Preparation And Cutting Performance Of ZrTiN Coated Tools

The introduction of two transition metal in ternary coatings, combined with the mechanism of solid solution strengthening which makes the coatings have better properties than the binary coatings in hardness, adhesion, wear resistance and elevated temperature oxidation resistance. A series of new ZrTiN coated tools were successfully developed on the basis of this theory, and its preparation process, physical and mechanical properties, cutting performance, wear behaviors and mechanisms were studied systematically.The ZTG(ZrTiN/ZrTi/Ti+YT15), ZTF(ZrN/TiN/Ti+YT15) and ZT(ZrTiN+YT15) three coatined tools were prepared on YT15 substrates with pulsed bias assisted with arc ion plating technique combined and ion bomdardment. The coated tools'hardness, adhesion strength and thickness influenced by the titanium and zirconium targets' current, substrate bias, deposition temperature, deposition time and nitrogen flow were systematically studied. The optimal preparation processes were optimized. For ZTG coated tools:Zr target current is 110 A, Ti target current:70 A, nitrogen flow:140 sccm, substrate bias:250 V, deposition temperature:200℃, deposition time:75 minutes, the substrate bias for transition layer:150 V and deposition time of the layer:5 minutes; for ZT coated tools:Zr target current:110 A, Ti target current:70 A, nitrogen flow:100 sccm, deposition time:75 minutes, deposition temperature:200℃, the substrate bias: 250 V; for ZTF coated tools:Zr target current:90 A, Ti target current:80 A, nitrogen flow rate:140 sccm, deposition time:75 minutes, deposition temperature:200℃, the substrate bias:250 V.A series of ZrTiN coated tools' cutting performance were studied by testing, and compared with TiN coated tools and uncoated YT15 tools. The results showed that three components of cutting force increased as the cutting speed increased, according to the size of the cutting force, they can be arranged in the order of ZTG <ZTF<ZT<TN<YT15 under the same cutting conditions; The cutting temperature was affected by cutting speed most significant, according to the size of the temperature, they can be arranged in the order of ZTF<ZTG<ZT<TN<YT15 under the same conditions. Surface roughness affected by cutting speed more significant than cutting depth and feed rate. Five tools' machining surface roughness can be arranged by descending order as YT15>ZTF>ZT>TN>ZTG under same cutting parameters.The ZrTiN series of coated tools' wear performance and mechanism were studied by testing, and compared with TiN coated tools and YT15 tools. It is indicated that the rate of flank wear in descending order is:ZTG<TN<ZTF<ZT<YT15. The ZrTiN series of coated tools' flank wear focused on adehesive wear, border wear, the rake face wear focused on coating spalling and micro-chipping. For YT15 tools, they were mainly adehesive wear. Finite simulation were used to study tools' stress and temperature, it was found that ZrTiN coating can significantly reduce cutting temperature and stress of tools. The wear origins of tools were the place where the maximum temperature and stress of tools centralized.