深冷处理对TiAlN涂层刀具微观组织及力学性能的影响

Effect of Cryogenic Treatment on Microstructure and Mechanical Properties of TiAlN Coated Tool

深冷处理可改变涂层刀具的微观组织和力学性能,有助于改善刀具切削性能。在不同深冷温度(-110℃,-150℃,-190℃)下对TiAlN涂层硬质合金刀具进行深冷处理,并利用扫描电子显微镜(SEM)和X射线衍射观测不同深冷温度下硬质合金基体微观组织和物相结构变化,检测和分析了深冷处理前后涂层硬质合金刀具硬度和涂层-基体结合强度。结果表明,深冷处理能显著提高刀具硬质合金基体硬度和涂层-基体结合强度,且-190℃为最佳深冷处理温度。深冷处理促进硬质合金基体中η相碳化物的形成和粘结相Co的马氏体转变,使刀具性能得到提升。

In order to investigate the effect of cryogenic treatment on microstructure and mechanical properties of coated carbide tools,TiAlN coated carbide tools are cryogenically treated at different temperatures(-110℃,-150℃,-190℃).The changes of microstructure and phase structure of cemented carbide substrate at different cryogenic temperatures are observed by scanning electron microscopy(SEM)and X-ray diffraction and the hardness of TiAlN coated carbide tools,the bonding strength between the coating and the substrate materials are tested and analyzed.The results show that the hardness of cemented carbide substrate and the bonding strength between the coating and the substrate are significantly improved by cryogenic treatment and the optimal cryogenic temperature is-190℃for TiAlN coated carbide tools.The tool properties and performance improvements could be attributed to the formation and uniform distribution ofηphase carbide as well as the martensite transformation of the bonding phase Co in the tungsten carbide substrate under cryogenic environment.