Materials Science Forum Vol. 1171

Abstract: The ‘one variable at a time’ method adopted in general to examine the effect of process variables on the response of any treated sample is dispensed with by adopting Taguchi method of experimental optimization using Minitab-18. The effect of simultaneous variations of time of exposure to seawater ageing, salinity of seawater and strain-rate variations on Inter Laminar Shear Strength (ILSS) of seawater immersed hand-laid-up E-glass fibre/epoxy laminated composites with 50:50 weight fraction have been, thus, statically analyzed. These factors are systematically varied within pre-determined ranges [salinity 30-40 ppt, time 30-90 days of immersion) and rate of loading (1-9 mm/min)]. The statistical methods are implemented to eliminate the likely inaccuracy of one variable at a time methods generally adopted for determination of the response variable. Inter laminar shear strength (ILSS) alterations as consequences of variations of the factors mentioned above are experimentally determined. Using these experimental values, empirical equations are developed for the response variable, the inter laminar shear strength (ILSS), adopting factorial design technique and Taguchi method with 95% confidence. To validate the empirical equation, thirty additional samples were tested with random variations of the factors within the pre-determined ranges. The corresponding ILSS values were also calculated using the developed equations. The observed and calculated responses showed a high level of agreement.

Abstract: Textile waste becomes a major concern for environmental pollution also it contributes to land fill. To address this challenge recycling and reuse of textile waste into high-value materials like natural fibre composites which provide both environmental and financial advantages in the context of a circular economy since they are lightweight, biodegradable and suitable as a substitute for synthetic fibres in a variety of applications. The objective of this research is to combine mechanical performance and environmental advantages by examining a hybrid composite composed of glass fibres and textile waste. We examine the composite's tensile, flexural, impact and elongation breaking characteristics. Five different composite samples were fabricated: one with pure resin, one consisting solely of textile waste fiber layers (T/T/T), a hybrid composite with textile waste and glass fiber arranged as textile/glass/textile (T/G/T), another hybrid with glass fiber and textile waste arranged as glass/textile/glass (G/T/G) and one composed entirely of glass fiber layers (G/G/G). The experimental findings demonstrate that incorporating textile waste/glass fibers enhances the mechanical properties of pure resin composites. The G/T/G sample exhibited a higher flexural strength compared to the T/T/T sample. However, the inclusion of textile waste was observed to reduce the composite's impact strength during impact testing. These results imply that there is promise for this hybrid material in a few industrial applications, such as construction, automotive and aerospace.

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: In this work, jute and bamboo fiber is used as reinforcement to prepare hybrid composites. The alkali treatment of both the fibers are carried out and the strength of composites prepared with the alkali treated fiber is compared with the composites made from untreated fibers. The bamboo fibers are chopped and pulverized and added to matrix while the jute fiber is used in continuous form. Tensile, flexural, impact, hardness, thermal absorptivity test is carried along with the flammability test. The tensile strength of jute –bamboo-epoxy composite (JBEC) with untreated fibers is observed to be 12.21 MPa while the tensile strength of jute-epoxy composite (JEC) with untreated fiber composite is observed to be 11.72 MPa. Further, the alkali treatment of fiber increases the tensile strength of both the JEC and JBEC by 8%. About 11.12% rise in tensile strength in JEC and 14.35% rise in JBEC is observed due to alkali treatment of fibers. JBEC with alkali treated fibers [JBEC(AT)] shows 42.5HV hardness, while JBEC shows the hardness of 40.2HV. The hardness of JEC increased from 31.3HV to 35.5HV due to alkali treatment. JBEC and JEC with alkali treated fibers [JBEC(AT), JEC (AT)] shows higher thermal absorptivity than JBEC and JEC owing to the fact that higher thermal conductivity of bamboo fibers. The JBEC(AT) shows an ignition temperature of 301°C, while JBEC starts burning at a temperature of 285.6°C. JEC starts burning at 256.56°C and JEC burns by 248.52°C.

