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Electrical discharge machining (EDM) is well-known for its credibility in the processing of advanced materials, which are electrically conductive. The strenuous effort associated with machining of Ti6Al4V (Ti64) using conventional methods, and its low tribological behavior, present an immediate need to develop solutions to monitor and improve the compatible techniques such as EDM.

The present work includes following: monitoring the ED process parameters, namely, current (I) and pulse on time (T_on), in controlling the material removal rate and surface roughness (R_a and S_a) for development of tribo-adaptive surfaces; and investigation on the role of oxides pertinent to the tribo-behavior of Ti64 (bare and EDMed) surfaces.

The tribological behavior of Ti6Al4V surfaces got remarkably improved through ED machining, which points to the credibility of the process to establish itself as a surface alloying technique. The recast layer (RL, alloyed matrix) acted as a protective coating; stable enough to assist the developed tribo-oxides such as TiO and Ti₈O₁₅ in rendering improved sliding performance at load = 50 N and speed = 0.838 ms⁻¹.

The surface modification through ED machining was experimentally proven to improve the wear behavior of Ti6Al4V surfaces.

The purpose of this study is to investigate the effect of electron beam surface melting (EBSM) on the properties of Plasma Transfer Arc (PTA) deposited Stellite 12 hardfacing.

For this purpose, structural characterization and dry sliding wear tests have been conducted on the hardfacings at room temperature. The wear tracks formed on the surfaces of the hardfacings were examined by a stylus-type profilometer and a scanning electron microscope.

Refinement of the matrix and the carbides following EBSM process led to about 15 per cent increment in hardness as compared to PTA state. Despite an increase in the surface hardness, EBSM’ed hardfacing exhibited about 50 per cent lower sliding wear resistance than PTA hardfacing against alumina ball. According to the worn surface examinations, reduction in the wear resistance of Stellite 12 after EBSM process has been associated with the extensive refinement of the carbides which made them easier to be removed from the matrix during the sliding contact.

The authors of current study have applied EBSM to PTA deposited Stellite 12 hardfacing alloy to investigate if the surface structure and properties could be improved. More specifically the dry sliding wear performance of PTA and EBSM’ed hardfacings have been focused in the scope of this study. To the best of the authors’ knowledge, this approach, i.e. use of EBSM as a post deposition treatment of Stellite 12 hardfacings, has not been reported in open literature.

During the operation of nickel-based alloys as blades and discs in turbines, the sliding activity between metallic surfaces is subjected to structural and compositional changes. In as much as friction and wear are influenced by interacting surfaces, it is necessary to investigate these effects. This study aims to understand better the mechanical and tribological characteristics of Ni-17Cr-10X (X = Mo, W, Ta) ternary alloy systems developed via spark plasma sintering (SPS) technique.

Nickel-based ternary alloys were fabricated via SPS technique at 50 MPa, 1100 °C, 100 °C/min and a dwell time of 10 mins. Scanning electron microscopy, X-Ray diffraction, energy dispersive X-ray spectroscopy, nanoindentation techniques and tribometer were used to assess the microstructure, phase composition, elemental dispersion, mechanical and tribological characteristics of the sintered nickel-based alloys.

The outcome of the investigation showed that the Ni-17Cr10Mo alloy exhibited the highest indentation hardness value of 8045 MPa, elastic modulus value of 386 GPa and wear resistance. At the same time, Ni-17Cr10W possessed the least mechanical and wear properties.

It can be shown that the SPS technique is efficient in the development of nickel-based alloys with good elemental distribution and without defects such as segregation of alloying elements, non-metallic inclusions. This is evident from the scanning electron microscopy micrographs.

This paper aims to present a comparative study of the wear properties of ferrous welded materials like EN8, EN9 and mild steel (MS).

The material is cut into specific dimension after hardfacing and is studied for the wear properties of the material. The wear testing is done on a pin-on-disc apparatus. The microhardness of the material is studied using the Vickers microhardness measuring apparatus.

The wear properties of ferrous welded materials like EN8, EN9 and MS are studied. It is found the MS has the least wear when compared to EN8 and EN9. The microhardness of MS is higher than EN8 and EN9, thus making it more wear-resistant than EN8 and EN9. The coefficient of friction in the dry sliding condition is found to be constant throughout the experiment.

Major restriction is the amount of time required for use-wear analysis and replication experiments that are necessary to produce reliable results. These limitations mean that the analysis of total assemblages with the intention of producing specific results, especially of worked materials, is not feasible.

