Papers by Keyword: TiAlN

Abstract: Material transfer is a critical tribological issue in aluminum forming processes, particularly at high temperatures. Although applying PVD or CVD coatings on the forming tool surface could be a solution to alleviate the material transfer issue, selecting an appropriate coating with sufficient tribological performance is still a challenging task. This paper aims to evaluate the tribological performance of AlCrN and TiAlN coatings against 6082-T6 aluminum alloy under dry contact conditions at 400°C by using a process centered approach. The methodological approach implies: 1. pre-processing to assess the contact conditions to be simulated and prepare the experimental samples, 2. processing where the friction tests are performed, and 3. post-processing in which test results are analyzed in terms of coating performance. The warm and hot upsetting sliding test (WHUST) is used as a tribometer in the processing step. A scaled-down version of the existing WHUST is developed to integrate into the heating chamber of Bruker UMT TriboLab for precise control of the specimen and contactor temperatures. Numerical simulation is applied to identify the WHUST parameters in the pre-processing step to reproduce severe contact conditions from the industrial forming processes. The post-processing step includes the identification of Coulomb’s coefficient of friction (COF) and the surface analysis with quantitative and qualitative techniques.

Abstract: This research work is based on the machinability of an Inconel 800 alloy using TiAlN-coating and TiAlN-TiN-coating tools. In the CNC VMC Face milling process feed, depth of cut (DoC), and cutting speed consider input variables and surface roughness, Tool wear is measured for all machining conditions. To enhance the machining conditions a Taguchi L9 Design of Experiment was created. ANOVA analysis was used to identify the important variables influencing Flank wear (tool wear) and surface roughness. The signal-to-noise ratio for the ideal cutting combination was identified by evaluating the optimum surface roughness and tool wear. for the effect of coating, a comparison was done between the findings obtained using both TiAlN-coated and TiAlN-TiN tungsten carbide-coated tools. The best optimum surface roughness and tool wear of the experiment conducted under machining with TiAlN-TiN coated carbide tool resulted in .3433 µm and 128 µm respectively.

Abstract: The paper outlines two approaches (the ANSYS finite element modeling and the differential scheme of the self-consistency method) to model the mechanical properties of TiAlN multilayer coatings. To validate the experimental results, these findings were compared with the nanoindentation test results for single and multilayer coatings. This work has revealed the effect of Ti/Al ratio on the mechanical properties of multilayer coatings. The given approaches could be applied to calculate, with an acceptable margin of error, the mechanical properties of TiAlN multilayer coatings.

Abstract: In this study we determined average residual stresses in hard nitride PVD AlCrN, TiAlN and TiCN coatings through simultaneous measurement of length variation in thin-walled tubular substrates and of the curvature of plate substrates. A device for measurement of the length of the tube was developed. Inside the depositing chamber the tube and the plate were fixed parallel in the relation to the axis of the rotating cathode. One batch of plate samples was produced by deposition on front surface (facing the cathode) and the other batch, by deposition on back surface (with back to the cathode). The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM). The thicknesses of the coatings deposited on front and back surfaces of the plates and on the tube were significantly different. The values of average compressive residual stresses, determined by both methods, were very high irrespective of coating thickness. It was found that the values of compressive residual stresses in the coating were dependent on the shape of the substrate and on its position in the relation to the axis of the rotating cathode.

Abstract: Titanium aluminum nitride (TiAlN) thin films were deposited by reactive DC magnetron co-sputtering technique on Si substrate. The effect of deposition time on the structure of the TiAlN films was investigated. The crystal structure, surface morphology, thickness and elemental composition were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) technique, respectively. The results showed that, all the as-deposited films were formed as a (Ti,Al)N solid solution. The as-deposited thin films exhibited a nanostructure with a crystallite size of less than 30 nm. The film thickness increase from 115 nm to 329 nm, while the lattice parameter decrease from 4.206 Å to 4.196 Å, with increasing of the deposition time. Cross section analysis by FE-SEM showed compact columnar and dense morphology as a result of increasing the deposition time. The elemental composition of the as-deposited films varied with the deposition time.

