Materials Science Forum

Preface

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181

Microstructural and Electrochemical Properties of CoNiV/Nb/Cr Medium Entropy Alloys

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Nicholus Malatji, Lehlogonolo Rudolf Kanyane, Praise Mpofu, Mxolisi Brendon Shongwe
Face-centered cubic (FCC) medium-entropy alloys (MEAs) are known for their excellent ductility and fracture toughness, but they suffer from relatively low mechanical strength. Alloying elements are added in FCC MEA matrix to promote the formation of hard secondary phase or intermetallic compounds that improve the mechanical performance of the alloys. In this study, the effect of chromium (Cr) and niobium (Nb) additions on the microstructural and corrosion characteristics of the CoNiV MEA matrix was investigated. A scanning electron microscope coupled with energy dispersive spectroscopy was used to analyse the microstructure and composition of the developed alloys. The corrosion properties of the alloys were evaluated using linear polarization. The alloys exhibited a dendritic microstructure with the presence of secondary phases, which is consistent with slow cooling associated with arc melting and the presence of elements with large atomic radii that upset the crystal lattice. Alloy containing Cr possessed better anti-corrosive properties than its Nb counterpart, signalling formation of a more stable Cr2O3 passive film. This layer creates a boundary between the corrosive medium and the alloy substrate to prevent further interaction.

Effects of Re and Mo Additions on the Nanomechanical Properties of NiTi-Based Alloy

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Boingotlo Innocentia Setlhabi, Uwa O. Uyor, Abimbola Patricia Popoola, Olawale M. Popoola, Chika O. Ujah
NiTi alloy has desired engineering properties with many applications, such as biomedical, aerospace, automotive, etc, where several researchers have investigated the development of ternary and quaternary alloying of NiTi to further enhance its performance for demanding technological applications. However, there are limited studies on the effects and synergy of Re and Mo on the nanomechanical properties of NiTi alloy, despite the highly recommended effect of Re on the mechanical properties of Ni-based superalloys. Therefore, this study bridged this gap by developing NiTi-Re-Mo alloy via the spark plasma sintering technique and investigating its nanomechanical properties in relation to NiTi, NiTi-Re, and NiTi-Mo alloys. It was noted that NiTi-Re-Mo has better nanomechanical responses than other developed NiTi-based alloys. For instance, the hardness and elastic modulus of NiTi-Mo-Re increased to about 28236.7 MPa and 483.4 GPa from 4460.7 MPa and 122.5 GPa for NiTi alloy, respectively. These significant increments were credited to the synergy effect of Re and Mo, the solution and hard phase precipitation strengthening of the NiTi system, which also contributed to the reduction of dislocations and improved mechanical locking of the NiTi system. This makes the alloy desirable for high mechanical strength applications.

Influence of the Preheat Temperature and Withdrawal Rate on the Microstructure of Ceramic-Cored Ds MAR-M247 Nickel-Based Superalloy

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Rafał Cygan, Konrad Wysocki, Łukasz Rakoczy
The research focuses on cored blades made from the MAR-M247® Ni-based superalloy, which were manufactured through directional solidification with varying withdrawal rates of either 3.4 mm/min or 5.0 mm/min, and shell mold temperatures of 1510 °C or 1566 °C after undergoing solution heat treatment. The characterization of four variants of the cored blades was conducted using several analytical techniques: X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The XRD analysis identified the presence of the γ matrix, the intermetallic γ' phase, MC carbides, and M5B3 phases. The dendritic regions of the cored blades consist of secondary γ' precipitates surrounded by a γ matrix, with a mean size ranging from 0.264 to 0.272 μm, depending on the fabrication parameters.

