材料的切屑形成过程模型。结果表明:切屑呈厚度准周期性变化的锯齿状;切削变形时工件材料中微裂纹的动态形成和扩展、剪切角周期变化是形成这种切屑形态的两种主要机制;该材料微观上的不均匀性、材料本身的各种缺陷以及大量不可变形增强颗粒的存在,使得切削时剪切区材料产生大量的微裂纹和微空洞,而其微观组织特性、力学性能特性以及切削时周期性的滑-停现象决定了剪切角周期变化;增强颗粒体分比、切削速度、进给量、刀具刃口半径是影响切屑形成的主要因素。Single crystal diamond and polycrystalline diamond tools are selected for ultra-precision turning of SiC particulate reinforced aluminum matrix composites （SiCp/2024Al and SiCp/ZL101A）.The appearance and the metallurgical microstructure of chip are observed in order to investigate the formation mechanisms of chip using micromechanics and metal cutting theory analytical methods.The chip formation process models are also established.The results show that a saw-toothed chip with semi-periodic thickness is formed.It is pointed that the dynamic behavior of microcracks and the periodic variation of shear angle are the two main mechanisms for this type of chip.A great number of microcracks and microvoids are produced on this kind of material during machining due to the inherent defects and,non-uniformity of the materials and the presence of the reinforcement particles.The periodic variation of shear angle is determined by the workpiece microstructure and the mechanical properties and the periodic slipstick phenomenon.Volume fraction of reinforcement,cutting speed,feed rate and tool edge radius are the main factors that affect the chip formation.

关 键 词：机械制造工艺与设备 颗粒增强铝基复合材料 超精密车削 切屑形成机制 形成过程模型 微裂纹动态形成和扩展 剪切角 

分 类 号：TG506.7[金属学及工艺—金属切削加工及机床]