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Journal ArticleDOI

Machinability study of pure aluminium and Al–12% Si alloys against uncoated and coated carbide inserts

TL;DR: In this article, an investigation has been undertaken to study the compatibility of cutting materials in dry machining of aluminium and Al-Si alloys, and the results of turning test, SEM pictures and chip morphology investigation of the cutting tool after machining clearly reveal the inefficiency of TiC, TiN, TiB2, Al2O3, and AlON.
Abstract: An investigation has been undertaken to study the compatibility of cutting materials in dry machining of aluminium and Al–Si alloys. Mono or multilayer coated carbide tools with a top coating of TiC, TiN, TiAlN, Al2O3, TiB2, MoS2 etc. on WC–Co inserts already made a major breakthrough in dry machining of ferrous materials. But in contrast dry machining of aluminium and Al-alloys is a great challenge. But wide application of aluminium different parts has increased the need to find out the correct cutting tool. Experimental results of turning test, SEM pictures and chip morphology investigation of the cutting tool after machining clearly reveals the inefficiency of TiC, TiN, TiB2, Al2O3, and AlON in dry machining of aluminium. This is because of the formation of very large amount of metal built-up in both rake and flank surface leading to high magnitude of cutting forces and high roughness of the work-piece during machining. The natural diamond and polycrystalline diamond (PCD) can be used as a cutting tool, when the required shape is attached on the edge/tip for machining non-ferrous materials. But both of them are limited for finishing cut because of high cost. So CVD diamond coated tool is a better option to machine these materials. CVD diamond coated tool was free from built-up edge formation leading to clean cut, low magnitude of cutting forces and improved surface finish of the work-piece. However, performances of the diamond tool depend mainly on adhesion of the diamond coating with the carbide substrate.
Citations
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Journal ArticleDOI
TL;DR: The use of aluminum alloys in manufacturing industry has increased significantly in recent years as discussed by the authors, mainly due to their ability to combine lightness and strength in a single material, and the machining of aluminum alloy has enormously increased in volumetric proportions, so that the chip volume represents up to 80 % of the original volume of the machined material in certain segments of the industry, like aerospace.
Abstract: The use of aluminum alloys in manufacturing industry has increased significantly in recent years. This is because primarily to their ability to combine lightness and strength in a single material. Concomitant to this growth, the machining of aluminum alloys has enormously increased in volumetric proportions—so that the chip volume represents up to 80 % of the original volume of the machined material in certain segments of the industry, like aerospace. In this context, knowledge of the characteristics of machinability of aluminum alloys is essential to provide industry and researchers with information that allows them to make the right decisions when they come to machining this fantastic material. The purpose of this review is to compile relevant information about the characteristics of machinability of aluminum alloys into a single document.

170 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a review of the impact of hole quality on the performance of the Al2024 and Al7075 alloys used in the aerospace industry, focusing mainly on the hole size and circularity error.
Abstract: Despite the growth of composites and other lightweight materials, aluminium alloys remain an attractive choice of the aerospace industry due to their mature manufacturing processes, good resistance to fatigue crack growth and superior damage tolerance. In the aerospace industry, the drilling process is the most challenging among all the other machining process as millions of holes are required for producing riveted and bolted joints in the assembly operation of the aircraft's structures. The major challenges which arise from the drilling of these alloys are characterized by the poor hole quality which might initiate cracks within the airframe structure and reduces their reliability. This results in the rejection of parts at the assembly stage which directly impacts the manufacturing cost. Hence, appropriate selection of tool geometry, tool material and coatings, optimal cutting speed and feed rate, as well as drilling machines, is required to meet the requirement of machined parts. This motivates both academia and industries to further research on the application of drilling operations in the aircraft industry. This review aims to document details on drilling forces, drilling parameters, drill tool geometry, drill materials and coatings, chips formation, analysis of tool wear and hole metrics such as the hole size and circularity error, surface roughness, and burrs formation during the drilling of different aluminium alloys used in the aerospace industry. The focus will be mainly on Al2024 and Al7075 alloys since they are most commonly used and reported in the open literature.

89 citations


Cites background from "Machinability study of pure alumini..."