Abstract: The acoustic and performance characteristics of natural fiber amalgam-more especially, Luffa cylindrica fiber-reinforced polymer matrix composites (PMCs) filled with dissimilar proportions of cenosphere are examined in this study. Employing the Parametric Design Language (APDL) of ANSYS simulation modelling and experimental testing, the study intends to investigate the flexural and free vibration responses of these composites. Tensile strength, flexural strength, and acoustic absorption tests were performed on four distinct composite samples that contained 0%, 5%, 10%, and 15% (C-01, C-02, C03, C-04) cenosphere filler. Results showed that the composite's stiffness and load-bearing capacity were enhanced by 10% cenosphere-filled composite with highest flexural strength, modulus, and inter-laminar shear strength (ILSS). The composite's potential for noise-reduction applications was highlighted by acoustic testing, which showed substantial sound absorption at higher frequencies. Parametric studies revealed considerable changes in mechanical responses based on differences in thickness ratio, aspect ratio, and boundary conditions. Simulation models of experimental data demonstrated close agreement with the results. The created composite offers a lightweight, affordable, and environmentally friendly substitute for conventional materials and has potential for real-world uses in sectors like soundproofing, automobile, aircraft, and construction. The study comes to the conclusion that Luffa fiber composites packed with cenosphere are ideal for the development of sustainable materials.

Abstract: Hydrogen represents a promising clean energy carrier with exceptional gravimetric energy density (120 MJ/kg) [1]. Metal hydrides offer superior hydrogen storage through chemical absorption at interstitial sites, enabling performance optimization via alloy composition [2,3]. However, Mg-based hydrides, despite their high capacity, exhibit limitations including strong Mg-H bonding and sluggish kinetics, necessitating elevated dehydrogenation temperatures (600-700 K) [4,5]. Molecular dynamics (MD) simulations provide detailed atomistic insights into mechanical behavior under hydrogenation conditions [6]. This investigation employs MD to elucidate the effects of hydrogenation on the mechanical properties of Mg-Pd-Ni ternary alloys, aiming to identify compositions with enhanced structural durability for practical hydrogen storage applications.

Abstract: A new method of pulsed current-assisted gradient heating and different-temperature rolling is proposed to address the problems of poor plate shape and difficult interfacial bonding in the preparation process of traditional Ti/Cu composite plates. Through carrying out pulsed current different-temperature rolling experiments and combining mechanical property tests with microstructural characterization, the influence law of energization time on the mechanical properties of composite plates was systematically analyzed. The results show that the interfacial shear strength of the composite plate first increases and then decreases with the energization time, reaching a peak of 148.69 MPa at 40 s. This is mainly because the temperature gradient between the titanium plate and the copper plate achieves the optimal deformation coordination at this time. Meanwhile, the tensile strength of the composite plate also reaches the maximum value of 404.61 MPa at 40 s. It can be seen that pulsed current different-temperature rolling can effectively optimize the deformation coordination between dissimilar materials and significantly improve their plastic deformation ability.

Abstract: To address the issues of environmental pollution caused by nitrogen oxides (NOx) and limitation of catalytic efficiency windows, a series of Mn-Ti catalysts were prepared for low-temperature selective catalytic reduction (SCR) of NOx with NH₃. It was found that the doped layered manganese oxide catalysts (Ti-Bir) exhibited remarkable SCR activity and superior SO₂ resistance, achieving 100% NO removal at 80°C, outperforming both the composite metal oxide MnOx-TiOx and the supported metal oxide MnOx/TiOx. Through comprehensive characterization by XRD, N₂ adsorption–desorption test, H₂-TPR, O₂-TPD, NH₃-TPD, XPS, SEM and TEM, it was found that Ti-Bir successfully formed a birnessite-type layered structure with an extensive specific surface area (317 m²/g) and total pore volume (0.49 cm³/g). It contained abundant Mn⁴⁺ species and rich surface chemisorbed oxygen represented by relatively high percentages of Mn⁴⁺ and Oα. And faster oxygen mobility and better redox properties was shown with Ti-Bir. The doping of Ti into the birnessite enhanced the Mn-Ti contact, promoted efficient electron transfer and facilitated the redox cycles of Mn⁴⁺-Mn³⁺ and Ti⁴⁺-Ti³⁺. These factors together contributed to the outstanding catalytic performance of Ti-Bir in the low-temperature SCR reaction of NO with NH₃.

Abstract: The modification of titanium dioxide (TiO₂) with zirconium dioxide (ZrO₂) supported by chitosan (CS) was carried out to obtain a binary oxide system, which should have the properties of both components such as high stability, solar propulsion, non-toxicity and good corrosion resistance. The sample with a ratio of 1:1:3 (TiO₂:CS:ZrO₂) showed the best results with a photocatalytic degradability of 99 % after 90 minutes at a pH of 7 and in 10 ppm Malachite Green (MG). Under visible light, the photocatalytic degradability of the CS/TiO₂-ZrO₂ hybrid was more than 90 %. The enhanced photocatalytic degradation of MG by hybrid catalyst beads was attributed to the synergistic effect of hybrid CS/TiO₂-ZrO₂.