Shift of wear balance acting on CVD textured coatings and relation to workpiece materials

Bejjani, Roland; Odelros, Stina; Öhman, Sebastian; Collin, M.

doi:10.1177/1350650120926781

Cited by 15 publications

(7 citation statements)

References 33 publications

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“…While the tungsten and carbon distributions are consistent between both inserts, there is a clear difference in the distribution of iron (Fe).It is remarkable that the areas of low Fe concentration observed in Figure5.10 coincide with the areas of high abrasion seen in the SEM images in Figure5.9. A similar phenomenon was observed by Bejjani et al on the surface of coated tools where abrasion creates grooves on the surface of the tool which enhance adhesion of workpiece material[73]. During cutting, adhered particles are often detached, removing a volume from the insert in the process, which explains the low Fe at the abrasion region.…”

supporting

confidence: 68%

“…The adhered layer, shown in Figure 4.8, is caused by Ti64 particles that adhere to the cutting edge, and are then plastically deformed onto the tool rake face by the effect of high-pressure flowing chips [73]. While this benefits the tool by forming a layer to protect the substrate from abrasive wear, it actually promotes crater wear by activating the diffusion mechanism [73].…”

Section: Cryogenic Effect On Tool Wearmentioning

confidence: 99%

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Modelling the cryogenic environment aided by CFD & FEM to provide optimized solutions for unconventional manufacturing of aerospace alloys. (c2020)

Salame¹

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The modern manufacturing industry needs to meet the growing demands of aerospace production, while adhering to increasingly strict environmental and sustainability constraints. Cryogenic machining is steadily gaining traction as an eco-friendly unconventional machining method, effectively improving the machinability of the workpiece by cooling and lubricating the cutting process. The increased demand in the aerospace industry requires using higher cutting speeds and feeds, which adversely affect the machinability of the already difficult-tomachine aerospace alloys. This makes the optimization of the cryogenic manufacturing process critical to ensuring a good machinability and a high-quality product. This research investigates the optimization of cryogenic manufacturing of aerospace materials such as titanium alloy Ti-6Al-4V and low carbon steel A36. The optimization varies the cryogenic nozzle position in terms of separation distance from the tool-chip interface and the inclination angle from the vertical to determine the combination that leads to the minimum cutting forces. The study begins with a Computational Fluid Dynamics (CFD) model, aided by the results of Finite Element Modeling (FEM), to simulate the cryogenic environment for each of the nozzle positions and determine the optimal cooling effect. Cryogenic turning tests are then conducted by varying the same nozzle positions to measure the cutting forces in each case and compare them to dry turning. For the case of optimal cryogenic turning, tool wear and surface integrity are compared to dry turning using optical microscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). It is shown that the nozzle position with the smallest separation distance and smallest orientation angle from the vertical leads to the biggest reduction in cutting temperatures as well as cutting forces, and a correlation is drawn between the cryogenic cooling effect and cutting forces. The dominant parameter affecting machining process the most is the separation distance. The results from the CFD and FEM simulations are used to provide a better understanding of the cryogenic effect on the machining process in terms of cutting temperatures, convection coefficients, phase composition and pressure near the tool-chip interface. In addition, a reduction in workpiece surface roughness and tool wear are observed for the case of optimal cryogenic machining, with adhesion being the dominant wear mechanism observed in both conventional and cryogenic turning. This research proves the importance of optimizing the nozzle position in the cryogenic manufacturing system, which has a positive effect on the machinability of difficult-to-machine materials. Using the optimized cryogenic system presents a practical solution to improve the productivity in the aerospace industry and meet the increasing demand in an eco-friendly and sustainable way.

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supporting

confidence: 68%

Section: Cryogenic Effect On Tool Wearmentioning

confidence: 99%

Modelling the cryogenic environment aided by CFD & FEM to provide optimized solutions for unconventional manufacturing of aerospace alloys. (c2020)

Salame¹

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“…The void created by microchipping, under the effect of high cutting pressure from the flowing chips promotes adherence of workpiece material which are then plastically deformed onto the tool and appear as smearing, as observed in Figure 12 . The process can be repeated for different locations, and results in more signs of adherence on the insert due to the effect of flowing chips [ 22 ]. Adhesion and diffusion work hand in hand to accelerate the wear, where diffusion can deplete the carbon from the tool matrix, making it easier for the flowing chips to pull out the tungsten particles that are no longer anchored [ 23 , 24 ].…”

