采用聚晶立方氮化硼 (PCBN) 、TiAlN涂层硬质合金 (2种刀尖圆弧半径) 和Al2O3+TiC涂层硬质合金等3种刀具车削TC4钛合金工件, 测试了刀具后刀面磨损宽度和工件表面粗糙度, 观察了刀具的磨损形貌并分析了磨损机制;同时, 研究了刀尖圆弧半径对工件表面粗糙度和切屑形貌的影响.结果表明:TiAlN涂层硬质合金刀具具有比其他2种刀具更长的使用寿命, 且加工后工件的表面粗糙度最小、表面质量最好, 其磨损形式主要为磨粒磨损和黏结磨损;PCBN刀具的失效形式主要为前刀面和后刀面崩塌, 而Al2O3+TiC涂层硬质合金刀具的磨损形式主要为扩散磨损;刀尖圆弧半径的增大有利于提高TiAlN涂层硬质合金刀具的断屑能力以及加工工件的表面质量.%Three tools made of polycrystalline cubic boron nitride (PCBN), TiAlN coated cemented carbide (two tool tip corner radii) and Al2O3+TiC coated cemented carbide, respectively, were used to turn TC4 titanium alloy workpiece.Wear width on flank face of the tools and surface roughness of the workpiece were measured, wear morphology of the tools was observed and wear mechanism was analyzed.Meanwhile, effects of tip corner radius on surface roughness of the workpiece and chip morphology were studied.The results show that the TiAlN coated cemented carbide tool had a longer service life than the other two tools.After machining with the TiAlN coated cemented carbide tool, the workpiece had the smallest surface roughness and the best surface quality;the wear form of the tool was mainly abrasive wear and adhesive wear.The failure mode of the PCBN tool was mainly collapse of the rake face and flank face, while the wear form of the Al2O3+TiC coated cemented carbide tool was mainly diffusion wear.Increasing tip corner radius was beneficial to improving chip breaking ability of the TiAlN coated cemented carbide tool and surface quality of the workpiece.
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