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This study investigates the tribological behaviour of Al-20Mg2Si composite having potential applications in automobiles. A pin-on-disc apparatus was employed to assess its performance under diverse operating conditions relevant to automotive components. These conditions encompassed variations in sliding conditions (dry and lubricated), temperatures (ranging from 30°C to 200°C), and loads (20N, 40N, and 60N), with a focus on understanding their influence on wear characteristics, mechanisms, wear maps, and surface topography. The findings emphasize the pronounced impact of test conditions on wear properties. Dry sliding conditions showed a substantial increase in both cumulative wear and friction coefficient, rising by 13.17 and 1.47 times, respectively, from the 30°C test to the 200°C test with a 60N load. Conversely, lubrication yielded significantly lower cumulative wear and friction coefficients, measuring only 0.07 and 0.15 times those observed during room temperature dry sliding conditions. Surface roughness analysis confirmed that higher loads and temperatures resulted in increased roughness, while lubrication effectively reduced surface roughness. FESEM analysis of worn surfaces and debris revealed that under dry sliding at room temperature, the primary wear mechanism was abrasive, with secondary mechanisms being oxidative and adhesive wear. In contrast, at high temperatures during dry sliding, the primary mechanism shifted to adhesive wear, accompanied by secondary mechanisms including delamination, oxidative wear, and plastic deformation. Wear map analysis showed that at room temperature, wear changed from severe to moderate to mild as sliding distance increased. However, with increased temperature and load, wear shifted from mild to moderate to severe.

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This study utilised the gravity casting method to modify hypoeutectic Al-7.6Si alloys with Zr at varying weight percentages (0.1%, 0.2%, and 0.3%). The unmodified alloy typically consists of a needle or platelike eutectic silicon within the dendritic α-Al phase. The addition of Zr increases the liquidus temperature of the alloy and results in the formation of ZrSi and ZrSi2compounds, which act as nucleation sites for both the eutectic Si and α-Al grains. As a result, the needle or platelike eutectic silicon transforms into a fibrous structure with a more uniform distribution, and the α-Al phase becomes finer and globular. These microstructural changes lead to improved bulk hardness, ductility, and mechanical properties of the alloy.

This study utilised the gravity casting method to modify hypoeutectic Al-7.6Si alloys with Zr at varying weight percentages (0.1%, 0.2%, and 0.3%). The unmodified alloy typically consists of a needle or platelike eutectic silicon within the dendritic a-Al phase. The addition of Zr increases the liquidus temperature of the alloy and results in the formation of ZrSi and ZrSi2compounds, which act as nucleation sites for both the eutectic Si and a-Al grains. As a result, the needle or platelike eutectic silicon transforms into a fibrous structure with a more uniform distribution, and the a-Al phase becomes finer and globular. These microstructural changes lead to improved bulk hardness, ductility, and mechanical properties of the alloy.

ABSTRACTUtilisation of by-products of an integrated steel plant improves productivity with diverse mix of raw materials used for iron making. The strength of a briquette made with Blast furnace flue dust and iron oxide with fly ash as a binder depends upon the briquetting pressure, particle size of fly ash, fly ash quantity, and curing temperature. In this study, the effect of process variables on the strength was investigated with ANOVA. The correlation between the process parameters and the strength was examined experimentally and RSM-based optimisation was performed during the preparation of briquettes. The RSM provided optimisation with a confidence level of 95% using the CCD design. This paper demonstrates the correlation between applied pressure, particle size, fly ash quantity, and curing temperature. The developed mathematical model would help in predicting the variation in the compressive strength with the change in the level of different parameters. This model can be useful for setting the optimum value of the parameters for achieving the target compressive strength.

Utilisation of by-products of an integrated steel plant improves productivity with diverse mix of raw materials used for iron making. The strength of a briquette made with Blast furnace flue dust and iron oxide with fly ash as a binder depends upon the briquetting pressure, particle size of fly ash, fly ash quantity, and curing temperature. In this study, the effect of process variables on the strength was investigated with ANOVA. The correlation between the process parameters and the strength was examined experimentally and RSM-based optimisation was performed during the preparation of briquettes. The RSM provided optimisation with a confidence level of 95% using the CCD design. This paper demonstrates the correlation between applied pressure, particle size, fly ash quantity, and curing temperature. The developed mathematical model would help in predicting the variation in the compressive strength with the change in the level of different parameters. This model can be useful for setting the optimum value of the parameters for achieving the target compressive strength.