  • ...[99] reported that aluminium alloys have a higher chemical affinity for materials like TiB2, TiC, Al2O3, TiN, and AlON....

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  • ...Different tool wear mechanism includes flank wear which results from the adhesive and abrasive wear mechanism [99,102]....

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  • ...[99] Roy P, Sarangi S, Ghosh A, Chattopadhyay A....

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Journal ArticleDOI
TL;DR: In this paper, the machining and sustainability characteristics of minimum quantity lubrication (MQL), nanofluids-MQL, Ranque-Hilsch vortex tube MQL (RHVT + MQL), cryogenic MQL as alternative to flood cooling applications in the cutting of light-weight materials are presented.

75 citations

Book ChapterDOI
04 Feb 2011
TL;DR: In this article, the machinability of aluminum alloys is defined by various criteria, such as tool life, surface finish, chip evacuation, material removal rate and machine-tool power.
Abstract: The use of materials with low specific weight is an effective way of reducing the weight of structures. Aluminum alloys are among the most commonly used lightweight metallic materials as they offer a number of different interesting mechanical and thermal properties. In addition, they are relatively easy to shape metals, especially in material removal processes, such as machining. In fact, aluminum alloys as a class are considered as the family of materials offering the highest levels of machinability, as compared to other families of lightweight metals such as titanium and magnesium alloys. This machinability quantifies the machining performance, and may be defined for a specific application by various criteria, such as tool life, surface finish, chip evacuation, material removal rate and machine-tool power. It has been shown that chemical composition, structural defects and alloying elements significantly influence machinability [W Konig et al., 1983]. Thus, with similar chemical compositions, the machinability of alloys can be improved by different treatments. Heat treatments, which increase hardness, will reduce the built-up edge (BUE) tendency during machining [M. Tash et al., 2006]. In the case of dry machining, the major problems encountered are the BUE at low cutting speeds and sticking at high cutting speeds, hence the need for special tool geometries [P. Roy et al., 2008]. It has been shown that high levels of Magnesium (Mg) increase the cutting forces at the same level of hardness [M. Tash et al., 2006], while a low percentage of Copper (Cu) in aluminum alloy 319 decreases the cutting force. Similarly, it has been found that heat treatment of 6061, especially aging, influences the forces only at low cutting speeds, while at high speeds, the influence is negligible because of the low temperature rise seen in the cutting zone [Demir H et al., 2008]. Cutting force is just one among several parameters to be considered for a full assessment of the machinability of metallic alloys, with the others being the tool life, the surface finish, the cutting energy and the chip formation mode. Aluminum alloys are classified under two classes: cast alloys and wrought alloys. Furthermore, they can be classified according to the specification of the alloying elements involved, such as strain-hardenable alloys and heat-treatable alloys. Most wrought aluminum alloys have excellent machinability. While cast alloys containing copper, magnesium or zinc as the main alloying elements can cause some machining difficulties, the use of small tool rake angles can however improve machinability. Alloys having silicon as the main alloying element involve larger tool rake angles, lower speeds and feeds, making

66 citations

Journal ArticleDOI
Liang Wang1, Xuelin Lei1, Bin Shen1, Fanghong Sun1, Zhiming Zhang1 
TL;DR: In this article, the tribological properties of boron-doped and silicon doped diamond films were examined by using a ball-on-plate type rotating tribometer with silicon nitride ceramic as the counterpart in ambient air.

65 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the state of the art in hard coatings for carbide cutting tools including discussion of coating characteristics and applications is presented, as well as a detailed discussion of their application.
Abstract: The majority of carbide cutting tools in use today employ hard coatings because coatings offer proven benefits in terms of tool life and machining performance. Continuing development of the chemical vapor deposition (CVD) coating process, the most widely used technique, has produced complex multilayer coatings tailored for specific applications and workpiece materials. These coatings include alumina layers of different crystal structures, and TiCN layers applied by high- or moderate-temperature (MT-CVD) processes. Over the last decade, coatings applied by physical vapor deposition (PVD) have gained acceptance in applications requiring sharp edges or those featuring interrupted cuts. Originally limited to TiN coatings, the PVD offering now includes TiCN and TiA1N coatings which provide better high-speed performance and increased abrasive wear resistance. In the area of superhard coatings, improvements in deposition processes and coating adhesion have resulted in diamond-coated carbide tools that have begun to play an important role in machining non-ferrous and non-metallic materials. This paper presents the state of the art in hard coatings for carbide cutting tools including discussion of coating characteristics and applications.

