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The aim of this work is to investigate the variations in microstructure, hardness, wear and surface roughness between as-cast and heat treated trace elements added A356 alloy. Alloy A was prepared by adding 1 wt.% magnesium to A356 alloy which was used as the base material for the preparation of alloys with zinc (Zn) and copper (Cu) particles as alloying elements. Other set of samples was fabricated where Cu-coated Zn and Cu were added as reinforcements to base matrix A. The microstructural analysis indicated that the addition of Zn to A356 as an alloying element had a limited effect on controlling the grain size during solidification compared to Cu. The addition of Cu as reinforcement resulted in a higher proportion of pro eutectic α-Al phase, leading to finer grain boundaries. Micro-polishing test was conducted on the alloys and composites by determining the surface roughness (Ra) value using profilometer to study the changes in surface roughness under individual load conditions of 20 and 40 N. In the as-cast condition, the addition of Cu increased the hardness by 39% and 58% over the base alloy, respectively. Age-hardening treatment significantly enhanced the wear resistance properties of unreinforced alloys and composites at both aging temperatures, especially at 100 °C. Composite samples exhibited excellent surface finish (lower surface roughness) compared to alloy samples, attributed to the presence of hard reinforcement particles. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical and microstructural properties of aluminum matrix composites (AMCs) reinforced with cobalt-coated carbon nanotubes (CNTs) and Al2024 powder, tailored for aircraft and automotive applications. Using Al7075 alloy as the matrix, composites were fabricated via stir casting, incorporating varying proportions of cobalt-coated CNTs and Al2024 powder. The electroless cobalt coating, applied at thicknesses of 4, 6, 8, and 10 µm, facilitated the uniform distribution and enhanced the compatibility of reinforcements with the Al7075 matrix. Four distinct samples were developed: pure Al7075 alloy, Al7075 with 2 wt.% CNTs, Al7075 with 2 wt.% Al2024 powder, and a hybrid composite combining 2 wt.% of each reinforcement. Microstructural analysis revealed that the 10 µm coating thickness was critical for maintaining reinforcement integrity during the melt phase, preventing crack formation and reinforcement agglomeration. Mechanical testing through vickers hardness and phase analysis using X-ray diffraction analysis, demonstrated that the hybrid composite (A3) exhibited superior hardness and reduced natural aging tendencies compared to its counterparts. Peak aging at 120 °C resulted in the formation of intermetallic compounds like CuAl2 and MgZn2, contributing to improved mechanical properties. These findings highlight the significance of optimizing coating thickness and aging conditions to enhance the performance of AMCs, making them suitable for high-performance applications in the aerospace and automotive industries. [ABSTRACT FROM AUTHOR]

Aluminium–Silicon (Al-Si) eutectic alloy matrix composites are widely used in engineering application. However, it is a well-known fact that this material is not heat-treatable. In order to take advantage of the improvement in the mechanical properties due to the heat treatment, it is essential to find a way to make the Al-Si composite heat treatable. The dissolution of magnesium in the matrix, makes the composite age-hardenable, showing improvements in hardness and tensile strength properties according to changes in aging kinetics. This study analyses the peak aging kinetics on the hardness-related property improvement according to the magnesium dissolution content in the matrix. Hence, this research focuses on the role of aging treatment on the mechanical properties, especially the hardness of stir-cast Al-Si matrix Silicon Carbide (SiC) composites with up to 1.5 wt. % Mg intentionally dissolved in base alloy. Two aging temperatures (100 and 200 °C) were pitched into the target peak hardness and peak-aged condition. A minor quantity of Mg dissolution in the Al-Si matrix SiC composite has resulted in the improvement of hardness up to 24%, and age-hardening conditions contributeed up to a 40% increase in peak hardness. Similarly, the peak aged condition tensile strength shows an increase of up to 45% during age hardening compared to the Mg-free as-cast composite. [ABSTRACT FROM AUTHOR]

Austempered ductile iron is an innovative material obtained by subjecting it to an austempering heat treatment. The wide application of this material is because its properties are comparable to those of steel, which has a much lower weight. However, the machinability of this material is always a difficult task owing to its high hardness. This problem becomes more complex when a considerable amount of Mn is added. In this study, a novel two-step austempering heat treatment was performed on spheroidal graphite iron containing different amounts of manganese. Although the novel heat treatment method helps to obtain a superior combination of hardness and impact, its effect on machinability must be determined. This study provides the results of machinability tests carried out on austempered ductile iron with various manganese contents produced using the novel method. Scanning electron microscope images of the microstructures revealed a typical ausferrite structure with no segregation of manganese at the grain boundary. This is evident from the good tool life obtained in the machinability tests. Regression equations are fitted to determine the tool life and surface roughness for machining parameters with a range of values considered in this study. The results obtained have shown that till 1 wt% of manganese alloyed austempered ductile iron can be successfully produced using the novel heat treatment method. This helps to obtain the optimum combination of strength and impact properties. [ABSTRACT FROM AUTHOR]