Heat-Treatment Induced Phase Stability and High-Temperature Corrosion Behavior of AlCrFeCuNi-NbX High Entropy Alloy

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Lehlogonolo Rudolf Kanyane, Nicholas Malatji, Mbongeni Tlou, Mxolisi Brendon Shongwe
This research investigates the impact of heat treatment and high-temperature oxidation on the phase transformation and performance of AlCrFeCuNi-Nb high-entropy alloys (HEAs). The alloys were produced using laser deposition and methodically heat-treated to enhance their structural stability. X-ray diffraction (XRD) was employed for phase analysis to examine phase alterations resulting from Nb addition and thermal exposure. Results indicate that Nb boosts phase stability, facilitates the production of protective oxide layers, and increases resistance to high-temperature oxidation. The enhanced alloy demonstrated exceptional oxidation resistance and mechanical properties. These findings underscore the promise of Nb-doped HEAs for engineering applications that necessitate resilient, high-performance materials capable of enduring harsh temperatures and corrosive conditions.

Welding Induced Distortion in Fabrication Processes: A Review of the Various Mitigation and Control Techniques

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Olorunshogo Benjamin Ogundipe, Olarewaju Seun Adesina, Olufemi O. Sanyaolu, Paul Igina, Rilwan A. Adebayo, Taye S. Olabamiji, Joshua B. Ajewole, Bamgbola O. Abolarinwa, Abosede J. Ogunleye
Welding is a widely used and effective method of joining metals. However, serious challenges are often encountered in the process due to welding distortion. Distortions result from the thermal expansion and shrinkage of metals during the welding process. This review paper focuses on the mechanisms associated with welding distortion and various mitigation techniques adaptable by fabrication industries. Whereas full prevention of distortion is unattainable with a finite geometric accuracy, it can essentially be controlled to minimize the undesired impact of distortion on the geometric integrity, hence increasing the manufacturing efficiency and decreasing the production cost. This paper categorizes distortions into out-of-plane and in-plane deformation modes and describes the factors which influence distortions - welding parameters, sequences, and material properties. Furthermore, a review of traditional and novel mitigation strategies, such as the optimization of welding parameters and improved determination and prediction of the welding sequence schedule. In this review, based on the synthesis of current publications, efforts have been made to guide fabrication industries in determining appropriate procedures and parameters to be selected according to job requirements, with the sole aim of offering better weld quality and lowering of manufacturing cost.

Preliminary Characterization of Calcined Eggshell and Silica as Fillers for Thermally Stable Bioplastic Production

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Nuhu Lawal, Adekunle Adeleke, Petrus Nzerem, Waliyi Adeleke, Chizoma Nwakego Adewumi, Frank Ogundolie, Seun Jesuloluwa
The limited thermal stability of starch-based bioplastics restricts their application in high-temperature environments necessitates the need to reinforce them with thermally robust fillers. This study explores calcined eggshell (CES) and silica as potential bio-based and inorganic fillers to enhance the thermal and structural performance of starch-derived bioplastics. Both materials were characterized using the Brunauer–Emmett–Teller method (BET), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis, and a Scanning Electron Microscope equipped with Energy Dispersive X-ray Spectroscopy (SEM-EDX). BET analysis revealed mesoporous structures in CES and silica, with pore diameters of 2.8 nm and 2.7 nm, and pore volumes of 0.125 cm³/g and 0.132 cm³/g, which favors filler–matrix interactions. FTIR confirmed the presence of hydroxyl and carbonate groups in CES and silanol groups in silica, which promotes compatibility with hydrophilic polymers. Thermal analysis showed both materials to be stable above 600°C, with CES decomposing into thermally inert CaO and silica, exhibiting minimal mass loss post-dehydration. SEM–EDX analysis confirmed high surface area morphologies and dominant Ca and Si elemental compositions for CES and silica, respectively. The findings support the suitability of CES and silica as effective fillers for thermally stable bioplastics, offering environmentally friendly and cost-effective alternatives to conventional additives.

