Study on Mechanical and Wear Behaviour of AA7075/TaC/Si3N4/Ti Hybrid Metal Matrix Composites

This research article focuses on the development of AA7075 alloy reinforced with different wt% of Tantalum Carbide (TaC), Silicon Nitride (Si3N4) and Titanium (Ti) particulates using stir casting. Mechanical characteristics like tensile, compression and microhardness of the developed composites were analysed. High temperature tribological properties of the hybrid MMCs were studied for various input control factors like sliding speed, load and temperature. Design analysis has been executed by Taguchi orthogonal array and ANOVA (Analysis of Variance). The incorporated reinforcements exhibited improved wear resistance at ambient temperature along with elevated temperatures. Monolithic dissemination of reinforcement’s in the prepared composites magnifies the mechanical and tribological characteristics for composites compared to matrix material. From the optimization technique, it was witnessed that Wear Rate and Frictional Coefficient are afflicted by temperature go after load & sliding speed. The optimal amalgamation of control parameters of distinct tribo-responses has been detected.

Mechanical and tribological behaviour of PA6 and short aramid fiber composites

This paper presents the results of mechanical and tribological characteristics for two composites: PA6 as matrix and 5% aramid whiskers as additive material and PA6 + 10% aramid whiskers, comparing them to those made of PA6 (polyamide 6). To improve the mechanical and thermal properties of polyamide (PA6), the composites were prepared via the Brabender lab mixer and mould forming under given pressure and temperature conditions. Test specimens made of pure PA6 and PA6 mixed with 5 wt.% and 10 wt.% aramid whiskers were subjected to mechanical tests (three-point bending and impact), thermo–mechanical test (HDT - heat deflection temperature), tribological test (block-on-ring) and analyzed from morpho-structural point of view. Compared to the PA6 samples, the mass concentrations of aramid whiskers improved the HDT deflection temperature values. In the case of samples with 5% aramid whiskers, the absorbed energy increased by 13% and for those with 10% aramid whiskers they increased by 30%. Aramid whiskers-doped materials performed much better on severe tribological testing as compared to PA6 samples. Increasing the deflection temperature, also improved their resistance from a tribological point of view.

Mechanical and tribological characteristics of laser-deposited nickel-containing powders on chromium steels

This paper presents the results of a study of various processing modes during the laser surfacing process. Various grades of steel were used as samples, and the resulting coatings were based on two grades of powders. The microhardness values were obtained both for the main steel material and for the coatings obtained on the samples. The values of the friction coefficients of the coatings are obtained, on the basis of which the graphs of standard deviations are constructed. The results are summarized using graphs and figures.

Investigation of physical, mechanical and tribological properties of corrosion-resistant steel with laser surface surfacing of WC100Co4Cr

The article investigated the effect of laser surfacing of WC100Co4Cr powder on the surface of corrosion-resistant steel on hardness, tensile strength and yield strength, coefficient of friction and the amount of wear of products made of alloy structural cryogenic steel. The SVAROG-1-5DR laser complex (Russia) was used for laser processing. Various modes of surface laser surfacing were set. For this purpose, the power of the laser radiation, the speed of movement of the laser beam relative to the treated surface and the focal length were varied. The measurement of physical, mechanical and tribological characteristics was carried out using the equipment of the company “CSM Instruments” (Switzerland). The structure of the alloy was studied by metallography and X-ray diffractometry. The results showed a significant increase in hardness, tensile strength and yield strength and a decrease in the coefficient of friction.

The performance evaluation of heavy loaded tribosystems with vacuum ion-plasma PVD and DLC coatings

The results of studies of the physical, mechanical and tribological characteristics of PVD and DLC coatings are presented. The complex of basic mechanical properties (hardness H and elastic modulus E), as well as derivatives of mechanical characteristics H/E and Н3/Е2 , were investigated by the method of continuous indentation at various loads. The friction coefficient, the wear rate of the sample and the counterbody were determined as tribological indicators. The applied purpose of the work was to determine the friction unit for applying the developed coatings, materials and modes of applying PVD and DLC coatings. To solve this problem, a test bench was designed and built that simulates the operation of the selected friction unit. As a result of the research carried out, the results of laboratory and bench tests were compared. The performance of the coatings was determined by the volume of the tooth wear of the sleeve and the tip with the help of the method of micrometric measurements. As a result of the study of the surface morphology, the volumes of wear of rubbing conjugations and the intensity of their wear were determined. It has been established that the results of bench tests confirm laboratory studies and suggest that such an installation can be used for researching other heavily loaded spline conjugations.

