Papers by Keyword: Hardness

Abstract: The increasing demand for Al7075 metal matrix composites (MMCs) stems from their exceptional characteristics, which include a high strength-to-weight ratio, low density, and superior mechanical characteristics. This research focuses on strengthening the Al7075 aluminum alloy by incorporating silicon carbide (SiC) and graphite particles. The material was produced through stir casting, using constant weight proportions of 3% SiC and 7% graphite. The research investigates the machinability of the stir-casting fabricated Al7075-SiC-Gr composites through turning operations under dry cutting conditions. Key process parameters include cutting speed (520, 840, 1200 RPM), axial feed rate (0.15, 0.25, 0.35 mm/rev), and doc (0.1, 0.2, 0.3 mm) were varied to assess their impact on power consumption. Results indicate that power consumption rises with increased cutting speed and doc. Among the factors, machining speed significantly affects power consumption, contributing 2.74% to the increase in power usage. This study highlights the vital role of machining parameters in optimizing the performance of Al7075-SiC-Gr MMCs and provides insights for enhancing both efficiency and surface quality in manufacturing applications.

Abstract: The automotive industry has been challenged by the rising need for lighter, environmentally friendly, low-emission, and low-energy consumption vehicles. Aluminium is regarded as a viable alternative to the heavier materials presently used in manufacturing automobiles due to its desirable characteristics. A review of the application of hybrid aluminium matrix composites (HAMCs) and aluminium matrix composites (AMCs) in the automotive sector is discussed in this paper. An overview of the properties and applications of fiber-reinforced, discontinuous, and particle-reinforced AMCs and HAMCs is given. Due to their superior mechanical, tribological, and physical properties, aluminium composite materials have emerged as the material of choice for most engineering applications. A discussion of the importance of proper selection of materials is also presented. The potential applications of AMCs and HAMCs in the automotive industry, i.e., brake discs and drums, cylinder blocks and liners, pistons, crankshafts, connecting rods, brake calipers, turbo heat exchangers, and others, are also addressed in this review. Recent trends and trends forming in aluminium use in automotive applications are also determined through the assessment.

Abstract: Aim: This research evaluates the strength and stability of hemp, kenaf, and coir fiber reinforced composites produced by compression molding for industrial applications. Materials and Methods: Hemp, kenaf, and coir fibers are blended with a polymer matrix and compression molded. Group 1 (Traditional) This article illustrates the effective fabrication of hybrid fiber. Ultimately stabilized to a medium percentage of resin (75%). Group 2 (Composite) hemp, kenaf & coir blended fiber source more tensile, compressive strength and minimum water absorption rate and wear behavior. Result: The best were the kenaf composites, then hemp water resistance, and they all possessed good thermal stability. Compression molding assisted in enhancing fiber bonding. Conclusion: Compression molding improved the adhesion of fiber and matrix. Kenaf composite exhibited maximum strength, hemp exhibited maximum water resistance, and all of them exhibited good thermal stability.

Abstract: Lightweight steel structural systems like trusses or built-up beams, made of thin gage steel elements, are highly efficient, with ease of handling and construction. Self-drilling screws are commonly used for connecting thin-walled elements, but the time and manpower required for numerous connections necessitate an improved solution. One possible solution is to use welding technology, but the conventional methods are not suitable for joining thin sheets. Manufacturing defect-free, mechanically sound welding joints remains challenging due to defects like porosity and undesired microstructural phases in the heat-affected (HAZ) and fusion zones (FZ). Conventional welding processes increase heat input, causing difficult challenges. Brazing, a relatively new joining process, offers the advantages of lower heat input for thin and zinc-coated steel sheets. Therefore, the paper aims to present the effect of MIG brazing parameters on the macro-and microstructural properties of Cu-Al-based weld seams manufactured for joining thin sheets with thickens in the range of 0.8-2 mm. The weld seams were manually fabricated using a MEGAPULS FOCUS 330 compact equipped with TBI XP 363S/4m welding torch, focusing on optimal welding regimes. The macro-and microstructures of the joints were evaluated along with the mechanical properties in terms of hardness, confirming that MIG brazing is a promising method for manufacturing lightweight steel structural systems.

Abstract: The mechanical properties of anodic oxide films of Nb, Ta and Zr were studied by the nanoindentation method. Anomalously high elastic recovery after deformation was observed for oxides with thickness of 20 nm. An analogue of this behavior can be elastic membrane fixed on soft base that does not prevent the membrane from bending. Increase of the oxide thickness to 300 nm reduced the effect associated with the high elasticity of oxide and easy deformation of the soft metal substrate, and was accompanied by an increase in the plastic component of deformation, which is similar to the behavior of ceramic materials with low elastic and significant residual plastic deformation.