Generally, the complexity and rigour of the analysis depend primarily on the engineering needs and secondarily on the wear situation. It has been the author’s experience that simple and basic wear analyses, conducted in the proper manner, are often adequate in many engineering situations. Integral and fundamental to the wear analysis approach is the treatment of wear and wear behaviour as a system property. As a consequence, wear analysis is not limited to the evaluation of the effects of materials on wear behaviour. Wear analysis often enables the identification of nonmaterial solutions or nonmaterial elements in a solution to wear problems. For example, changes in or recommendations for contact geometry, roughness, tolerance and so on are often the results of a wear analysis.

The value of the work lies in the utility of the results obtained to researchers and users of the EN8, EN9 and EN24 material for their components.

The purpose of this paper is to apply the upsetting process to cylindrical specimens using flat end dies in which three types of lubricants were used. In many industrial processes, friction and lubrication have major advantages and are key during the metal forming process. Upset forging is a process which increases the diameter of the work-piece by compressing its length.

The materials flow for various materials using different lubricants in upsetting was investigated in this study. AISI 304 austenitic-stainless steel and commercially pure aluminium (Al99.7) were used as the test materials. The upsetting process was applied to the cylindrical specimens using flat end dies. Three types of lubricants, namely, grease, graphite and SAE 40 oil, were used in this study. Experiments were performed using a hydraulic press, which has 5 mm/s ram speed, with a capacity of 150 metric tons. On the other hand, finite element methods (FEMs) have been carried out to analyse the forming performance for displacement prediction in the barrelling process.

The results showed that the measured radius of the curvature of the barrel seemed to confirm the calculation values used before the initiation of the experimental process. It has been observed that the surface roughness had no considerable effect on the barrelling contour changes on the free surfaces, as it showed an increasing deformation ratio for all materials and lubricant types. However, minimum friction at the interface seems to occur with the grease lubricant. The present analyses show that FEMs, which can be used in the rapid prediction of required barrelling process displacements, are more suitable for use in a pressure distribution analysis for the development of the barrelling radius.

It would be interesting to search the material flow for more different materials and lubricants. It could be a good idea if future work could be concentrated on the material flow on upsetting by using different lubricants.

Open-die forging, which is also known as the upsetting process, is one of the simplest forging operations used in bulk deformation processes. This operation can be explained as a solid work-piece which is positioned between two flat dies, and then with the aid of compression, the height of the work-piece is reduced under controlled working parameters during the upsetting process, in which friction and surface roughness are the major parameters playing an important role on the material flow. In a cold upsetting process, one of the undesirable conditions is that barrelling occurs as a consequence of friction between the work-piece and the die surfaces. The existence of this frictional constraint directly affects the plastic deformation of the work-piece, as friction causes barrelling in upsetting processes. However, it has been observed that the use of lubricants reduces the degree of bulging.

This paper will be useful for industrial applications.

The main value of this paper is to contribute and fulfil in detail the material flow of various materials using different lubricants that are being studied so far in the literature.

This paper aims to reveal the effects of the copper third body on different copper matrix friction materials with a novel experimental way called “exogenous powder.”

An accurate adding device of exogenous copper powder was designed to control the flow rate. The tribological properties with and without exogenous copper powder were investigated by a pin-on-disc tribometer during dry sliding.

Experimental results indicate that the Cu addition tends to increase the friction coefficient. For pure Cu material, the exogenous copper third body exhibits poor fluidity on the friction surface, causing serious adhesive wear on the friction interface. For the Cu 90% + 10% Gr material, the plasticity of exogenous copper powder may intensify the deformation of the third body of the surface, presenting layered accumulation distribution. For the pure Cu and Cu 95% + 5% SiO₂ material, the Cu addition makes the composition and density of the third body uneven in the direction of depth.

The role of the copper component on different materials is revealed from a new perspective, and the relationship between the third body structure and the friction properties is explored.

The purpose of this paper is to study the friction and wear properties of CrNiMo steel pin against brass disk in different oxygen fractions. CrNiMo steel is currently widely used in industry and military fields for its excellent performance in some severe environments. The atmosphere and temperature are key factors affecting the wear behaviors of CrNiMo steel. The study aims to make better use of CrNiMo steel in different atmospheres.