Blast furnace flue dust and thermal plant generated fly ash are major solid wastes coming from the two important industrial sectors. Flue dust mainly contains iron oxide and carbon. The fly ash contains mostly silica, alumina and iron oxide with small amount of lime. These materials are commonly used in making of bricks and tiles. Little amount of flue dust is used in charge material preparation for iron extraction. In this present study, fixed quantities of blast furnace flue dust (30 wt %) and pure iron oxide fines (65 wt %) are mixed with different binders such as bentonite, lime, sodium silicate, fly ash, starch, molasses, pitch and dextrin. The strength of composite briquettes was determined at green, dry and cured conditions. Moreover, the effect of the variation of fly ash quantity, fly ash particle size, briquetting pressure and curing temperature on the compressive strength of composite briquettes were also investigated. The optimized fly ash quantity of 5 wt%, fly ash particle size of 75 µm (200 mesh), briquetting pressure of 95 MPa and curing temperature of 300 °C provide maximum strength to the briquettes. The phase analysis through XRD and morphology analysis through FESEM-EDS of fly ash added cured composite briquettes were performed.

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The study investigates the microstructural evolution and wear behavior of Al–12.6Si–0.25Fe–xMn alloys (x = 0, 1, 2, and 3 wt%) in dry sliding wear experiments. Manganese (Mn) considerably modifies the microstructure by modifying primary and eutectic silicon particles, changing Fe-rich intermetallic compounds, and increasing the overall wear resistance of Al–12.6Si–0.25Fe. The microstructural investigation demonstrates the production of Al15(Mn,Fe)3Si2 intermetallic phases, as well as a more uniform Si particle distribution. Wear experiments at varied loads (20 N, 40 N, and 60 N) show that Mn addition significantly reduces wear-rates and specific wear-rates, especially at lower loads. The findings highlight Mn's significance in increasing the hardness and wear resistance of Al–Si–Fe alloys, making them better suited to automotive applications.

Products developed through the powder metallurgy route have significantly contributed to structural application, automotive, and aircraft industry in the last decades. Several research works are available on the use of pure metal powder for the development of useful products through the powder metallurgy process. The study on the physical and mechanical properties of compacted reduced composite fines produced after crushing of reduced composite briquette containing Blast furnace flue dust, iron oxide, graphite powder, and fly ash is limited. The physical property such as density of green briquettes made with reduced composite fines, and 0.5% sodium silicate has been measured as a function of compaction pressures (75, 90, and 100 MPa). The maximum density of 5341.6 kg/m3was achieved at 100 MPa pressure. The samples possessing maximum density has been sintered at different temperatures of 1100 °C, 1150 °C, and 1200 °C for 60 min, 90 min, and 120 min respectively. The density, compressive strength, and hardness were measured after sintering of the samples. The samples were sintered at 1150 °C for 120 min achieve maximum density of 6111.4 kg/m3, compressive strength of 238.72 MPa, and hardness of 109.34 VHN.

In this study, the extrusion of reduced blast furnace composite fines at elevated temperatures allows manufacturing final products with distinctive microstructure and mechanical properties. The experimental results of extrusion of the composite powder under different laboratory conditions are presented and analysed. The main objective of the study is to demonstrate that blast furnace flue dust fines can be consolidated to highly dense products through extrusion. Reduced blast furnace flue dust and iron oxide fines were compacted at 100 MPa pressure to produce 20 mm and 40 mm diameter and height, respectively, and these compacted materials were subjected to different thermal treatment temperature, namely 1100 °C and 1200 °C, respectively. The product after heat treatment was extruded by direct extrusion process at different pressures such as 175 MPa and 240 MPa, respectively, at both the temperatures. The mechanical properties such as density, compressive strength, hardness and microstructure of the final product have been reported. Quantitative and qualitative metallography has been applied within the extruded product to match with the values of the mechanical properties. The product achieves maximum density of 7.55 gm/cc after extrusion with 240 MPa extrusion pressure at 1200 °C. Furthermore, the maximum compressive strength and hardness values are 336.67 MPa and 117.42HV20, respectively, when the extrusion pressure was maintained at 240 MPa and heat treated at 1200 °C.

A novel hybrid aluminium-based nano-B4C and carbon nanofibers (CNF) reinforced nanocomposite has been developed using powder metallurgy. The microstructure and mechanical properties have been evaluated using field emission scanning electron microscopy, transmission electron microscopy, hardness, and compression testing. The microstructural analysis reveals that the nano-B4C and CNF are dispersed in the aluminium matrix, resulting fine-grained structure. The 2 vol% hybrid nanocomposite shows a 182.9% increase in compressive strength, while the 4 vol% nano-B4C composite achieves the highest hardness, 62.18% greater than pure aluminium. Tribological tests using a dry sliding pin-on-disc indicate a 53.2% reduction in wear rate for the 2 vol% hybrid nanocomposites. These findings highlight the potential application of this material in the automotive and aerospace industries, where enhanced strength and wear resistance are crucial.

