TiSiN/TiAlN涂层刀具高速车削TC4钛合金磨损机理分析

Analysis of Wear Mechanism of TiSiN/TiAlN Coated Cutting Tools in High-speed Turning TC4 Titanium Alloy

本文研究双层TiSiN/TiAlN涂层刀具车削TC4钛合金时的磨损机理,用扫描电镜观察刀具的磨损形貌。涂层刀具前刀面的磨损区域分为死区、黏结区和滑动区。各区的磨损机理不同,死区几乎没有磨损;黏结区的涂层受高温度和高压力的影响而失效;滑动区的涂层由切屑在前刀面滑动摩擦造成失效。通过测力仪获得切削力,在低进给量工况下,受已加工表面的回弹影响,背吃刀力和进给力比主切削力更大。通过红外热像仪获得切屑自由表面的温度,结果显示,随着进给量增大切屑厚度也增大,切屑自由表面温度没有升高。

The wear mechanism of the double-layer TiSiN/TiAlN coated tool in turning TC4 titanium alloy is studied.The wear morphology of the tool is observed by scanning electron microscope.The wear zone of the rake face of the coated tool is divided into dead zone,sticking zone and sliding zone.The wear mechanism of the three wear zones is different.There is almost no wear in the dead zone.In the sticking zone,the coating failure is affected by high temperature and high pressure.In the sliding zone,the coating failure is caused by the chip sliding friction on the rake face.The cutting force is obtained through the dynamometer.The results indicate that at low feed rate,the resistance and feed force are bigger than the main cutting force,which is affected by the rebound of the machined surface.The temperature of the free surface of the chip is obtained by the infrared thermal imager.The results indicate that the chip thickness increases with the increase of the feed rate,resulting in no increase in chip free surface temperature.