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The purpose of this paper is to characterize carbide coatings obtained by thermo reactive diffusion (TRD) method on AISI 52100 and 440C bearing steels, which are extensively used in industry, and to study wear behaviour of coated steels at elevated temperatures.

For coatings of vanadium and titanium carbides, TRD treatment is performed on AISI 52100 and 440C steels using pack method at 950°C for 3 h. Carbide coatings are characterized using X‐ray diffraction (XRD). The Daimler‐Benz Rockwell‐C adhesion test and micro‐Knoop indenter is used to assess the adhesion and hardness of the carbide layers, respectively. Ball‐on‐disc arrangement is used for determination of tribological properties of carbide‐coated steels. Friction and wear tests are carried out against Si₃N₄ ball at elevated temperatures up to 600°C under 5 N load, for sliding speed of 0.3 m/s.

The presence of carbides formed on AISI 52100 (Ti₆C_3.75 and VC_0.88 phases) and on AISI 440C (Ti₆C_3.75, VC_0.88 and minor Cr₂₃C₆ and Cr₇C₃ phases) is confirmed by XRD analysis. Hardness values of titanium and vanadium carbides on the 52100 and 440C steels are about 2,175‐2,464 and 2,128‐2,433 HK_0.05, respectively. Friction experiments show that this type of coating is more effective than the substrates in regards to achieving lower friction up to 300°C. Above this temperature, the effect of substrate is more dominant on the friction coefficient. Scanning electron microscopy and energy‐dispersive X‐ray analysis results show the presence of the compact oxide layers at elevated temperatures as a result of increased sintering and oxidation of the wear debris.

This paper deals with only characterization of vanadium and titanium carbide coatings and high temperature wear properties of the coated steels.

Carbide coatings obtained by TRD method are satisfactory in terms of high temperature tribological applications in comparison with those produced vapor deposition processes, which are expensive and complicated equipment.

There is no literature about high temperature wear and friction behaviour of TRD carbide‐coated 52100 and 440C steels. In this study, there are new results on high temperature wear of TRD carbide‐coated steels.

Aluminium metal matrix composites are used in automotive and aerospace industries because of their high performance and weight reduction benefits. The current investigation aims to focus on the development of the stir cast aluminium-boron carbide composites with enhanced mechanical and tribological properties.

The aluminium-boron carbide composites are produced by stir casting process. Aluminium alloy A356 is chosen as the matrix material and three sets of composites are produced with different weight fractions of boron carbide particles. Higher particle size (63 µm) of boron carbide is chosen as the reinforcement material. Aluminium-boron carbide composites are tested for mechanical and tribological properties. The effect of process parameters like load, speed and percentage of reinforcement on the wear rate are studied using the pin-on-disc method. The interaction of the process parameters with the wear rate is analysed by DesignExpert software using RSM methodology and desirability analysis. The coded levels for parameters for independent variables used in the experimental design are arranged according to the central composite design. The worn surface of the pin is examined using a scanning electron microscope. The phases and reaction products of the composites are identified by X-ray diffraction (XRD) analysis.

Aluminium-boron carbide composites reveal better mechanical properties compared to monolithic aluminium alloys. Mechanical properties improved with the addition of strontium-based master alloy Al10Sr. The ultimate tensile strength, hardness and compressive strength increase with an increase in the reinforcement content. The wettability of the boron carbide particles in the matrix improved with the addition of potassium flurotitanate to the melt. Uniform dispersion of particles into the alloy during melting is facilitated by the addition of magnesium. Wear resistance is optimal at 8 per cent of boron carbide with a load 20 N and sliding speed of 348 RPM. The wear rate is optimized by the numerical optimization method using desirability analysis. The amount of wear is less in Al-B₄C composites when compared to unreinforced aluminium alloy. The wear rate increases with an increase in load and decreases with the sliding speed. The wear resistance increases with an increase in the weight fraction of the boron carbide particles.

The produced Al-B₄C composites can retain properties at high temperature. It is used in nuclear and automotive products owing its high specific strength and stiffness. The main applications are neutron absorbers, armour plates, high-performance bicycles, brake pads, sand blasting nozzles and pump seals.

Al/B₄C composites have good potential in the development of wear-resistant products.

The purpose of this study is to analyse and optimize the wear parameters of magnesium metal-metal composite. Materials with lesser weight attract both the researcher and industrialists, as it exhibits the performance improvement in the automotive and aerospace industries. The enrichment of mechanical and tribological properties of the existing magnesium focussed the development of new metal–metal composite.

Metal–metal composite with magnesium matrix was synthesized through the disintegrated melt deposition technique with the addition of titanium, aluminium and boron carbide particles. The wear performance of the composite was experimented with the dry sliding wear test by considering load, sliding velocity and sliding distance.

The wear rate of the composite is analysed statistically, and the significance of wear parameters on the wear performance of metal–metal composite is observed. The worn pin surface and the wear debris collected during the wear experiments were exposed to the microscopy analysis to seize the dominating wear mechanisms.

The wear performance of the developed magnesium composite was analysed and discussed in detail with the support of scientific evidence, i.e. worn surface and debris analysis express the wear mechanisms.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0326/

This paper consolidates and presents the results of a work conducted to fabricate micro-channels on titanium grade-2 material by ultrasonic machining process (USM). In this research, the effects of important USM parameters, namely, kind of abrasives and its size, concentration of slurry, USM power rating and feed rate, have been probed on micro-channels quality for average surface roughness and process throughput in the form of material removal rate.