Nanomechanical, Tribological, and Scratch Properties of Electroless Ni-B-W Alloy and Ni-B-W-SiC Composite Coatings

Electroless deposition process can develop composite coatings superior in mechanical and tribological characteristics. The deposited alloy matrix with the reinforcement of a hard ceramic phase can produce a stronger composite coating, favorable for industrial applications. Fabrication process of Ni-B-W-SiC electroless composite coating on steel substrate by reinforcing silicon carbide (SiC) in ternary Ni-B-W matrix is presented in this report. Characteristics of the developed composite coating are studied in reference to electroless ternary Ni-B-W alloy coating. These ternary alloy and composite coatings are also subjected to heat treatment (450oC, 1 hr) to observe the changes. All coated samples are characterized with FESEM, XRD, ICP-AES, and HRTEM analyses to draw conclusions in comparative studies concerning morphological features, compositions, and phase structures. Cross-sectional and Raman spectroscopic examinations are performed to authenticate the presence of SiC phases in alloy matrix. To get a further insight on the nature, various nanomechanical and tribological properties of these coatings are evaluated and subsequently co-related. Coatings developed with silicon carbide particles present in matrices show remarkable improvements in nano-hardness (H), reduced modulus (Er), yield strength, and fraction of plastic work done. Heat treatment imparts propitious effects on these mechanical properties due to the formation of harder nickel boride (Ni3B, and Ni2B) phases. Heat-treated Ni-B-W-SiC composite subjected to tribological and micro-scratch testing reveals a significant improvement in sliding wear and scratch resistance as compared to those in other coatings.

Mechanical and Tribological Characteristics of Aluminium 2618 Matrix Composite Reinforced with Boron Carbide

Aluminium-based alloys are mainly used for bearing and automotive applications, resulting in more wear and tear of the material. Boron Carbide (B4C), hard ceramic materials used as reinforcement in Al2618 matrix material, was fabricated using the stir casting method. The presence and distribution of the B4C particles were confirmed by X-ray diffractometer (XRD) and Scanning Electron Microscopy (SEM). Taguchi’s design of experimental approach was employed to study the wear characteristics using the L27 orthogonal array. Optimization of parameters like applied load (20, 30, and 40 N), sliding distance (400, 600, and 800 m), and sliding speed (1.25, 2.51, and 3.76 m/s) were done using Signal-to-Noise ratio analysis and Analysis of Variance (ANOVA). Results revealed that speed (46.77%) had more influence on wear behavior, followed by sliding distance (34.74%) and load (9.81%). SEM images of the worn-out composite specimens exhibited an adhesive type of wear mechanism with deep grooves from hard B4C particles.

Mechanical and Tribological Characterization of a Bioactive Composite Resin

Despite developments and advances in dental materials which allow for greater restorative performance, there are still challenges and questions regarding the formulation of new compositions and chemical reactions of materials used in restorative dentistry. The aim of this study was to assess and compare the mechanical and tribological characteristics of a bioactive resin, a composite resin, and a glass ionomer. Twenty specimens of each material were divided into two groups: one control group (n = 10), not subjected to thermocycling, and one test group (n = 10) submitted to thermocycling. The Vickers microhardness test was carried out and surface roughness was evaluated. The tribological sliding indentation test was chosen. The bioactive resin had the lowest hardness, followed by the composite resin, and the glass ionomer. The bioactive resin also showed greater resistance to fracture. For the tribological test, the wear rate was lower for the bioactive resin, followed by the composite resin, and the glass ionomer. The bioactive resin presented a smooth surface without visible cracks, while the other materials presented a brittle peeling of great portions of material. Thus, the bioactive resin performs better in relation to fracture toughness, wear rate and impact absorption than the composite resin and much better than the glass ionomer.