Friction and wear experiments were conducted using a pin‐on‐disk tribometer equipped in an atmosphere controllable chamber. The chamber allows switch between vacuum and gas mixtures of N2 and O2. The oxygen content was managed by magnetic coupling flow meter. The sliding speed of 1, 2, 3, 4 m/s and the applied sliding contact load of 5, 6.5, 8, 9.5 N were used in friction test. In order to obtain information on the wear mechanisms, the worn surface of the pin was examined by scanning electron microscopy and energy dispersive X‐ray spectroscopy.

A close dependence is clearly shown of the friction and wear on the content of oxygen gas in elevated temperature. Increasing the content of oxygen in the atmosphere under higher normal load condition is beneficial to friction reduction of the steel/brass pair. Different wear mechanisms were found with a transition from the adhesive wear in nitrogen, to a mixed adhesion and oxidation wear when increasing the content of the oxygen in the atmosphere.

This paper provides a reference for the similar steel used in severe environments.

Aerospace field is demanding a material with superior strength and high resistance against wear, tear and corrosion. The current study aimed to develop a new material with high performance to be applicable in aerospace field

A metal matrix composite AA8090-WC-ZrC was fabricated using stir casting method and its tribological behavior was investigated. Totally, five composites viz. AA/Z, AA/W, AA/WZ (1:3), AA/WZ (1:1) & AA/WZ (3:1) were prepared. Micro hardness, tensile and wear study were performed on the fabricated composites and the results were compared with AA8090 alloy

Vickers hardness test resulted that the AA/W composite showed the higher hardness value of 160 HB compared to other materials due to the reinforcing effect of WC particles with high hardness. Tensile test reported that the AA/W composite displayed the maximum tensile strength of 502 MPa owing to the creation of more dislocation density. Further, wear study showed that the AA/W composite exhibited the least wear rate of 0.0011 mm3/m because of the more resisting force offered by the WC particles. Furthermore, the AA/W composite showed the slightest mass loss of 0.0028 g and lower COF value of 0.31 due to the hinder effect of WC particle to the movement of atoms in AA8090 alloy

This work is original in the field of aerospace engineering and materials science which deals with the fabrication of AA8090 alloy with the reinforcement particles such as tungsten carbide and zirconium carbide. The impact of the combination of hybrid particles and their volume fractions on the tribological properties has been investigated in this work. This work would provide new scientific information to society.

Ti6Al4V is a commonly used titanium alloy with several applications in aerospace industry due to its excellent strength to weight ratio. But due to low thermal conductivity, it is categorized as “difficult to machine.” Though machinability can be improved with cutting fluids, it is not preferred due to associated problems. This study aims at eliminating the use of cutting fluid and finding an alternate solution to dry machining of Ti6Al4V. AlTiN coated tools provide good heat and oxidation resistance but have low lubricity. In the present work, graphene, which is known for lubricating properties, is added to the tools using five different methods (tool condition) to form graphene self-lubricated cutting tools.

Graphene-based self-lubricating tools are prepared by using five methods: dip coating (10 dips and 30 dips); drop casting; and filling of micro/macroholes. Performance of these tools is evaluated in terms of cutting forces, surface roughness and tool wear by machining Ti6Al4V and comparing with conventional coated cutting tool.

Self-lubricating tool with micro holes filled with graphene outperformed other tools and showed maximum decrease of 33.42% in resultant cutting forces, 35% in surface roughness (Ra) and 30% in flank wear compared to conventional cutting tool.

Analysis of variance for all forces show that tool condition and machining time have significant influence on all components of cutting forces and resultant cutting forces.

This study aims to investigate and present the tribological behaviour of recursively friction stir processed 7075 aluminium alloy.

In this work, aluminium 7075 alloy is friction stir processed recursively by varying the tool rotational speed, traverse speed and the number of passes. Wear pins for testing were extracted from the processed zone and the surfaces were prepared. Wear tests were conducted as per the standard on a pin-on-disc wear testing machine at constant testing conditions and the corresponding tribological properties were analysed. The worn surface and the debris were analysed using a field-emission scanning electron microscope with energy dispersive spectroscopy analysis and elemental mapping to identify the mode of wear mechanism.

The experimental results indicate that the specimen fabricated at 1,150 rpm of tool rotation speed and 60 mm/min of traverse speed with 4 passes had the highest wear resistance and the minimum friction coefficient.

This paper details the effect of recursive friction stir processing on the surface of AA 7075 to improve the tribological properties.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0070/