Journal of Materials Science Research and Reviews

Applications of Titanium Alloys, Ni-Based Superalloys, and Aluminum Alloys in Powder Bed Fusion Additive Manufacturing: Process–Microstructure–Property Relationships, Defect Engineering, and Emerging Frontiers

2026-09-24T10:11:48+00:00

Powder bed fusion (PBF) additive manufacturing has emerged as a transformative near-net-shape fabrication technology for advanced metallic components across aerospace, biomedical, energy, and automotive sectors. This review establishes a processing-defect-microstructure-performance tetrahedron framework to systematically evaluate how laser powder bed fusion (LPBF) and electron beam powder bed fusion (EB-PBF) parameters govern the structural integrity and functional properties of six alloy families, with primary emphasis on titanium alloys, nickel-based superalloys, and aluminium alloys, while retaining ferrous alloys, copper alloys, and refractory metals as concise comparative cases. The thermal processing history is examined as the primary control dimension that deterministically shapes defect formation, microstructural evolution, and mechanical performance. Defect mechanisms spanning lack-of-fusion porosity, keyhole porosity, and cracking are analysed through a progressive hierarchy from energy-driven universal phenomena to material-specific manifestations. Microstructural control strategies, including solidification morphology engineering, phase transformation pathway manipulation, and grain boundary design, are synthesised across alloy systems. The mechanical performance hierarchy reveals that Ti-6Al-4V and nickel superalloys deliver the highest specific strength and creep resistance but exhibit greater sensitivity to defect-induced fatigue scatter, while 316L stainless steel and AlSi10Mg offer superior process robustness at moderate strength levels. Advanced characterisation techniques, in-situ monitoring capabilities, and multiscale simulation frameworks are surveyed as essential enablers for process qualification. Emerging frontiers in multi-material architectures, alloy design exploiting non-equilibrium solidification, and industrial scalability are critically assessed, identifying key knowledge gaps and future research directions toward qualification-ready PBF manufacturing.

Research Progress in Fiber-reinforced Microbial Self-healing Concrete

2026-09-26T12:50:20+00:00

Fibre reinforcement and microbial mineralisation address different but potentially complementary weaknesses of cementitious materials: fibres limit crack opening and sustain post-cracking load transfer, whereas microbial systems can precipitate mineral phases that obstruct transport pathways and partly restore damaged material. Their integration has therefore been proposed as a route towards concrete that is simultaneously tougher and capable of autonomous crack sealing. This critical narrative review evaluates the research progress in fibre-reinforced microbial self-healing concrete, with emphasis on whether reported benefits constitute demonstrable fibre–microbe synergy rather than parallel effects. Accessible scholarly literature was searched through 17 July 2026 and appraised for mechanistic support, experimental controls, crack-conditioning methods, healing endpoints, durability relevance and translational maturity. The evidence is strongest for polypropylene, polyvinyl alcohol and basalt fibres combined with bacterial carbonate precipitation, with emerging work on steel and natural fibres and on engineered cementitious composites. Fibres can improve healing by restricting crack width, providing bridging surfaces and, for some chemistries, promoting calcium-ion retention or mineral nucleation. Yet optical crack closure, water-tightness and mechanical recovery frequently diverge, and many studies labelled as self-healing primarily measure uncracked strength or matrix densification. Claims of synergy are further weakened by the frequent absence of factorial controls and statistical interaction tests. Encapsulation and carrier technologies improve microbial survival but introduce their own effects on porosity, workability and strength. Laboratory studies support functional recovery under favourable moisture conditions, whereas repeated cracking, realistic aggressive exposures, reinforced-element behaviour and field-scale validation remain limited. The central research need is therefore not simply higher healing percentages, but standardised, mechanism-resolving experiments that connect microbial viability and fibre-controlled crack geometry to transport recovery, structural performance, service-life benefit and life-cycle impact.