Finite element analysis has been carried out to understand the effect of various processing routes and condition on the microscale deformation behavior of Al-4.5Cu-2Mg alloy. The alloy has been developed through four different routes and condition, i.e. conventional gravity casting with and without refiner, rheocasting and SIMA process. The optical microstructures of the alloy have been used to develop representative volume elements (RVEs). Two different boundary conditions have been employed to simulate the deformation behavior of the alloy under uniaxial loading. Finally, the simulated stress–strain behavior of the alloy is compared with the experimental result. It is found that the microstructural morphology has a significant impact on stress and strain distribution and load carrying capacity. The eutectic phase always carries a higher load than the α(Al) phase. The globular α(Al) grains with thinner and uniformly distributed eutectic network provide a better stress and strain distribution. Owing to this, SIMA processed alloy has better stress and strain distribution than other processes. Finally, the simulated yield strength of the alloy is verified by experiment and they have great agreement.

ABSTRACTIn the present investigation, Al–X wt-% Mg2Si (X = 0, 5, 10, 15 and 20) in situcomposites are successfully synthesised by one-step gravity casting technique. Commercially pure Al, Mg and Si are used as raw materials. Microstructural evaluation and correlation of micro- and bulk hardness properties have been studied on developing composites. The composites consist of mainly three phases: matrix (α-Al), reinforcing (primary Mg2Si) and binary eutectic (Al–Mg2Si) phase. Primary Mg2Si particles are formed by pseudo-eutectic transformation during solidification and surrounded by matrix and binary eutectic phase. It is found that Mg2Si concentration has a significant impact on morphology and volume per cent of the above-mentioned phases. Primary Mg2Si particles’ size and volume per cent increase with increasing wt-% of Mg2Si. Volume per cent of individual phases and Mg2Si concentration have great impact on hardness properties of composites. Bulk hardness increases with increasing wt-% of Mg2Si concentration, but micro-hardness of primary Mg2Si particle decreases slightly. Mg2Si concentration also has significant impact on micro-hardness of individual phases.

Ligand H4Sar(AP/AP)contained two terminal amidophenolate units that were connected by a disulfane bridge. The ligand reacted with VOSO4·5H2O in the presence of Et3N under air and provided a mononuclear octahedral oxidovanadium complex (1). X-ray crystal structure analysis of complex 1revealed that the oxidation state of the V ion was V and the VO3+unit was coordinated to an iminosemiquinone radical anion. An isotopic signal at g= 1.998 in the X-band electron paramagnetic resonance (EPR) spectrum and the solution magnetic moment μeff= 1.98 μBat 298 K also supported the composition. The formation of complex 1preceded through the initial generation of a diamagnetic VO2+–iminoisemiquinone species, as established by time-dependent UV–vis–near-IR (NIR), X-band EPR, and density functional theory studies. The UV–vis–NIR spectrum of complex 1consisted of four ligand-to-metal charge-transfer transitions in the visible region, while an intervalence ligand-to-ligand charge transfer appeared at 1162 nm. The cyclic voltammogram of the complex showed four oxidation waves and one reduction wave. Spectroelectrochemical studies at fixed potentials revealed that the oxidation and reduction processes were ligand-based.

In this research work the dry sliding wear behaviour of 6351 Al alloy and 6351 Al based composites possessing varying amount of (2–7 vol%) insitu Al4SiC4reinforcement was investigated at low sliding speed (1 m s−1) against a hardened EN 31 disk at higher loads (44 N and 68.7 N). In general, at higher loads, the wear mechanism involved microcutting and microploughing abrasion. In most occasions, Al4SiC4reinforced 6351 Al based composites exhibited much higher wear rate (lower wear resistance) than the unreinforced 6351Al alloy. This was mainly attributed to the removal of reinforcement particle through microcutting abrasion process that resulted in cavitation and subsequent microploughing abrasion for rapid removal of material from surface. This is on contrary to the author's previous research work, where at lower loads (24.5 N or below), Al4SiC4particles stood tall to enhance wear resistance of 6351 Al-Al4SiC4composite.

The microstructural morphology and wear behavior of as-cast Al–X wt% Mg2Si (X = 0.0, 5.0, 10.0, 15.0, and 20.0) composites were investigated through optical microscopy (OM), energy dispersive X-ray (EDX) spectrometry, scanning electron microscopy (SEM), and field emission scanning electron microscopy (FESEM). The dry sliding wear behavior was studied against an EN 31 hardened steel disk at four different applied loads (19.6 N, 29.4 N, 39.2 N, and 49 N) with a sliding speed of 62.8 m/min for 1 h. The optical microscopy analysis exhibits that the primary Mg2Si particles average equivalent diameter and volume fraction are increased with an increase in Mg2Si (Mg and Si) concentration in the Al–Mg2Si composite. Therefore, the bulk hardness of the composites is increased, whereas the primary Mg2Si hardness decreased because the coarser primary Mg2Si particles have less compactness. The wear resistance of the commercially pure aluminum significantly improved due to Mg2Si reinforcement, and the wear resistance is increased with the increase in Mg2Si concentration up to 15.0 wt% and then decreased at 20.0 wt%. The tested composites worn surfaces and debris exhibit adhesion, delamination, microcutting-abrasion, abrasive- and oxidation-type wear mechanism.