Surface integrity of high speed milling of Al/SiC/65p aluminum matrix composites

The surface quality of components produced through milling of particle reinforced aluminum matrix composites (PRAMCs) is one of the most important factors influencing their practical performance. Therefore, the increasing applications of PRAMCs necessitate an in-depth understanding of the variation law of surface integrity. This paper presents a systematic experimental research of high speed milling of Al/SiC/65p (65% volume fraction) by polycrystalline diamond tools (PCD). The influences of cutting parameters on surface roughness (Ra), surface residual stress (RS) and morphology of PRAMCs were investigated. In addition, the experiments on corresponding unreinforced matrix alloy Al 6063 were also carried out to analyze the influence of the present reinforcements on surface integrity. The results of full factorial experiment revealed that the most significant milling parameter for surface roughness was milling speed, followed by the interaction between feed rate and milling speed, then the feed rate. In terms of residual stress on the machined surface, axial depth of cut had the highest influences on surface residual stress, followed by milling speed and feed rate. The results of single-factor experiment demonstrated that surface roughness improved slightly with the decrease in the feed rate, while the effect of milling speed was negligible. Residual stress measured in feed direction by X-ray diffraction (XRD) indicated that the conditions of machined Al6063 surface were all tensile, while the conditions of Al/SiC/65p were compressive.