Multiple micro-channels on commercially pure titanium (i.e. Ti grade-2) have been fabricated in a single pass by employing micro-tool based USM process. Taguchi-based L18 (mixed level) OA has been selected for experimental design. Analysis of variance (ANOVA) study and regression modeling have also been done. Non-Dominated Sorting Genetic Algorithm (NSGA-II) has been used for process optimization to get optimum values of material removal rate (MRR) and surface roughness (SR).

The influence of important USM variables on SR and MRR have been investigated, and NSGA-II-based multi-response optimization has been done. The best surface roughness values obtained via NSGA-II solution for SiC and B₄C are 0.354 µm and 1.303 µm, respectively. Scanned electron microscopic investigation proves the fabrication of micro-channels with smooth surfaces, and minimum burrs and other defects. The material removed from the surface was due to ductile fractures.

Miniaturization is a modern trend these days to solve many precision, scientific and industrial problems. To manufacture precise micro-products, shapes and features, advanced and micro-machining processes can play a very prominent role. Micro-channels are typical micro-features required in micro-fluidic applications like micro heat exchangers and micro-pumps. Exhaustive review of existing research work indicated that precision micromachining of various materials can be effectively performed using USM, though not much work has been undertaken to explore the feasibility of multiple micro-channels in a single run using USM. The current work fulfills the gap, where multiple micro-channels on commercially pure titanium (i.e. Ti grade-2) have been fabricated in a single pass by employing micro-tool-based USM process.

The reduction of wear by the use of sprayed surface coatings holds considerable potential at a time when Industry is becoming more conscious of the need to reduce its operating costs. Control of wear is unlikely to become a true science due to the arbitrary nature of the conditions that produce the effect and although no truly economic solution exists for completely preventing surface degradation, it can be minimized to acceptable limits. It is the purpose of this article to present an approach to the use of sprayed surface coatings in tribological situations. Common wear types are briefly described and the philosophy behind the protective surface layer in relation to surface geometry is outlined. The performance of sprayed coatings in adhesive and abrasive wear situations is evaluated and discussed. In addition, the use of sprayed deposits for lubricated bearing surfaces is considered as well as the application of low friction coatings by the spray method.

IN only a few years Garryson Ltd of Ibstock in Leicestershire has become the leading U.K. specialist in solid carbide round tools. Traditionally British users of these tools have had to turn to American, German or Swiss suppliers because no satisfactory home‐based manufacturer existed, but in 1985 Garryson decided to fill this gap in the market.

Probleme des Plastizitätsthcorie (Problems of the Theory of Plasticity). By William Prager [Birkhäuser Verlag, Basel and Stuggart, Sf 12.50].

Metal matrix composites (MMC) has been a section which gives an overview of composite materials and owing to those exceptional physical and mechanical properties, particulate-reinforced aluminum MMCs have gained increasing interest in particular engineering applications. Owing to the toughness and abrasive quality of reinforcement components such as silicon carbide (SiC) and titanium carbide (TiC), such materials are categorized as difficult materials for machining. The work aims to develop the model for evaluating the machinability of the materials via the response surface technique by machining three distinct types of hybrid MMCs.

The combined effects of three machining parameters, namely “cutting speed” (s), “feed rate” (f) and “depth of cut” (d), together with three separate composite materials, were evaluated with the help of three performance characteristics, i.e. material removal rate (MRR), cutting force (CF) and surface roughness (SR). Response surface methodology and analysis of variance (ANOVA) both were initially used for analyzing the machining parameters results.

The contours were developed to observe the combined process parameters along with their correlations. The process variables were concurrently configured using grey relational analysis (GRA) and the composite desirability methodology. Both the GRA and composite desirability approach obtained similar results.

The results obtained in the present paper will be helpful for decision-makers in manufacturing industries, who work on metal cutting area especially composites, to select the suitable solution by implementing the Grey Taguchi and modeling techniques.

The originality of this research is to identify the suitability of process parameters combination based on the obtained research results. The optimization of machining parameters in turning of hybrid metal matrix composites is carried out with two different methods such as Grey Taguchi and composite desirability approach.

Machining operations on multilayer circuit boards play the two major roles of establishing the finished geometry of the board and leading to the interconnection of the various conductor layers and it is likely that for some considerable time carbide cutting tools will continue to be used in the machining process. Fundamental and detailed considerations of the parameters influencing machining are presented prior to analysing the two predominant areas of use. Mention is made of some advanced machining techniques, involving mechanical, chemical and laser methods.

Tribological problems, in common with most other technological problems, are normally solved by one of two methods—1. By the application of existing knowledge. 2. By a research and development programme. The first method, on grounds of speed and economy, is usually the first to be tried and requires the means of characterizing the friction, wear, or lubrication problem, a broad knowledge of the possible alternative solutions and the necessary experience to identify the most cost effective solution. Where no technically satisfactory solution exists or where the solution is economically unattractive, a more basic approach is necessary. Although it can be said that a change of design can have the greatest influence on tribological problems in many instances constraints on change will only permit materials or lubricant substitution or possibly the application of a surface coating. In these instances the tribological problem becomes one of materials development. Examples of the solution of tribological problems by both methods are presented in this paper. They are taken from work recently carried out or presently in progress at the Fulmer Research Institute.