Green oils are plant extract oils such as Karanja, Pinnay, Coconut oil, which are non-corrosive, non-toxic and environmentally friendly, and are capable of replacing petrol oil quenchants. In this study, Pinnay oil, Karanja seed oil and their blends (equal volume in proportion) were used as quenchants. Before quenching for hardening, austenitising was performed at three different temperatures ranging from 890 °C to 950 °C. The effects of austenitising temperature and vegetable oil quenchants on the hardness, room-temperature impact toughness and microstructure of normalised 42CrMo4 steel were determined. Prior to the hardening treatment, the as-received 42CrMo4 steel was subjected to normalising treatment, which enhanced the hardness and toughness properties due to grain refinement of the as-received steel. As the oil viscosity decreases, the hardness increases with marginal alteration in the impact resistance. In all the quenching condition, with an increase in austenitising temperature up to 920 °C, there was an increase in hardness around 7% and decrease in toughness around 37%, whereas at 950 °C there was a decrease in hardness around 24% and an increase in the toughness of the steel around 47% as compared to that of 920 °C. Also, blend oil quenched specimens showed balanced hardness and impact toughness compared to Pinnay oil and Karanja oil quenched specimens. [ABSTRACT FROM AUTHOR]

This review offers a summary of the epoxy-nanoclay nanocomposites research that has been performed. Epoxy-nanoclay nanocomposites have an across-the-board variety of aerospace, defense, construction, and automobile applications. Nanoclay is one of the ideal nano-reinforcement for epoxy because of its ease of workability, environmental accessibility, well-versed chemistry, and lower cost. The significant addition of a smaller quantity of nanoclay, mostly ≤5 wt.%, may efficiently improve polymer composites' properties. This review aims to provide a state-of-the-art overview of epoxy-nanoclay nanocomposites, including their preparation methods, mechanical, hygrothermal, and wear properties. The discussion highlights the nanoclay influence on the properties listed above and the morphology of epoxy-nanoclay nanocomposites. [ABSTRACT FROM AUTHOR]

During machinability, the combination of machining process parameters and the material properties of the component to be machined plays an important role. Material properties depend upon the type of phase form present and the grain size of the formed phases, which in turn depends upon the prior treatment given to alter the initial room temperature types and form. Accordingly, spheroidization treatment was carried out on medium carbon steel (AISI1040) by altering the initial room temperature structure through normalizing and hardening treatment. Machinability experiments were performed on CNC machine by varying machining process constraints. Tool wear and surface roughness of the machined component obtained by turning were analyzed and correlated. Using Minitab and full factorial design, the ANOVA study was carried out. With the help of regression analysis, residual and main effect plots combined optimization (tool wear and surface roughness) was targeted. ANOVA result shows excellent machinability for the asbought-spheroidized condition where feed has a 67% contribution to tool wear (TW) whereas the depth of cut has a 71.91% contribution to surface roughness (SR). Also, the optimized regression values obtained for machining parameters are feed (0.39 mm/rev), depth of cut (0.6 mm), and spindle speed (780 rpm) with composite desirability of 0.8174. TW and SR experimental values for the optimized machining parameters are 0.039 mm and 2.89 µm, respectively, and the difference between the actual and optimized values is less than 5%. [ABSTRACT FROM AUTHOR]

This work emphasizes the investigation that was carried out on SiC powder reinforced Al–Si–Mg ternary alloy TIG weld composite for analyzing, predicting and optimizing the hardness using Taguchi and Response Surface Methodology (RSM). The study focused on optimizing the TIG welding parameters viz, welding current, welding speed, SiC wt.% and gas flow rate for the hardness of composite using RSM. Samples prepared with varying weight percentages of SiC (8,10,12) were subjected to the TIG welding process using ER5356 filler material. A second-order response surface model for hardness is established from experimental data. The predicted as well as measured values are fairly close by, which specifies that the established model can be well utilized to predict the hardness with 95% confidence intervals. Using such a model, one can achieve significant savings in time and cost. The signal to noise ratio of process parameters analysis shows that reinforcement quantity in the composite has the maximum ranking weightage (statistical influence 72.72%) followed by welding current (22.98%), other parameter effect is negligible. The 3D surface plot reveals that maximum hardness lies in the region obtained with the welding current of 210–220 A with 10– 12 wt.% SiC and above. From the confirmatory experiments for hardness, it is seen that the experimental and mathematical model results were found fairly with a close agreement. [ABSTRACT FROM AUTHOR]

In this article, aspects related to A319 (AlSi5Cu3) and A356 (AlSi7Mg) alloy are covered owing to their prominent role in the automotive and aerospace industries. It is important to collect overall information related to these alloys and process them so that the material properties can be improved easily in the future by the addition of various trace metallic elements such as Mg, Sr, Sc, Cu, No, Ti, B, Mn, V, Zr and Ca. The addition of Mg (up to 0.45 wt.%) has been identified as the best way to improve tensile properties. It has also been identified that Sr addition modifies eutectic Si morphology and increases tensile properties. The presence of Cu causes the formation of Al2Cu which must be taken care of with proper treatments. Ni addition reduces the effect of Fe phases, and Sc addition improves the tensile properties. Various methods that can be used to produce the alloys mentioned above, related heat treatment processes, and parameters were briefly discussed. The influences of various reinforcements, modifiers, and grain refiners are presented. Solution heat treatment is implemented to dissolve intermetallic phases and the various parameters for aging treatment, cooling rate, and temperature to be used to improve the mechanical properties are also discussed. Among the various heat treatment processes, two-stage solutionizing treatment outperforms single and triple stage treatment processes in terms of improving the mechanical properties. [ABSTRACT FROM AUTHOR]