Design of experiment analysis of elevated temperature wear of Mg-WC nano-composites

Current study explores the effect of selected process parameters i.e. wt.% of reinforcement (A), elevated temperature (B) and load (C) on wear characteristics of Mg-WC nanocomposites using Taguchi robust design concept. Ultrasonic treated stir casting is employed to synthesize nanocomposites. Three levels for every factor are taken into consideration and accordingly L27 orthogonal array (OA) is used for minimization of wear rate. Main effect plot is generated to investigate the important parameters and optimality is also predicted from the main effect plot. Optimal condition for minimum wear rate is 2wt.% of WC, 100°C temperature and 20N load (A3B1C1). Interaction plots are generated to scrutinize the interaction outcome between selected parameters. ANOVA study is executed to evaluate significant parameters and their effective handout on output. Current investigation reveals, Wt.% of WC is the most significant factor while temperature and load are moderately significant. Among the interacting parameters, interaction between wt.% of WC & temperature (A×B) has moderate significance. Wt.% of WC (A) has 43.135% contribution while temperature (B), load (C) and interaction between wt.% of WC & temperature (A×B) have 26.623%, 19.037% and 5.639% contribution respectively. Residual plots for wear rate are discussed and confirmation test finally helps to validate present experimental model. S/N ratio is improved by 4.411 dB (48.60%) than the initial condition.

Investigations on Microstructure, Mechanical, Thermal, and Tribological Behavior of Cu-MWCNT Composites Processed by Powder Metallurgy

Copper (Cu) metal matrix composite (MMC) was developed with multiwall carbon nanotubes (MWCNT) as reinforcement by using powder metallurgy (PM) technique. The composition of the composites is Cu, Cu-4 wt% MWCNT, Cu-8 wt% MWCNT, and Cu-12 wt% MWCNT. The Cu and MWCNTs were blended for 6 hours in a ball mill and compacted at a 6 ton pressure to form green compacts using a 10 ton hydraulic press. Using a tubular furnace, the heat was applied at 900°C for 1.5 hours to impart strength and integrity to the green compacts. Milled composite blends were studied to analyze its characterization through SEM and EDAX analysis. Characterization studies such as SEM and EDAX confirm the presence and even dispersion of Cu and MWCNT constituents. The relative density, hardness, and ultimate compressive strength have been studied, and a remarkable improvement in properties has been obtained by the inclusion of MWCNTs. The composites reinforced by 8 and 12 wt% MWCNT were recorded with low thermal conductivity than the Cu composite reinforced by 4 wt% MWCNT. A wear study was analyzed using Taguchi technique for determining the effect caused by the wear test parameters and MWCNT content on wear rate. The optimized parameter that contributes minimum wear rate was identified as 12 wt% MWCNT content, 10 N applied load, 2 m/s sliding velocity, and 500 m sliding distance. Based on the obtained results, it could be understood that the produced composites can be utilized for various applications like relay contact springs and switchgear, rotor bars, and bus bars.

Tribological Investigation of Self-Lubricated Al-SiC-Kaoline Hybrid Composite Under Dry, Oil and Nanofluids Lubricating Conditions Fabricated Through Spark Plasma Sintering Technique.

In this present study Al-10% SiC- X % Kaoline (X= 0, 2, 4, 6, 8) HMMC synthesized by spark plasma sintering technique. The fabricated HMMC samples corresponding to maximum compression strength was subjected to tribological investigation under dry, oil and nanofluids lubricating conditions. Nanofluid lubricants were developed by incorporating SiC nanoparticles with weight percentages of 1 wt%, 1.5 wt% and 2 wt% into the soluble oil. The thermal conductivity was found to be increased with increasing the wt % of SiC nanoparticles and the maximum thermal conductivity of 0.771 W/m.K was obtained for the nanofluids with 2 wt% SiC nanofluids. Sliding wear test was conducted on the pin-on-disc tribometer at 40 N load and sliding speed of 1500 r.p.m for a sliding of 180 s. Results reveal that there was a significant effect of the lubricating conditions (dry, oil and nanofluids) on the wear and C.O.F of the HMMC pin surface. The minimum wear of 119 microns and minimum C.O.F of 0.11 was obtained for nanofluid with 2 wt% SiC nanofluid lubricating conditions. SEM analysis of worn surface under dry and soluble oil lubricating conditions reveal the presence of microcracks and delaminations wear. However, worn surface with smooth grooves and absence of microcracks was identified under nanofluid lubricating conditions.

