Parshant Kumar

Interfacial debonding accelerates wear in short carbon fiber–epoxy composites (V _f = 40 ± 2). Triton X‐100 surfactant (1, 2, and 3 wt.%) was applied to modulate friction and wear performance, with modified composites designated as CE‐1S, CE‐2S, and CE‐3S. Pin‐on‐disc tests (ASTM G99) against EN31 steel (58–60 HRC) were conducted at 15–25 N and 1.05–1.57 m/s. Gravimetric analysis recorded 0.85% mass gain at 1 wt.% concentration, consistent with near‐saturation adsorption behavior. At this optimal concentration (CE‐1S), steady‐state COF decreased from 0.45 to 0.29, representing a 35.56% reduction relative to the untreated baseline ( p < 0.05). The specific wear rate for CE‐1S decreased by 27.4% (to 8.68 × 10 ⁻⁵ mm ³ /N m) at 1.57 m/s and by 64.3% ( p = 0.0012) at 1.05 m/s. Surfactant concentrations above 1 wt.% were associated with excess deposition that progressively degraded tribological performance. SEM observations were consistent with a reduction in fiber pull‐out from 64 ± 9 to 22 ± 4 m, while void fraction dropped from 6.3% to 2.1%. These results suggest that 1 wt.% surfactant enhances interfacial adhesion and wear resistance.

For the busting of heat, generated in electronic packages, relevant materials need to be developed. Metal matrix composites may be considered as an option to tailor the properties of a material (Cu) by incorporating an additional phase (SiC) for fulfilling the requirements of thermal management systems. The composite (Cu/SiC) was manufactured by friction stir processing. For good interfacial strength, the biggest challenge in the fabrication of Cu/SiC composite was to abolish the reaction between Cu and SiC. Being solid in nature, the process (friction stir processing) does not allow temperature to reach the interfacial interaction. Scanning electron microscopy, electron backscattered diffraction, and optical microscopy were used to characterise the composite for microstructural features (particle dispersion, phases present). To confirm the presence of reinforcement, EDS analysis was also performed on the composite. Results indicated the presence of Cu and SiC phases in the stir zone (SZ) with uniform and homogeneous separation of reinforcements. The composite displayed higher hardness, tensile strength, and wear resistance in comparison to unprocessed copper. However, ductility decreased due to high hardness in the composite.

The intensity of radial heat flux during quenching affects the microstructural features of materials. The interface strength is also affected by the radial heat flux in the case of metal matrix composites (MMCs). Thus, the mechanical and tribological behaviour of MMCs may vary with the quenching medium. The present investigation deals with the effect of the quenching medium on the mechanical and tribological behaviour of chromium (Cr) particles reinforced Al/Cu dual matrix composites. Normal load (viz. 20, 40 and 60 N) and weight percentage of Cr reinforcement (viz. 1, 2, 3, 5, 8 and 10 wt. %) were also varied. The powder metallurgy route was followed for the fabrication of composites. The sintered composites were normalised and quenched in oil and water. The results revealed that water-quenched composites exhibited the highest hardness and compressive strength and the lowest wear. The highest compressive strength was approximately 48 MPa for 3 wt. % Cr reinforced water-quenched composites. The coefficient of friction decreased with an increase in Cr content, whereas it was very difficult to generalise the wear behaviour with respect to Cr content. The fractured and worn surfaces were analysed under a scanning electron microscope to know the fracture characteristics and dominant wear mechanisms, respectively.

In this work, Fe-2Cu-0.8C-CaF₂ self-lubricating composites with calcium fluoride solid lubricant (3 □ 12 wt.%) were examined for their friction and wear at 5 and 10 m/s, at 500 °C. Addition of CaF₂ decreased density and hardness of composites. During sliding, materials gained weight due to oxidation. Compared to the base matrix (Fe-2Cu-0.8C), composites showed lower weight gain and lower coefficient of friction. Increase in porosity with CaF₂ content increased oxidation resulting in higher weight gain and increased friction due to wear debris abrasion. Increase in speed reduced weight gain due to higher material loss. Adhesion was the dominant wear mechanism in base matrix; delamination and wear debris abrasion in composites. Temperature rise at sliding surfaces was theoretically estimated. Increase in speed increased temperature, which reduced friction due to softening and shearing of solid lubricant. Composite with 3 wt.% CaF₂ showed least surface damage and 6 wt.% showed lowest coefficient of friction, i.e., lower by 16% and 10% at 5, 10 m/s than base matrix. Tribological response of the composites to a broad range of applied parameters, viz. speed, load and temperature taken from earlier works and present work is briefly summarized. The study suggests the dominant role of CaF₂ content and the wear debris in altering the tribological response. Further, the stability of the developed composites at high temperature and high load conditions was also established. The study suggests that the developed composites could serve high-load and high-temperature applications for heavy machinery such as bearings, shafts and gears.

Despite excellent properties of aluminium silicon (Al-Si) alloys in several aircraft and automotive applications, its usage is limited because near net shape casting of Al-Si alloys may cause several defects like surface pinholes and grooves. Fabrication of components and then welding them via fusion-based welding processes imposes issues like porosity and slag inclusions which may severely degrades its properties. Thus in present study, friction stir welding (FSW) was employed for welding of hypereutectic Al-Si cast alloy. The nugget zone (NZ) of welded alloy and its as-cast counterparts were characterized for their performance in terms of mechanical and tribological behaviour. The results depicted fragmentation of α-Al dendrites, refinement and redistribution of acicular Si particles as a result of stirring with high strain rate, and improvement in mechanical properties such as ultimate tensile strength, yield strength, ductility, hardness and wear resistance as compared to as-cast alloy. It is also shown that disparate wear mechanisms occured in friction stir welded (FSWed) and as-cast alloys. A sizeable amount of adhesion with plastic deformation and delamination pits were observed for as-cast alloy, while the dominant mechanism in FSWed alloy was peeling with little adhesion.

Recently developed technique, friction stir welding (FSW) is capable to counter the issues like porosity and slag inclusion developed during fusion-based welding of hypereutectic aluminium silicon alloy (Al-Si). Studies based on FSW of aluminium silicon alloy have been reported but there is no report on hypereutectic particularly. Hence, present study was taken in to consideration to investigate the feasibility of FSW for welding of hypereutectic aluminium silicon alloy. The results revealed FSW caused breakage of α-Al dendrites, refinement and re-distribution of acicular Si-particles due to stirring at high strain rate during welding. Hardness and wear improved substantially of welded alloy with respect to its un-welded counterpart. The enhancement in microhardness and wear properties may be ascribed to breakage of α-aluminium dendrites, refinement and re-distribution of acicular silicon particles that led to hindered motion of dislocations and hence higher hardness and wear resistance.

Gas metal arc welding (GMAW) is a versatile welding technique and hence used in almost all industrial segment. The process parameters greatly affect mechanical

Friction stir processing (FSP) can be used as a tool to refine grain. Present investigation was conducted to observe the effect of FSP on microstructure and mec