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The purpose of this study is to design and develop a new functional coating system for aerospace AL7075-T6 alloy that would evaluate the mechanical properties of the coating.

This paper outlines the scratch adhesion characterisation of Cr/CrAlN coating using a combination of radio frequency (RF) and direct current (DC) physical vapour deposition (PVD) magnetron sputtering. The surface morphology, microstructure and chemical composition of the Cr/CrAlN film were evaluated by optical microscopy (OM), field emission scanning electron microscopy (FESEM) integrated with energy-dispersive X-Ray spectroscopy (EDX) and atomic force microscopy (AFM). The film-to-substrate adhesion was measured by a scratch test machine manufactured with a detection system, motorized stages, penetration depth sensors, optical microscope and tangential frictional load sensors.

The AFM and ultra-micro hardness results showed an increase in surface roughness to about 20 per cent and hardness to about 74 per cent. Moreover, the film-to-substrate adhesion strength of 1,814 mN was obtained with PVD deposition process.

The main limitation of this work is caused by PVD deposition process. Besides, surface defects such as pinholes contribute to a decrease in adhesion strength.

The higher hardness of CrAlN coating is used to improve the properties of softer aluminium substrates. This hardness prevents ploughing-induced wear and provides greater adhesion strength by preventing coating delamination.

Until now, CrAlN is coated only on ferrous alloys. It has not yet been tried on aluminium alloys. Moreover, coating functionality depends on higher adhesion and failure mechanisms involved in the film-to-substrate system, which is significant in aerospace applications.

This paper aims that optimization parameters depending on machining processes examine to define for the milling process of AL 6061-T6 aluminum alloy used in the aviation industry.

The Taguchi method was used to study the optimal parameters. Furthermore, the effects of machining parameters on surface roughness were also evaluated by performing variance analysis. Optimum parameter levels were determined by Signal/Noise analysis.

It was determined that the parameter levels that optimize the surface roughness were “4000 rev/min for the rotational speed of the cutting tool, 0.4 mm for the cutting depth and the optimum value for the feedrate 500 mm/min.”

It is limited by the precision of the manufacturing processes, the desired geometry and the exactness of the measurement make the machine productivity valuable in the production of parts.

By improving the optimal production parameters, reducing part production costs and waste amount in aviation has been seen as an important gain.

Improving production methods and optimization parameters in production technologies will ensure the minimization of loss and waste. These developed parameters with optimizing the surface roughness will add value in this context.

It was determined that the parameter levels that optimize the surface roughness of aluminum considering manufacturing processes. Especially as process parameters, optimum feed rate has been developed for effective rotation speed and cutting depth for cutting tools.

The purpose of this study is to design and develop new spiral head projectiles undergoing ballistics impact.

The introduction of the rifled barrel in firearms made projectile spin during its flight path. The central translational velocity (impact velocity) is one parameter to defeat/penetrate the target in the penetration process. Another important parameter considered to be the shape of the projectile. Many types of projectile shapes have been designed to defeat the target. In the recent years, ogival nose shape is one of the well-known projectile shapes in use abundantly. The present research is made to design the nose shape so as to use the spin during the penetration of target effectively. In this study, a new spiral head projectile shape is proposed and designed, which uses the rotation of projectile (spin) for penetrating the Al7075-T6 target. When the ogive and new spiral head projectile is impacted on Al 7075-T6 target of 12.5 mm, 18 mm thicknesses at ordnance velocities, the residual velocity is evaluated numerically using ANSYS/Explicit Dynamics at normal impact condition. Two projectile materials, steel 4340 and tungsten alloy, are used as projectile materials. Along with the translational velocity, rotation velocities (spin rate) 13,000, 26,000 and 52,000 rad/s also provided to projectile. The residual velocities verses spin rate are plotted for different spiral angle projectiles for impact velocities 1,000–1,500 m/s, at normal impact conditions on the Al 7075-T6 target. Compared with the ogive nose projectile, the proposed new spiral head projectile made of tungsten alloy is significantly effective.

Spiral head projectile having tungsten alloy material gives encouraging results at 12.5 mm target thickness. The new spiral head projectile is damaged partially. At 18 mm target thickness impact conditions, it is observed that the projectile head is completely damaged. The effectiveness of spiral head projectile on a target plate thickness of 18 mm is considered to study the impact condition.