Effect of Silica-Based Wastes on Wear Rate and Hardness Properties of Epoxy Composites as a Construction Material

In this study, polymer composites were manufactured with epoxy-based resin and wastes as a mineral additive. The wastes including a high content of silica (Silica fume, glass and fly ash) powder were used as fillers for an epoxy adhesive to improve its wear resistance properties. They were supplemented to mixes in various ratios via substituting the resin from 0 to 20% by weight. Tests of wear rate and hardness were conducted upon all-polymer composites at all fillers ratios. Results indicated that the epoxy hardness increased with increasing the filler addition. Consequently, the addition of wastes that include silica raised the wear resistance of polymer composites; nevertheless, it caused the composites harder materials. The wear rate decreased with increasing the silica fume, glass, and fly ash addition. In the case of fly ash addition, the minimum wear rate was at 15%, and after this percentage, the wear rate increased. However, in the case of glass addition, the minimum wear rate was at 10%, and after this percentage, the wear rate increased.

Tribological and Thermo-Mechanical Properties of TiO2 Nanodot-Decorated Ti3C2/Epoxy Nanocomposites

The micromorphology of fillers plays an important role in tribological and mechanical properties of polymer matrices. In this work, a TiO2-decorated Ti2C3 (TiO2/Ti3C2) composite particle with unique micro-nano morphology was engineered to improve the tribological and thermo-mechanical properties of epoxy resin. The TiO2/Ti3C2 were synthesized by hydrothermal growth of TiO2 nanodots onto the surface of accordion-like Ti3C2 microparticles, and three different decoration degrees (low, medium, high density) of TiO2/Ti3C2 were prepared by regulating the concentration of TiO2 precursor solution. Tribological test results indicated that the incorporation of TiO2/Ti3C2 can effectively improve the wear rate of epoxy resin. Among them, the medium density TiO2/Ti3C2/epoxy nanocomposites gained a minimum wear rate. This may be ascribed by the moderate TiO2 nanodot protuberances on the Ti3C2 surface induced a strong mechanical interlock effect between medium-density TiO2/Ti3C2 and the epoxy matrix, which can bear a higher normal shear stress during sliding friction. The morphologies of worn surfaces and wear debris revealed that the wear form was gradually transformed from fatigue wear in neat epoxy to abrasive wear in TiO2/Ti3C2/epoxy nanocomposites. Moreover, the results of thermo-mechanical property indicated that incorporation of TiO2/Ti3C2 also effectively improved the storage modulus and glass transition temperature of epoxy resin.

Lubrication performance of magnetorheological fluid in shear mode magnetorheological clutch with and without groove

In this work, the lubrication performance of magnetorheological fluid-filled parallel discs of shear mode magnetorheological clutch is investigated. A magnetorheological fluid contains magnetic particles responsible for the yield strength and hence torque transmission capability in the magnetorheological clutch. The wear damages of magnetic particles of a magnetorheological fluid and magnetorheological clutch discs are examined by scanning electron microscopy and optical microscopy. Energy-dispersive X-ray spectroscopy is used to investigate the variation in chemical composition before and after the experimental test. A test rig is developed to test the torque transmission for a fabricated magnetorheological clutch with a grooved and non-grooved disc. The grooves' impact on both magnetorheological clutch discs' wear and magnetorheological fluid is investigated. It has been observed that the minimum wear damage occurs in the magnetic particles and the disc surface for the circular grooved magnetorheological clutch disc surface than the non-grooved disc surface. An effect of surface texture on the temperature distribution of the magnetorheological clutch is studied through simulation. Simulation results show that the groove's presence on the disc surface can improve the magnetorheological clutch's heat transfer. Hence, the grooved texture improves the lubrication performance and durability of both magnetorheological fluid and magnetorheological clutch.