A Review on the Investigation of Acetylated Starch & Silica Nanoparticles for Enhanced Oil Recovery (EOR) Application

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Jakada Khaleel, Nur Abubakar Isa, Chizoma Nwakego Adewumi, Temitayo Samson Ogedengbe, Fauziya Ramzy, Farouk Garba, Osasu Enoma Fountain
The decline in conventional oil recovery efficiency necessitates the development of advanced tertiary methods such as Enhanced Oil Recovery (EOR). This study investigates a hybrid nanofluid composed of acetylated cassava starch and silica nanoparticles for application in chemical EOR. Acetylated starch was synthesized to enhance viscosity and thermal stability, while silica nanoparticles were incorporated for their interfacial activity and wettability alteration capabilities. Comprehensive laboratory experiments were conducted to evaluate the hybrid fluid’s physicochemical, rheological, and recovery performance. Characterization using FTIR, XRD, SEM, and TGA confirmed successful functionalization and improved thermal resilience. Rheological tests demonstrated shear-thinning behavior with high viscosity retention. The hybrid fluid also achieved a 57.7% reduction in interfacial tension and altered sandstone wettability from oil-wet to strongly water-wet conditions. Core flooding tests revealed a recovery factor of 68.9%, outperforming starch-only, silica-only, and brine controls. The synergy between the polymer and nanoparticles enhanced colloidal stability, flow performance, and oil displacement efficiency under simulated reservoir conditions. The use of cassava starch as a biodegradable and locally sourced material underscores the environmental and economic viability of the formulation. These findings support the potential of acetylated starch–silica nanofluids as sustainable, high-performance EOR agents.

Prediction of Hygroscopic Properties of Untreated Borassus Fiber Using Ensemble Learning Techniques

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Assia Aboubakar Mahamat, Moussa Mahamat Boukar, Philbert Nshimiyimana
—Borassus palm or aethiopium palmyra is a palm species tree, widely spread in sub-Saharan Africa but its fruits don’t have any economic value therefore considered as waste. This study investigated the potential of Borassus fruit fibers (BFF), extracted manually from the underutilized fruit, for various applications by examining their hygroscopic properties. Scanning electron microscopy (SEM) revealed the fibers' unique features, including a relatively large diameter and high affinity for water vapor. A Dynamic Vapor Sorption (DVS) analysis with exposure time varying from 1, 2, 4 until 72h and varied Relative Humidity (from 0 to 90%) with 10% increment was carried out to examine the Sorption-desorption behavior. The characteristic hysteresis behavior of natural fibers was observed, with significant moisture uptake, particularly above 70% RH. The sorption and desorption processes were quantified, revealing a linear relationship between mass change and relative humidity. Furthermore, an Ensemble learning approach, specifically a Gradient Boosting Regression (GBR) model, was developed to predict the hygroscopic behavior of BFF. Trained on the experimental sorption-desorption data, the GBR model demonstrated excellent predictive accuracy, achieving a high R² value of 91.7% and low CV, MSE, and RMSE values (6.9 and 2.6, respectively). These findings highlight the significant influence of relative humidity on BFF moisture content and demonstrate the effectiveness of GBR as a powerful tool for accurately predicting the complex hygroscopic behavior of these fibers. Keywords—Machine Learning techniques, Ensemble Learning, Natural fiber, Hygroscopic properties, sorption/desorption

Moisture Uptake Effect on Bending and Damping Properties of Composite Sandwich

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Norman Osa-Uwagbue, Sunday Atomode, Francis Anyebe Oteikwu, Osezua Ejodame, Amadi Gabriel Udu
In this paper, the effects of seawater exposure on the bending and damping properties of fibre-reinforced sandwich structures were investigated experimentally and analytically using the residual property model (RPM). Glass fiber reinforced plastics facesheets with PVC foam core, exposed to seawater exposure until saturation was subjected to flexural and dynamic mechanical analysis tests. Key mechanical properties were used to develop an analytical residual property model. Results indicated that after exposure, while the flexural strength and modulus reduced by 20% and 19% respectively, the storage, loss moduli and tan delta increased by 7%, 20% and 12% respectively. Furthermore, the accuracy of property degradation was demonstrated for the predicted properties, thereby establishing the suitability of RPM as a cost-effective means for material property determination.

