Quantification of flank and crater wear in turning of AA7075/SiC composite

The machining of Al alloy/SiC composites is still a challenge, because the hardness of SiC particles is approximately 2700HV, which is much higher than the hardness of most tool materials. Therefore, the tool wears out quickly. This reduces the tool life and increases the surface roughness of the components of the Al alloy/SiC composites. Hence, there is an urgent need to investigate the influence of SiC particles on tool wear during the turning of 7075Al alloy composites and quantification of flank and crater wear in turning of AA7075/SiC Composite. The experimental tests for turning AA7075/15 wt.% (20-40µm) SiC composite, using coated tungsten carbide tools were conducted. Efforts were made to determine how the cutting speed, feed, depth of cut, and nose radius affect the flank and crater wear of carbide inserts, while turning AA7075/15 wt. % SiC. The effect of the AA7075/15 wt. % SiC composite elements, on tool wear were found out. SiC particles may be removed from the AA7075 matrix, or they may remain in matrix, during machining. If the SiC particles are removed, the tool will not be damaged. If SiC particles remained in the matrix, they scratched the tool flank. This results in excessive tool-flank wear. The results showed that flank and crater wear increased sharply with increasing of depth of cut. SiC was the main element responsible for the wear of the inserts. The novelty of this work is that, so far, little research has been conducted on the influence of elements present in AA7075 Al alloy/SiC composite on the wear of carbide inserts. In this work, investigations were conducted on the effects of elements in AA7075/15 wt. % SiC composite on wear of carbide inserts while machining of AA7075/SiC composites. Measures to minimize tool wear have also been reported. Wear of inserts due to presence of SiC particles in AA7075/15 wt. % SiC composite has been considerably reduced by using carbide inserts coated with titanium nitride (TiN).

铝合金基碳化硅（Al alloy/SiC）复合材料的切削加工仍是一项极具挑战性的课题，这是由于碳化硅（SiC）颗粒的硬度约为2700HV，远高于多数刀具材料的硬度，因此刀具磨损速度极快。该问题不仅会缩短刀具使用寿命，还会增大7075铝合金基碳化硅复合材料工件的表面粗糙度。因此，亟需开展针对7075铝合金（AA7075）基碳化硅复合材料车削过程中，碳化硅颗粒对刀具磨损影响的研究，并量化AA7075/SiC复合材料车削时的后刀面磨损（flank wear）与月牙洼磨损（crater wear）。本研究采用涂层硬质合金刀具（coated tungsten carbide tools）开展了AA7075/15重量百分比（20-40μm）SiC复合材料的车削试验，旨在探究切削速度、进给量、背吃刀量以及刀尖圆角半径对AA7075/15wt.%SiC复合材料车削时硬质合金刀片后刀面磨损与月牙洼磨损的影响规律，并明确AA7075/15wt.%SiC复合材料的组成成分对刀具磨损的作用机制。在车削过程中，碳化硅颗粒既可能从7075铝合金基体中脱落，也可能残留于基体内部。若颗粒脱落，则不会对刀具造成损伤；若颗粒残留于基体中，则会刮擦刀具后刀面，进而引发过量的后刀面磨损。试验结果表明：随着背吃刀量的增加，后刀面磨损与月牙洼磨损均会急剧加剧；碳化硅颗粒是导致硬质合金刀片磨损的主要因素。本研究的创新之处在于，目前针对AA7075铝合金基SiC复合材料组分对硬质合金刀具磨损影响的相关研究仍较为匮乏。本研究针对AA7075/15wt.%SiC复合材料组分对车削过程中硬质合金刀具磨损的影响开展了系统探究，并提出了降低刀具磨损的可行措施。通过采用氮化钛（TiN）涂层硬质合金刀片，可显著降低因AA7075/15wt.%SiC复合材料中碳化硅颗粒引发的刀具磨损。