Wear of the PG-CP4 powder coating applied to HVG steel and subjected to laser treatment

The article considers the influence of the radiation power W, the longitudinal feed Spr of the laser beam and the distance L from the protective glass of the laser focusing head to the workpiece on the PG-CP4 powder coating absolute wear which was applied to HVG steel by plasma and subjected to laser treatment. A multi-factor model is established that relates the absolute wear of PG-CP4 coating to the input process factors and allows you to assign a laser treatment mode to provide the minimum wear of the processed surface layer. The greatest influence on coating absolute wear is provided by the longitudinal feed of laser beam, with which the wear increases. Compared to Spr, the influence of factor W on the coating absolute wear is 24% less, and the factor L influence is 4.4 times less. The minimum absolute wear of the coating occurs at W = 5 kW, Spr = 40 mm/s, L = 85 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern technological laser systems.

ХАРАКТЕР ИЗМЕНЕНИЯ ГЛУБИНЫ ЛУЧЕВИДНОГО ИЗНОСА ПРИ РАЗЛИЧНЫХ ВАРИАНТАХ АРМИРОВАНИЯ ДОЛОТООБРАЗНОЙ ОБЛАСТИ ЛЕМЕХОВ ПРИ ВСПАШКЕ ТЯЖЕЛЫХ ПОЧВ

During the operation of the plow body, a number of defects are formed on the bit-shaped part of the plowshare, one of which is xiphoid wear. Renewing the life of a given part is often reduced to eliminating such wear in various ways that are not always rational. This occurs due to insufficient knowledge of the dynamics of xiphoid wear, especially little information about plowing heavy soils. (Research purpose) The research purpose is in identifying the nature of changes in the depth of xiphoid wear in various options for reinforcing the chisel-shaped area of ploughshares when plowing heavy soils. (Materials and methods) Authors conducted research using all-metal ploughshares of domestic production in the state of delivery and reinforced according to the schemes of the location of reinforcing rollers. The reinforcement rollers were formed using E42A-UONII-13/45 electrodes designed for welding carbon steels. The thickness in the area of the ploughshare wear was determined using a calibration plate, prisms, and an indicator micrometer with an accuracy of 0.01 millimeters. To ensure the same conditions of the experiment, it was carried out in fields where the soils had the same granulometric composition, which was loam with a physical clay content of 33-38 percent. (Results and discussion) The article reveals dynamics of the development of the xiphoid wear depth depending on the operating time and technological methods of strengthening reinforcement of the chisel-shaped part of the ploughshare. The article describes the technology of strengthening reinforcement that provides the minimum wear depth with the same operating time. (Conclusions) The article presents a method for determining the depth of xiphoid wear. The proposed technology of reinforcement of ploughshares with rollers perpendicular to the field edge, with surfacing of the buried part to a length of 100 millimeters and reinforcement of the heel will increase the resource of the part by 1.3 times.

Experimental Investigation on Post Processed Nicr Thermal Barrier Coating And Its Sliding Wear Behaviour

The NiCr metal is deposited on martensitic stainless steel using atmospheric plasma spray method. To enrich the metallurgical properties of the NiCr metallic coating, a standard heat treatment process is adopted. From the investigation it has been clarified that the voids and porosity developed during the thermal spray has been controlled through the heat treatment. Electron image analysis reflects that the coating has reduced porosity with strong and dense bonding strength. With reference to the surface hardness, the post processed coating yields maximum of 140 Hv compared to as coated (129 Hv) and base metal (115 Hv). Subsequently the sliding wear behaviour of post processed NiCr Coating has a minimum wear 25µm for 5N and 57µm for 15N applied load respectively. Due to the high metallurgical bonding, the coating has sustained the heavy loads and the wear formation is controlled. However, the base metal has adhesive wear mechanism due to high frictional force on sliding friction. Since, it is recommended that the post processed thermal barrier coatings can possess good metallurgical bonding and withstand heavy load causing minimum wear.