Obtaining Activated Carbon by Microwave Activation from the Solid Waste Generated in the Pyrolysis Process of Used Tires

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Yvet Loayza-Del Carpio, Jonathan Almirón, Maria Fernanda Palomino-Cervantes, Yosheff Ortiz-Valdivia, Grace Acevedo-Obando, Ronald Rosales-Meza, Danny Tupayachy-Quispe
The aim of this research is to obtain activated carbon from the solid residue generated in the pyrolysis process of used tires, using microwave technology for its activation. In the first phase, the tires were subjected to thermal pyrolysis at 575°C to obtain a carbonaceous residue (CR). This residue was then activated using potassium hydroxide (KOH) in a 1:3 ratio and exposed to a conventional microwave oven at a power of 700 W for 3 minutes without pauses, obtaining activated carbon (AC) as a result. To evaluate the adsorption capacity, tests were conducted with both carbons (CR and AC) using three concentrations of carbon, with a contact time of 300 minutes and agitation at 400 RPM. The results showed that CR achieved a maximum adsorption of 57.13% at a concentration of 0.2 g, while AC exhibited values greater than 90%. It is concluded that microwave activation is an effective and cost-efficient process to convert the carbonaceous residue from used tire pyrolysis into an adsorbent material with high arsenic removal capacity.

Ionic Conductivity and Structural Studies of Poly(Methyl Methacrylate)-Grafted Natural Rubber-Graphene Oxide Integrated with Ammonium Triflate Based Polymer Electrolytes

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Hamidah Shabri, Khairur Iman Khairur Rijal, Mimi Nur Aineen Azhari, Arina Dayana Hamede, Nurul Safiya Natasha Mohamad Sabri, Khuzaimah Nazir, Nabilah Akemal Muhd Zailani, Siti Zafirah Zainal Abidin
The performance of polymer electrolyte can be improved through various approaches, including the addition of filler and dopant salt, in which has demonstrated significant potential for enhancing performance in electrochemical applications. The purpose of this study was to investigate the ionic conductivity and structural studies of 49% poly (methyl methacrylate) grafted natural rubber (MG49)-graphene oxide (GO) integrated with ammonium triflate (NH4CF3SO3) based polymer electrolytes. The highest ionic conductivity, 4.42 x 10-6 Scm-1, was achieved with 25 wt.% of NH4CF3SO3. ATR-FTIR analysis showed a reduction in C=O peak intensity, indicating interaction between the polymer matrix and salt, while optical microscopy (OM) revealed that the 25 wt.% sample had the smoothest surface and the most amorphous structure, correlating with the highest ionic conductivity. These results suggest that nanocomposite polymer electrolytes based on MG30-GO-NH4CF3SO3 have potential for energy storage applications.

Double Scaling Electrical Transport in (Fe₃O₄)1-x/ (BaTiO₃)x Nanoparticle Composite Sinters: Variable Range Hopping and Percolation

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Hiromi Kobori, Niato Fukutome
We report double scaling electrical transport in (Fe₃O₄)1-x/(BaTiO₃)ₓ nanoparticle-composite sinters (NPCSs), where charge conduction arises from the coexistence of variable range hopping and percolation. Understanding the interplay between these mechanisms is essential for designing composite materials in which microstructural connectivity and carrier localization can be tuned for targeted electronic properties. The NPCSs were synthesized via low-temperature hydrogen reduction and sintering of α-Fe₂O₃ and BaTiO₃ nanoparticles (average diameter ~100 nm) at 500 °C for 3 h in an Ar (90%)/H₂(10%) atmosphere, yielding x values from 0.0 to 0.7. X-ray diffraction and scanning electron microscopy confirmed phase purity, the coexistence of Fe₃O₄ and BaTiO₃, and systematic grain-size evolution with BaTiO₃ content. Electrical resistivity increased with x and followed 3D Mott’s variable range hopping behavior, with ln ρ vs. T ⁻¹ᐟ⁴ (ρ: electrical resistivity; T: temperature) remaining linear and slopes increasing with x, consistent with shorter hopping lengths and enhanced carrier localization. Percolation analysis in the 150–300 K range yielded a conductivity critical exponent of ~3, significantly higher than the ~2 predicted for simple 3D percolation, indicating that geometric connectivity alone cannot explain the transport. These results provide compelling evidence that charge conduction in these composites is governed by a double scaling mechanism, in which variable range hopping and percolation coexist and jointly control electronic transport through the combined influence of microstructure and composition.