199 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the residual stresses can be significantly reduced if the TiB 2 coatings are deposited by magnetron sputtering utilising electrons to enhance adatom mobility on the growing film surface.

109 citations

Journal ArticleDOI
TL;DR: In this article, the influence of experimental variables on process stability and Al 2 O 3 modification and structure was investigated, and it was concluded that the kinetic of the K →α-Al 2 o 3 transformation is affected thereby and results in enhanced wear resistance for high temperature applications of cemented carbide cutting tool inserts.
Abstract: Today, high performance applications of cemented carbide cutting tool inserts demand coatings with enhanced wear resistance Chemical vapour deposited coatings based on Ti(C,N) and Al 2 O 3 are the systems of choice for these applications The influence of experimental variables on process stability and Al 2 O 3 modification and structure was investigated Deposition characteristics of Al 2 O 3 as a function of doping combinations, generated by additional gases (TiCl 4 , BCl 3 ), and deposition temperature are reported The Al 2 O 3 coatings were deposited in the temperature range of 930-1030 °C at atmospheric pressure Doping element concentrations and distribution were investigated by inductively coupled plasma mass spectrometry, energy-dispersive X-ray spectra and scanning transmission electron microscopy Microstrain and substructure were evaluated by high temperature X-ray diffraction analysis and discussed in consideration of doping element type and deposition temperature and phase stability in the application temperature range of 800-1100 °C The investigations have shown that the deposition rates can be enhanced by doping with Titanium The temperature range of K-Al 2 O 3 phase stability during deposition is extended by Boron Ti-and B-doped K-Al 2 O 3 exhibited lower full width half maximum values at temperatures above 1000 °C It was concluded that the kinetic of the K →α-Al 2 O 3 transformation is affected thereby and results in enhanced wear resistance for high temperature applications of K-Al 2 O 3 coated cutting tool inserts

61 citations

Journal ArticleDOI
TL;DR: In this paper, the possibility of magnetron sputtered TiB 2 coatings reducing the ability of aluminium to be transferred to the tool surface has been experimentally evaluated by sliding against an aluminium alloy (AA7075).
Abstract: A major problem in machining aluminium alloys is abrasive wear of the cutting tool due to the presence of oxides and other hard particles in the metal. The strong tendency of aluminium to adhere to the tool and form built-up edges is another problem, which affects the finish of the cut surface. Bulk titanium diboride TiB 2 is hard, and known to have a high chemical resistance when exposed to aluminium. These characteristics make this material an interesting candidate to be applied as a coating on tools aimed at machining aluminium alloys. Polycrystalline diamond (PCD) tools are often used today in operations involving both shaping (removal of large volumes) and surface finishing. However, they tend to produce too rough surfaces. In this paper, the possibility of magnetron sputtered TiB 2 coatings reducing the ability of aluminium to be transferred to the tool surface has been experimentally evaluated by sliding against an aluminium alloy (AA7075). It was found that TiB 2 coatings with relatively low residual compressive residual stress (−0.5 GPa) performed better than a reference TiN coating and uncoated cemented carbide as to the tendency of aluminium pick up. In addition, this TiB 2 coating was more resistant to detachment and chemical wear as compared to highly stressed TiB 2 (−6.1 GPa).

59 citations

Journal ArticleDOI
TL;DR: In this paper, the synthesis, microstructures and properties of γ-aluminum oxynitride (AlON) were analyzed and the Gibbs energy of AlON with different compositions and temperatures were evaluated.
Abstract: This paper deals with the synthesis, microstructures and properties of γ-aluminum oxynitride (AlON). The thermodynamic properties of AlON were analyzed and the Gibbs energy of AlON with different compositions and temperatures were evaluated. Based on thermodynamic studies, AlON has been synthesized. The microstructures, mechanical properties and oxidation resistance of the synthetic AlON have been examined and discussed.

56 citations