Applied Mechanics and Materials Vols. 592-594

Abstract: Among several nanocoatings, Ti and B₄C hard coating shows excellent wear performance in cutting tool operation. This hard nanocoating Implemented on GCI substrate using EB-PVD coating is to make them suitable for engine components and to act as a protective coating against surface wear and reduce the wear of the components. The wear test was conducted using Pin-on-disc equipment at the room temperature and surface roughness was measured using surface roughness tester.The wear parameters such as sliding speed and sliding distance were kept constant and the load is varied. Coating hardness was measured using Brinell hardness tester.The investigation shows that Ti, B₄C coatings have significant effect on GCI sleeve. Also, the result shows that the coating of Ti, B₄C improved the wear resistance of the grey cast iron.

Abstract: The explorative attempt to harness new materials that could be utilized for manufacturing products with sophisticated geometry for aerospace and automotive applications necessitate the exploitation of Al-Si-Mg alloy family. Al-14Si alloys which posses 1% Mg exhibits a microstructure that contains primary Si particles, eutectic Si and Mg₂Si in α-Al matrix. With a view to improve the mechanical properties of this alloy, Sr modification was carried out by adding 0.04% Sr to the molten metal. The Mg₂Si phase has high melting temperature, low density, high hardness, low co-efficient of thermal expansion and high elastic modulus. The best results in the microstructure were obtained through a combination of Sr addition and T6 heat treatment which enhances the mechanical properties and wear resistance of the alloy.

Abstract: The present study investigates the effect of different coating parameters along with heat treatment on the tribological properties of Ni–P–Al₂O₃ composite coating, deposited on mild steel substrate. The coefficient of friction and wear depth (μm) are optimized for increasing performance of the composite coating using Grey Taguchi analysis by considering three parameters, namely, concentration of nickel source, concentration of reducing agent, and concentration of alumina particles. Tribological properties of the composite coating after heat treatment at 400°C are evaluated by using plate-on-roller type of tribotester. It is observed that concentration of reducing agent and alumina particles have the significant influence on corrosion resistance at 400°C. Effects of operating parameters on microstructure, and crystallization are investigated using SEM and EDX techniques.

Abstract: Effects of graphite content, and sliding speed on the tribological characteristics of copper-graphite composites under dry sliding condition were evaluated using a pin-on-disc tribometer. The worn surfaces of the composites were analyzed through Scanning Electron Microscopy (SEM). The experimental results revealed the improvement in wear resistance with increasing graphite content. The friction coefficient is also gradually decreasing upto 25 vol% graphite. Sliding speed has an effect on copper (5-15 vol%) graphite composites where as sliding speed has no effect in copper-(20-30 vol%) graphite composites. This difference is attributed to availability of self-lubricating graphite layer at the contact zone.

Abstract: This paper reports on prediction and comparison of tribological behavior of Al2024-TiB₂ in-situ metal matrix composites using Group Method Data Handling Technique (GMDH) and Artificial Neural Network (ANN). Experiments were carried out using Pin-On-Disc type testing machine as per ASTM standards by varying the loads and sliding velocities. Two responses namely coefficient of friction and wear rates have been considered for each experiment. It was found that, ANN is the most reliable and accurate technique for prediction compared to GMDH.

Abstract: Surface textures are one of a main criterion for reducing wear and friction between mating surfaces. Influence of the surface texture on the tribological properties of cutting tool material was studied. Linear grooves were textured on the High Speed Steel (HSS) by electro-discharge process using EDM. The HSS pins are wear-tested by pin-on disc wear test method using D3 die steel as disc component. The results show that textured surface shows less wear rate on comparing with non-textured surface even during high temperature and high load conditions. This effect on wear is mainly due to reduction in surface contact area between the mating wear surfaces also effective transfer of wear debris from the wear medium.

Abstract: In the present work systematic study has been conducted to investigate the matrix properties by introducing nanosize Al₂O₃ (particle size 100 nm, 0.5–10 wt %) fillers into an epoxy resin. High shear mixing process was employed to disperse the particles into the resin. The experimental results indicated that frictional coefficient and wear rate of epoxy can be reduced at rather low concentration of nanoAl₂O_3. The lowest specific wear rate 0.7 x 10^-4 mm³/Nm is observed for the composites with 1 wt.% which is decreased by 65% as compared to unfilled epoxy. The reinforcement of Al₂O₃ particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms.

Abstract: The results of a study of the effect of the composition "steel-nanostructured surface layer of a material with shape memory effect TiNi, TiNiCu" on wear-fatigue characteristics of the samples are reported. Formation compositions performed by plasma spraying and high-speed flame spraying. Experimental studies have shown the efficiency of the developed technologies.

Abstract: This paper helps in understanding the effects of cryogenic treatment on microstructural variation, hardness and wear behavior of Ti-6Al-4V alloy. The microstructure indicates white β-phase dispersed on the grain boundaries of dark α-phase. Cryogenic treatment at-186 °C for 10 h led to the transformation from β-phase to α-phase, resulting in coarsening of α. Hardness of the cryogenically treated sample was observed to decrease and wear loss was observed to increase; this can be attributed to the coarsening of α-phase.

Abstract: In the present study, wear performance of Al 2219-SiCp composite was investigated and the process parameters were optimized and modeled using Response Surface Methodology (RSM) technique. In the development of the model, weight fraction of the reinforcement, sintering temperature, applied normal load on the pin and disc speed were considered as model variables. Full factorial experiments were carried out and observed wear characteristics were taken as input for the model. The results exhibit good prediction accuracy of about 85% on average of all wear characteristics and percentage error was within the acceptable limits.