Abstract: Engineering industries are currently using many tool materials such as ceramic,carbide, high speed steel, Cubic Boron nitride and diamond. In most of the small scale industries, the lathe machines are consuming High Speed Steel (HSS) Tool. The HSS tools are easily available and cheapest one. In this present investigation, the Tungsten HSS Single point cutting tool was taken as substrate material. Two substrate HSS Tools were coated with two different combinations of TiAlN composite material using Physical Vapour Deposition coating technique. The surface roughness and hardness were determined for the tools in same condition. The tools were used in lathe machine in same operating condition. The weights of the tools were checked using standard equipment after each machining trials. The loss of tool weight for each trial was determined and the percentage of weight loss was calculated. The life of the Titanium Aluminium Nitride (Ti 70% , Al 25%) coated tool increased by 3.74 times than uncoated tool. The life of the Titanium Aluminium Nitride (Ti 55% , Al 35%) is increased by 2.71 times than uncoated HSS tool.

Abstract: Manufacturing industries are presently using many tool materials, such as high speed steel, carbide tool and diamond tools etc. The most widely and commonly used tool in the engineering industries is high speed steel (HSS). The HSS tools are the cheapest and reliable for medium and small scale industries. In this work, the HSS single point cutting tool is taken as substrate material and coated with two different combinations of TiAlN composite coating using Physical vapour deposition (PVD) technique. Also, Tool life was calculated and compared with uncoated HSS tool. The hardness and surface roughness value for both the tools have been taken under same condition. The loss of weight in the tool after machining has been weighed using standard equipments. The differences have been closely observed with sufficient trials and find out the loss in weight in both the tools. The weight loss percentage was calculated after proper machining trials. The tool life of the Titanium Aluminium Nitride (Ti 70%, Al 25%) coated tool has been increased by 3.74 times than that of uncoated tool. The surface finish for TiAlN (Ti 70%, Al 25%) coating is better than the uncoated tool. The PVD coated tools having better performance comparing with uncoated HSS tool.

Abstract: For better selection of coated cutting tools, TiAlN (Ti₅₀Al₅₀N) and CrAlN (Cr₅₀Al₅₀N) coatings were deposited onto ball-nose and square end mills using arc evaporation, and their cutting performances were evaluated using steel workpieces of various hardnesses. In particular, cutting tests were performed on three types of workpieces, made from S50C, SKD61, and SKD11 steels, having Brinell hardness numbers of HB220, HRC40, and HRC60, respectively. The results of the cutting experiments were elucidated and discussed in terms of the mechanical properties and anti-oxidation resistances of the different coatings. The results revealed that TiAlN-coated square end mills at high cutting speeds (V = 200 m/min ) had superior performance when used on steels with high hardness (SKD11), whereas CrAlN-coated ball-nose end mills were superior when used on low hardness steel (S50C). Therefore, CrAlN-coated ball-nose end mills are concluded to be suitable for the machining of low hardness steels, whereas TiAlN-coated square end mills are preferable for the machining of high hardness steels (SKD11).

Abstract: High speed cutting is an important means to improve the efficiency and the quality of machining mold steel, but the tool wear is one of the key factors restricting the increase of the cutting speed, leading to higher requirements for cutting tool materials. At present the researches of high-speed cutting of mold steel are mainly on the hardness mold steel, but less on P20 mold steel which hardness is 30-42HRC. This paper mainly studies the effect of cutting speed on wear property of TiAlN PVD coated tools when high-speed milling of P20 mold steels. The experiment was conducted using two different high cutting speeds under dry condition, 320m/min and 500m/min. Wear characterization of the rake and the flank surfaces as well as the collected chips were performed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). It was found that at high speeds, the dominant wear mechanisms were oxidation wear and diffusion wear, followed by adhesive wear and melt wear; as the cutting speed increased, the wear surface area of rake face will be closer to the main cutting edge.

Abstract: Titanium is a hard-to-machine material. An improvement in tool life via advanced tool coating materials can lead to higher productivity of titanium. In this study, a Grade 5 Ti workpiece was milled using a diamond-like carbon coated (ta-C) cutting tool and its performance compared with the standard TiAlN coated endmill. It was found that a ta-C coated tool experienced higher cutting forces than the TiAlN coated tool; however, it showed slower rate of tool wear indicating better tool life and the possibility of achieving higher metal removal rates. Hence, it was concluded that the ta-C coated cutting tool performed better than the standard TiAlN coated tool.