All the above results need to be experimentally verified. However, the basic numerical model used in the present study, i.e. the basic ogive nose numerical model with only translational energy, is well validated with penetration theory available in literatures.

The designed new spiral head projectile is only effective with tungsten alloy material within considered design parameters. For steel 4340 material, the spiral head projectile is less effective than the ogive nose projectile. In tungsten alloy projectiles, by observing all considered spiral angles, 30-degree spiral angle projectile gives the best performance at most of the considered impact velocity conditions.

The proposed research outputs are original, innovative and, have lot of importance in defence applications particularly in arms and ammunitions.

Niobium Nitride (NbN) was interesting material for its applications in the medicinal tools or tools field (corresponding to saline serum media) as well as in mechanical properties. The aim of this work was depositing NbN thin films on two types of substrates (stainless steel (SS304) and silicon (100)) using plasma technique at varied powers (100–150 W).

DC magnetron sputtering technique at different powers were used to synthesis NbN films. Film structure was studied using X-ray diffraction (XRD) pattern. Rutherford elastic backscattering and energy dispersive X-ray were used to examine the deposited film composition. The films morphology was studied via atomic force microscopy and scanning electron microscopy images. Corrosion resistance of the three NbN/SS304 films was studied in 0.9% NaCl environment (physiological standard saline).

All properties could be controlled by the modification of DC power, where the crystallinity of samples was changed and consequently the corrosion and microhardness were modified, which correlated with the power. NbN film deposited at higher power (150 W) has shown better corrosion resistance (0.9% NaCl), which had smaller grain size (smoother) and was thicker.

The NbN films have a preferred orientation (111) matching to cubic structure phase. Corrosion resistance was enhanced for the NbN films compared to SS304 substrates (noncoating). Therefore, NbN films deposited on SS304 substrate could be applied as medicinal tools as well as in mechanical fields.

The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail.

In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components.

It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively.

It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials.

The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials.

This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

This study aims to investigate the effect of microtextured tools on the geometric morphology of serrated chips, and further improve the cutting performance of polycrystalline cubic boron nitride (PCBN) tool and extend the tool life and the surface quality of the machined surface.

A three-dimensional finite element cutting model of hardened steel AISI D2 with microtextured PCBN tools were established using the finite element software Abaqus, and cutting tests were carried out. Furthermore, the stress distribution in the primary deformation zone was investigated based on the triaxiality of stress, and the influence of microtexture on the geometric morphology of serrated chips and crack development was researched.

The results show that compared with nontexture tools, elliptical pits and wavy grooves microtexture tools have lower serrated degree Gs, higher serrated frequency f per unit length and more miniature serrated step Pc. The serrated phenomenon is intensified because the tensile stress zone of chips generated by nontextured tools is longer than that of elliptic pits and wavy grooves microtexture tools. Simultaneously, the maximum value of triaxiality in the tensile stress zone achieved by nontexture tools is larger than that of the two microtexture tools, and chips obtained by nontextured tools are more susceptible to propagation fractures.

This paper mainly studies the effect of microtexture on chip microgeometry, which is relatively little studied at present. At the same time, this paper has a certain engineering significance for PCBN tool turning hardening steel.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0149/

The purpose of this paper is to determine the influence of the shape of a cutting edge on high-performance milling high-performance cutting. The main purpose of the test was to determine the possibility of increasing the efficiency of machining AlZn5.5CuMg alloy, which is used mainly for the thin-walled structural aerospace components.

In all, eight cutters for machining aluminum alloys with different shape of the cutting edge (1 – continuous, 4 – interrupted, 3 – wavy) were tested. The influence of different shapes of a cutting edge on cutting force components and vibration amplitude was analyzed. Furthermore, the impact of a chip breaker on the form of a chip was determined.

The conducted test shows that using discontinuous shapes of a cutting edge has impact on the reduction of the cutting force components and, in most cases, on the increase of vibration amplitude. Moreover, using a chip breaker caused significant chip dispersion. The optimal shape of a cutting edge for cutting AlZn5.5CuMg alloy is fine wavy shape.

Potential practical application of the research is high-performance milling of AlZn5.5CuMg alloy, for example, production of thin-walled aerospace structural components.

Different shapes of a cutting edge during high-performance milling of aluminum alloy were tested. The influence of tested geometries on HPC process was determined. The most favourable shape of a cutting edge for high-performance cutting of AlZn5.5CuMg alloy was determined.