Computational Study of Ni Doping on the Thermoelectric Properties of Magnetite

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Kabir Suraj Salihu
I report a first-principles investigation of nickel-doped magnetite as a candidate for thermoelectric applications. Substituting Ni at the octahedral Fe sites preserves the inverse spinel framework while introducing Ni 3d impurity levels near the Fermi energy. Using Boltzmann transport theory in the constant-relaxation-time approximation, I calculate temperature and carrier-concentration-dependent transport properties, namely, electrical conductivity, the Seebeck coefficient, the power factor, and electronic thermal conductivity for both n-type and p-type doping. I find that conductivity increases significantly with increasing doping level, while the Seebeck coefficient shows large peaks and even changes sign at moderate carrier densities. Notably, I observed a very large power factor that exceeds that of the commonly used thermoelectric materials at higher temperatures. However, the accompanying rise in electronic thermal conductivity highlights the need for phonon engineering to limit total heat transport. These results demonstrate that Ni substitution provides an effective route to tune the electronic structure and optimize the thermoelectric performance of magnetite under realistic operating conditions.

Optimization of the Compressive Strength of 280 kg/cm2 of Concrete by Partially Replacing Cement with Ground Blast Furnace Slag and Silica Fume

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Janeth Lucero Ayra Espiritu, Yelitsa Jasmin Quispe Curo, Carlos Augusto Eyzaguirre Acosta
The partial substitution of cement with ground blast furnace slag (GGBS) and silica fume (HS) in the concrete mix has the potential to reduce the carbon footprint associated with cement production. The objective of this study is to evaluate the feasibility of this partial replacement as a strategy to promote greater sustainability in construction. The research looks at four replacement percentages with different ratios: 10% HS, 10% GGBS, a combination of 10% GGBS and 10% HS, and 13% GGBS with 10% HS. The results indicate that the mixtures obtained not only reach but exceed the required strength of f´c=280 kg/cm2 and have a reduced carbon footprint compared to conventional concrete. This highlights the environmental benefits of using industrial by-products as partial replacements in concrete manufacturing, helping to mitigate the negative impacts of cement production.

Can Emery Replace CEMII in Masonry Restoration Mortars?

Thu, 5 Mar 2026 00:00:00 +0100

Publication date: 5 March 2026
Source: Materials Science Forum Vol. 1181
Author(s): Styliani Papatzani, Nikolaos Alexios Stefanis, Anna Fanouria Kloukinioti
Under the current research project, the feasibility of reducing the carbon footprint of masonry restoration mortars was investigated, by means of replacing a part of cement with emery. A two-fold advantage is offered by following this strategy: (i) to develop more sustainable restoration mortars and (ii) to validate the use of a rock that can potentially offer greater resistance to depletion/ weathering. Emery, a naturally occurring rock was characterized via X-ray fluorescence and stereo microscopy. The reference mortar was prepared according to EN 196-1:2016, with a CEMII/B-M(P-LL)42.5R cement targeting a flow table spread of 12-16±1 mm (in accordance with EN1015-3:1999+A1). Consequently, (i) a 20% and (ii) a 50% CEMII replacement with corundum powder was materialized. The mean compressive strength was reduced, as originally intended, by approximately 50% for the 50% replacement, allowing the mortar to be used for restoration purposes, where natural, low strength materials are preferred, which not exceeding the strength of masonry stones. Interestingly, flexural strength did not fall drastically. A number of complications arise on setting the flow spread as the basic design parameter and discussion on mix design is elaborated upon and correlated with the 7-and 28-day strength tests (in accordance with EN1015-11:1999+A1). Furthermore, the pore structure of the surface of the specimens was investigated via stereo microscopy and interesting observations pave the way for more sustainable mortar design.