Al/SiC_p复合材料铣削加工损伤形貌与分析

Surface Observation and Analysis of the Milling Damage of Al/SiC_p Composites

利用硬质合金涂层刀具开展了SiC颗粒(体积含量15%、平均粒径14μm)增强铝基复合材料(简称Al/SiCp复合材料)的铣削加工试验,并采用扫描电镜(SEM)对加工表面损伤与刀具刃口形貌进行显微观察与分析,利用表面轮廓仪对加工表面粗糙度进行测量.经分析发现,当切削深度与进给量较小时,加工表面完整性较好,随着切削深度与进给量的增加,加工表面出现了周期性的裂纹损伤,并从金属切削原理与复合材料位错理论对加工损伤机理进行了探讨.

The Al/SiCp composites, having 15% volume ratio of SiC particles with average grain size 15μm, were milled by using a Coated tungsten carbide endmill in this study. A scanning electron microscopy （SEM） is utilized for observing the machined workpiece surfaces, the cutting tool edges, and a surface profilometer for inspecting surface roughness. Based on the surface observation and surface roughness inspection, it is found that, when feedrate and depth of cut are smaller than limited values, satisfactory surface finish can be attainable, however, as the depth of cut and feedrate increases, the microcraeks are first initiated at the interface of SiC particles and aluminum matrix, and then periodically macrocracks are formed on the machined surface. The damage mechanisms during the machining of aluminum/SiCp are discussed in this paper based on metal cutting theory and dislocation movement theory of composites.