Abstract: The present work includes an investigation of the effect of α-alumina nanoparticles addition to aluminum-based nanocomposites on its mechanical properties and finding the optimal value of alumina nanoparticles that give the best properties. Experimental work includes manufacturing samples of aluminum-based nanocomposite reinforced with alumina nanoparticles by powder metallurgy- hot forging process. Mechanical properties were tested. The results show an increase in hardness and compression yield strength with increasing the weight percentage of alumina nanoparticles, while the wear rate decreased to certain percentages of addition and then increased again. From the experimental results, multiple regression analysis methods have been used to obtain an empirical equation for predicting the mechanical properties and describe the behavior of hardness, compression strength, and wear rate. Genetic Algorithm Optimization was applied to find the optimum value of alumina nanoparticles weight percentage which gives good mechanical properties.

Abstract: The efficiency, precision, and expected lifespan of mechanisms and machine components (such as ball bearings, couplings, and gauges) are significantly influenced by the quality of the materials used. Thus, it is essential to select materials that offer well-defined hardness and stability throughout the product's lifetime. This paper examines the heat treatment applied to 100Cr6 steel to achieve precise hardness in the range of 230–390 HV10, while also meeting requirements for stability and uniformity over the product's lifespan.

Abstract: Modern engineering components require composites that are robust, lightweight, and inexpensive as integrated particulate for solid strengthening and corrosion resistance alloy. This study envisions a snail shell particulate (SSP) as a potential biofillers on aluminium alloy due to its inherent characteristics. The fabrication of the developed alloy was done through liquid stir casting method with determination to examine the correspondent physical, optoelectrical, electrochemical, and microstructural behaviour for chemical application. Composite infringement varies from 10% - 25% SSP after optimization using design of experiment. The result of electrochemical analysis showed a notable decrease in corrosion rate with increased SSP content from 12.06 mm/yr, of control sample to (75Al-25SSP) which had a corrosion rate of 7.59 mm/yr, resulting in a 40.1% drop-in degradation rate. Notably, microhardness properties increase from 28.1 to 45.5 HRB as a result of solid strengthening characteristics of doped fillers. Opto-electrical assessment demonstrated decreasing resistivity with higher SSP content, indicating improved current flow resistance. The microstructural properties showcased SSP's distinctive dispersion with few micro pores. The intermetallic phases confirmed their integration into the metal matrix by providing an enhancing adhesion and solid crystalline structure.

Abstract: This study aims to predict the hardness of electrodeposited Ni-W alloy coatings by combining machine learning methods based on a small dataset, with the goal of streamlining the trial-and-error process and reducing experimental costs. In this study, 11 features comprised of electrolyte compositions and process parameters (including current density, pH value, bath temperature, and agitation) were utilized as input parameters, with coating hardness serving as the target value. Two machine learning models (KNN and Elastic-Net) were employed to predict coating hardness, and hyperparameters were tuned using Randomized-Search CV (CV=5). The results demonstrate that the KNN model exhibits the highest predictive accuracy, with R²=0.942 and RMSE=0.0658. The SHAP method was used to analyze the importance of features and their impact on hardness. It is found that bath temperature, current density, and ammonium chloride concentration have the most significant influence on coating hardness. This study demonstrates how machine learning can enhance electrodeposition to predict coating hardness, offering insights for improving Ni-W alloy coatings in mechanical applications.

Abstract: Advanced high-strength steels (AHSS) have their current applications directed mainly to the automotive industry, where they use modern metallurgical techniques to develop microstructures with retained austenite, which leads to an improvement in the combination of strength and ductility through transformation-induced-plasticity (TRIP). The main priority of the research work will be a detailed examination and optimization of the heat treatment parameters of medium-manganese steels, specifically by the Quenching and Partitioning (Q&P) method and the expansion of experimental data related to the increase of wear resistance of these materials. The issue of the application of medium-manganese high-strength AHSS steels in the field of tribology is currently very relevant. Mid-manganese AHSS steels, which show significant wear resistance, have the potential to replace traditional Hadfield Mn steels that contain 10-14 wt. % manganese. With the help of specifically designed heating and cooling cycles, it is possible to improve their wear resistance through metastable retained austenite, which has significant potential in demanding industrial environments. This scientific study examines the possibilities of increasing the economic efficiency of the production and use of AHSS steels in various industrial areas and at the same time reducing costs compared to expensive wear-resistant steels. A key aspect of the research is the experimental evaluation of heat treatment optimization to maximize resistance to mechanical damage and extend the life of materials in various applications.