This study aims to obtain the lowest surface roughness (Ra) and drill bit adhesion values (AV) depending on the change in control factors (cutting speed-Vc, feed rate-f and drill bit-D) during drilling of the Al 5083 H116 alloy. Low roughness values increase the fatigue strength of the final part and affect tribological properties such as lubrication and friction. In the machining of ductile materials, the AV increases the Ra value and negatively affects the tool life.

Drilling tests were conducted using Taguchi L16 orthogonal array. The experimental measurement findings for Ra and AV were adjusted utilizing the Grey Relational Analysis (GRA), the Response Surface Method (RSM) and Artificial Neural Networks (ANN) to generate prediction values. SEM detected drill-tip adhesions and chip morphology and they were analyzed by EDX.

Ra and AV increased as the f increased. Vc affects AV; 86.04% f on Ra and 54.71% Vc on AV were the most effective control parameters. After optimizing Ra and AV using GRA, the f is the most effective control factor. Vc: 120 m/min, f: 0.025 mm/rev and D2 were optimal. ANN predicted with Ra 99.6% and AV 99.8% accurately. Mathematical models are obtained with RSM. The increase in f increased AV, which had a negative effect on Ra, whereas the increase in Vc decreased the adhesion tendency. With the D1 drill bit with the highest flute length, a relatively lower Ra was measured, as it facilitates chip evacuation. In addition, the high correlations of the mathematical models obtained indicate that the models can be used safely.

The novelty of this study is to determine the optimum drilling parameters with GRA and ANN for drilling the necessary holes for the assembly of ammunition wing propulsion systems, especially those produced with Al 5083 H116 alloy, with rivets and bolts.

Milling is a flexible creation process for the manufacturing of dies and aeronautical parts. While machining thin-walled parts, heat generation during machining essentially affects the accuracy. The workpiece temperature (WT), as well as the responses like material removal rate (MRR) and surface roughness (SR) for input parameters like cutting speed (CS), feed rate (F), depth-of-cut (DOC), step over (SO) and tool diameter (TD), becomes critical for sustaining the accuracy of the thin walls.

Response surface methodology was used to make 46 tests. To convert the multi-character problem into a single-character problem, the weightage was assessed using the entropy approach and the grey relational coefficient (GRC) was determined. To investigate the connection among input parameters and single-objective (GRC), a fuzzy mathematical modelling technique was used. The optimal performance of process parameters was estimated by grey relational entropy grade (GREG)-fuzzy and genetic algorithm (GA) optimization.

SR was found to be a significant process parameter, with CS, feed and DOC, respectively. Similarly, F, DOC and TD were found to be significant process parameters with MRR, respectively, and F, DOC, SO and TD were found to be significant process parameters with WT, respectively. GREG-fuzzy-GA found more suitable for minimizing the WT with the constraint s of SR and MRR and provide maximum desirability of 0.665. The projected and experimental values have a good agreement, with a standard error of 5.85%, and so the responses predicted by the suggested method are better optimized.

The GREG-fuzzy-GA is a new hybrid technique for analysing Inconel625 behaviour during machining in a 2.5D milling process.

The purpose of this paper is to determine the optimum level of geometrical parameters such as helix angle, nose radius, rake angle and machining parameters such as cutting speed, feed rate and depth of cut to arrive minimum surface roughness and tool wear during end milling of Al 356/SiC metal matrix composites (MMCs) using high speed steel end mill cutter.

L27 Taguchi orthogonal design with six factors and three levels is employed for conducting experiments. Analysis of variance (ANOVA) is carried out using Minitab16 software to find the influence of each input parameter on output performance measure. Grey-fuzzy logic multi optimisation algorithm is used to find the optimum level of the input parameters for minimum surface roughness and tool wear simultaneously.

It is found that optimal combination of helix angle 40°, nose radius 0.8 mm, rake angle 12°, cutting speed 90 m/min, feed rate 0.04 mm/rev and depth of cut 1.5 mm have generated minimum surface roughness of 0.4063 µm and tool wear of 0.0375 mm. From ANOVA analysis, it is found that cutting speed influence is more on output performance followed by helix angle and rake angle compared with other machining and geometrical parameters.

The influence of tool geometry during end milling of MMC using Grey-fuzzy logic algorithm has not been explored previously.