Section: Resultsmentioning

confidence: 99%

An Experimental and Finite Element Approach for a Better Understanding of Ti-6Al-4V Behavior When Machining under Cryogenic Environment

2021

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Due to increasing demand in manufacturing industries, process optimization has become a major area of focus for researchers. This research optimizes the cryogenic machining of aerospace titanium alloy Ti-6Al-4V for industrial applications by studying the effect of varying the nozzle position using two parameters: the nozzle’s separation distance from the tool–chip interface and its inclination angle with respect to the tool rake face. A finite element model (FEM) and computational fluid dynamics (CFD) model are used to simulate the cryogenic impingement of cryogenic carbon dioxide on the tool–workpiece geometry. Experiments are conducted to evaluate cutting forces, tool wear, and surface roughness of the workpiece, and the results are related to the CFD and FEM analyses. The nozzle location is shown to have a significant impact on the cutting temperatures and forces, reducing them by up to 45% and 46%, respectively, while the dominant parameter affecting the results is shown to be the separation distance. Cryogenic machining is shown to decrease adhesion-diffusion wear as well as macroscopic brittle chipping of the cutting insert compared to dry turning, while the workpiece surface roughness is found to decrease by 44% in the case of cryogenic machining.

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“…The most prevalent applications can be found in the automotive, railway, and aerospace industries. [2,3] It is important to reduce the mortality rate caused by car crashes in the automotive industry. When it comes to passengers' safety, some critical crashworthy elements must be considered to design proper energy absorbers.…”

mentioning

confidence: 99%

4D Metamaterials with Zero Poisson's Ratio, Shape Recovery, and Energy Absorption Features

Hamzehei

Serjouei

et al. 2022

Adv Eng Mater

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Crashworthiness is the ability of the materials or structures to absorb impact energy through plastic deformations, friction, fracture, shear, bending, and even torsion. [1] Energy absorbers have been extensively used for different applications. The most prevalent applications can be found in the automotive, railway, and aerospace industries. [2,3] It is important to reduce the mortality rate caused by car crashes in the automotive industry. When it comes to passengers' safety, some critical crashworthy elements must be considered to design proper energy absorbers. The most vital item could be the initial reaction force caused by hitting an external object. [4] The lower the initial reaction force, the safer the occupants might be. A vehicle contains structural elements like rockers, pillars, and bumpers. Among these elements, the front bumper plays a vital role when it comes to energy absorption and is the most effective parameter for vehicle safety and occupants. The front bumper usually absorbs more than half of the kinetic energy during a car crash. [4] This is the main reason for magnifying the existence of high-performance energy absorbers Distinct from the initial reaction force, the crashworthy designers have been considering various main criteria for an ideal energy absorber, including high energy absorption performance, stability, and safety. Consequently, some design approaches such as gradual energy absorption (GEA), piecemeal energy absorption (PEA), and conventional energy absorption (CEA) have been proposed. [5][6][7] The absorbers designed based on the PEA and GEA approaches show different peak force levels in force-displacement relation, whereas the CEA-based absorbers show a peak force level in their forcedisplacement relation. Xu et al. [5] proposed a structure exhibiting the GEA for subway vehicles. The proposed energy absorber exhibits multistiffness behavior under the impact, showing different peak force levels as well. Afterward, the concept of piecemeal energy absorption (PEA) was introduced by Esa et al. [6] . The PEA concept is similar to the GEA concept. Due to the flexibility of the PEA concept over the GEA, this concept is extended to diverse applications. The PEA strategy provides lower damages under low-velocity impact and higher energy absorption capacity under high-velocity impact. Apart from the GEA and PEA concepts, most energy absorbers possess a CEA response. [7] The CEA response means a gradual increase in initial reaction forces under the impact and then the fluctuations in crushing forces are caused by overcoming the energy absorber's yield strength.

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Shift of wear balance acting on CVD textured coatings and relation to workpiece materials

Cited by 15 publications

References 33 publications

Modelling the cryogenic environment aided by CFD & FEM to provide optimized solutions for unconventional manufacturing of aerospace alloys. (c2020)

Modelling the cryogenic environment aided by CFD & FEM to provide optimized solutions for unconventional manufacturing of aerospace alloys. (c2020)

An Experimental and Finite Element Approach for a Better Understanding of Ti-6Al-4V Behavior When Machining under Cryogenic Environment

4D Metamaterials with Zero Poisson's Ratio, Shape Recovery, and Energy Absorption Features

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