Study On The Fabrication Of Diamond-like Carbon Film And Its Performance Of Cutting Aluminum Alloy

Under the pressure of environmental protection and manufacturing cost, dry machining becomes the developmental direction of machining aluminum alloy, which demands for high-performance cutting tools. In recent years, much attention has been paid on the Diamond-Like Carbon coatings. In this paper, DLC coatings were deposited on the HSS (W6Mo5Cr4V2) substrate and carbide end mill (YG3) by the technology of Circular Arc and Linear Ion Source separately. The properties of DLC coatings were characterized by CSM Micro-Scratching Tester,3-D Surface Measurement System, Raman Spectrometer and Physical Properties Measurement System. Study on the friction and wear behavior between DLC coating and aluminum by M-2000Friction and Wear Tester. Dry milling aluminum alloy tests were carried out on Turret Milling Machine. The friction and wear behavior between DLC and aluminum friction pair, the dry machining performance and mechanism of DLC coatings were discussed. The conclusion can be made as following:1. The sp3content of DLC-1deposited by Circular Arc and DLC-2deposited by Linear Ion Source were68%and53%separately. By means of one-dimensional steady heat conduction model, the thermal conductivity of DLC-1and DLC-2were4924.2W·(m· K)-1and1657.4W·(m· K)-1in the temperature of200K separately. The surface roughness of DLC-1and DLC-2were0.17μm and0.062μm separately. The crack propagation resistance value of DLC-1and DLC-2were45.67and80.85separately.2. The friction and wear process between DLC coating and aluminum can be divided into three stages:I. Initial stage, which is without aluminum adhesion and shows ultro-low dry friction coefficient; Ⅱ. Thickness reduction and partial rupture of DLC coatings, which leads to few amount of aluminum adhered onto the friction counterpart; Ⅲ. With the accumulation of aluminum smearing over the counterpart, the friction behavior occurs indeed between aluminum smearing layer and aluminum friction pair, leading to the incredibly increased dry friction coefficient.3. During dry friction, DLC coatings did not form the graphite transferred film, but formed10-20μm carbon spalling particles on the surface of the friction pair in the simulated environment of dry machining aluminum alloy. The higher the sp3content of DLC coatings, the less amount of aluminum transferring, longer wear life and lower dry frictioncoefficient in the friction and wear process.4. Secondary transfer of adhesive aluminum and Build-up Edge are the main influencefactors for dry machining aluminum alloy. DLC coating can greatly improved themachining accuracy, machining stability and dry milling life of carbide end mill in drymilling aluminum alloy. The sp3content of DLC coating was the key to the wettabilitywith aluminum alloy, internal friction coefficient, cutting heat and tool-chip interfacetemperature in dry machining aluminum alloy. DLC coatings can achieve better drymachining aluminum alloy performance with higher sp3content.