Rakesh Sikder

Cupola furnace slag (CFS) poses significant challenges for casting industrialists, who must navigate the complexities of its disposal to maintain operational efficiency and environmental responsibility. This study aims to investigate and implement the reuse of CFS in the construction industry which in turn creates a new method for solid waste management. This study clarifies the mechanical and durability properties of concrete that contains CFS‐coarse‐aggregates (CCA) and cupola‐fine‐aggregates (CFA), which are natural fine and coarse aggregate substitutes. To accomplish this, compressive strength, split tensile strength, water penetration, impact resistance, surface abrasion loss, and rapid chloride penetration tests were conducted. In M30 grade concrete, the experimental procedures involved varying degrees of weight replacement (0% to 40%) of natural fine‐aggregate (FA) and natural coarse‐aggregates (CA) with CFA and CCA, respectively. The experimental findings revealed that compressive strength increased with up to 20% replacement of FA, but decreased afterward. Conversely, compressive strength decreased with the replacement of CA, though up to 30%, replacement still met M30 grade concrete requirements. A leachability test was conducted to detect toxic and heavy materials in CFS. SEM, EDX and XRD techniques were also employed. Replacing FA and CA with CFA and CCA, respectively, proved economically beneficial compared to standard concrete.

Present investigation is focused on the effect of nano CuO & nano TiO₂ addition up to 4 wt% on sintering behaviour and tribo-mechanical properties of alumina ceramics. Densification study showed that bulk density of pure alumina was optimized to 94.49% at 1600 °C. Nano CuO undergoes liquid state sintering by formation of CuAl₂O₄ and improved densification to 97.74% at the level of 2 wt% addition. Whereas nano TiO₂ undergoes solid state sintering by formation of cation vacancies by Ti⁴⁺ substituting Al³⁺ in corundum unit cell. Vickers hardness and fracture toughness showed proportional relation to densification. Nano TiO₂ addition showed higher fracture toughness than the same level of nano CuO addition in alumina ceramics. 1 wt% TiO₂ addition decreases 45.57% wear rate but it is optimised to 57.68% at 2 wt% CuO addition in alumina ceramics, supported by 3D surface profilometer. Microscopic observation of worn-out surface shows that wearing out of material is caused by plastic deformation and abrasion. Significant improved mechanical properties of alumina ceramics by nano oxides addition is due to inhibition of abnormal grain growth and grain refinement (shape and size of grain becomes regular and follows a pattern instead of abnormal grain growth). Friction coefficient gradually increases with wt% of nano CuO but it shows decreasing order with wt% of nano TiO₂ addition.

This experimental work presents machinability characteristics of waste derived cupola slag reinforced aluminum metal matrix composites in solution treated condition during dry turning operations. Composites used in this work were fabricated by an economical stir-casting method using 100 μm-sized cupola slag particles as reinforcement at 0, 3, 5, and 7 wt% in an Al-4.5-Cu aluminum alloy (LM11) matrix. Post fabrication the samples have been heat treated. The physical, mechanical and microstructural characterizations are conducted to evaluate the changes in base alloy by cupola slag inclusion and subsequent heat treatment. The dry turning experiments has been performed in a conventional lathe with varying feed rate and spindle speed with constant depth of cut. Key machinability indices such as tool wear, chip thickness, power consumption, surface quality, force requirement and material removal rate (MRR) by loss of weight method have been investigated. A detailed tool wear study, along with analysis of chips have been presented for introspection of underlying cutting mechanisms. The results indicates that 7 wt% slag reinforced composites show improved physical, mechanical and machinability behaviors due to uniform slag dispersion and refinement of grains. This work establishes one of the possibilities of reusing cupola slag as an eco-friendly and cost-effective reinforcement in high-performance MMCs.