Investigation Of Coated-Tools With Multi-Consitituent Hard Composite Films Of Gradient-Compositions

In the present work, the (Ti,Al,Zr)N, (Ti,Al,Cr)N and (Cr,Ti,Al,Zr)N multi-constituent hard composite films with gradient-compositions were deposited by multi arc ion plating (MAIP) technology by the aid of controlling the rates of flow of Ar and N2. The Ti-Al binary alloy, the Ti-Al-Zr ternary alloy and pure chromium were adopted as cathodic arc resource targets and the cemented carbide tools (YT15, YG10X) were used as the deposition substrates. The compositions, morphology and phase structure of the films were analyzed by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The surface roughness, the micro-hardness and the adhesive strength between the film and the substrate were measured by Roughness Measuring Instrument, Vickers hardness indentator and Scratch tester, respectively. The cutting tools coated with the three films were tested in the experiments including turning of 45# steel, milling of CrWMn alloy tool-steel and drilling of high-speed steel. The surface morphology of cutting edge and chemical element diffusion were analyzed by using scanning electron microscopy (SEM) and Energy Dispersed Spectroscopy (EDS) after the cutting experiments. The wom surface morphologies of films and the amount of wear of the coated tools were observed and measured by optical microscope and tool-microscope.The research results showed that the (Ti,Al,Zr)N, (Ti,Al,Cr)N and (Cr,Ti,Al,Zr)N multi-constituent hard composite films with gradient-compositions could be obtained by using multi-arc ion plating technology. The as-deposited (Ti,Al,Zr)N, (Ti,Al,Cr)N and (Cr,Ti,Al,Zr)N films exhibited high micro-hardness values even up to 4400HV and very high adhesive strength super to 180N. These films were suitable for the cemented carbide cutting tools with different nameplates and different shapes.It was also showed that the three hard composite films were of the B1-NaCl type face-centered cubic structure. The cutting coated-tools, for example, the turning tools, the milling cutters and the drills, exhibited clearly better mechinability than the uncoated ones. Among the three, the coated-tools with (Cr,Ti,Al,Zr)N film showed the best machinability and the coated-tools with (Ti,Al,Cr)N film were better than the coated tools with (Ti,Al,Zr)N film. The mechinability of the three series coated-tools increased obviously from two times to six times as compared with the uncoated-tools. The three kinds of coated-tools showed the excellent bonding-resistance and the abrasion resistance. The films effectively prevented the tools substrate in direct touch with workpieces materials. To some extent, the overall performance of the cutter substrate was protected by preventing hard particles wear, diffusion wear, oxidation wear and adhesion wear.