Development and Qualification of Sacrificial Anodes for Ship-Hull Corrosion Protection in Marine Environments: A Critical Narrative Review

2026-10-16T12:35:00+00:00

Sacrificial-anode cathodic protection remains integral to the corrosion management of immersed ship structures and seawater-containing compartments, yet anode selection is frequently reduced to nominal alloy capacity or laboratory electrochemical efficiency. Such a reduction overlooks the interaction between alloy activation, steel or aluminium substrates, coating deterioration, seawater chemistry, hull geometry and environmental release. This critical narrative review evaluates the development and qualification of zinc- and aluminium-based galvanic anodes for maritime service, with particular attention to ship-hull systems rather than indiscriminate extrapolation from offshore structures. Literature published principally between 2005 and 9 August 2026 was critically considered alongside foundational studies, recognised technical specifications and ecotoxicological investigations. The synthesis distinguishes three related but non-equivalent outcomes: electrochemical activity under a prescribed test, delivery of distributed protective current to a coated structure and durable protection under fluctuating service conditions. Alloying with indium, magnesium, tin, silicon or selected rare-earth elements can alter activation and dissolution morphology, but benefits are composition-, processing- and exposure-specific. Contrasting efficiencies derived from mass loss and hydrogen evolution show why apparently superior laboratory performance cannot be accepted without independent qualification. Electrical resistance, coating defects, anode location, uneven immersion and mixed-metal components create system-level constraints that alloy optimisation alone cannot resolve. Environmental evidence establishes that galvanic protection transfers metal mass into surrounding water and sediment, although bioavailability and biological response vary substantially with local chemistry and the form of the released material. A defensible development pathway therefore combines compositional control, reproducible casting, multi-method discharge testing, validated potential and current-distribution models, and field monitoring coupled with environmental assessment. The review identifies paired laboratory–field validation, realistic variable-service testing, quantitative release accounting and explicitly substrate-specific design as the most urgent research priorities. Sacrificial-anode innovation should be assessed by verified protection delivered over service life, not by isolated electrochemical indicators.

Sustainable Materials for Reducing the Environmental Footprint of Artificial Intelligence Data Centers in the United States

2026-10-16T12:41:09+00:00

Artificial intelligence (AI) is expanding data-centre infrastructure in the United States, increasing demand for electricity, cooling water, semiconductor materials and electronic equipment. This review examines how sustainable materials and integrated engineering strategies may reduce environmental pressures across the AI data-centre life cycle. It considers operational energy demand, greenhouse-gas emissions, direct and indirect water consumption, critical-material requirements, thermal management, renewable-energy integration, storage technologies and end-of-life equipment management. High-thermal-conductivity materials, electrically insulating ceramics, thermal-interface composites and phase-change materials can support heat transfer and temperature control. Direct-to-chip liquid cooling and immersion cooling offer additional options for high-density computing, although material compatibility, leakage, toxicity, durability and recyclability require careful assessment. Renewable electricity can be complemented by supercapacitors, lithium-based batteries, redox-flow systems, hydrogen and thermal storage, with technology selection guided by the timescale of power demand. Measures such as modular design, longer server service life, repair, component reuse and recovery of critical materials may reduce embodied impacts and electronic waste. The review emphasises that improvements in one environmental metric can increase burdens elsewhere, particularly across the energy–water–carbon nexus. Accordingly, the assessment of sustainable AI infrastructure requires a life-cycle perspective, transparent facility-level reporting, responsible material sourcing and coordination between materials engineering, electricity supply, cooling design and circular management. No individual material or technology is sufficient to address these interdependent impacts.

Microbially Induced Calcium Carbonate Precipitation for Self-Healing Concrete: Mineralization Mechanisms, Durability Recovery, and Functional Carriers including Solid-Waste-Derived Materials

2026-10-22T08:05:30+00:00

Microbially induced calcium carbonate precipitation (MICP) can promote in situ calcium carbonate formation within concrete pores and cracks and is therefore being investigated for autonomous crack repair and durability recovery. This narrative review synthesises peer-reviewed evidence on MICP metabolic and mineralisation mechanisms, microbial survival and protection in cementitious environments, crack-healing behaviour, recovery of mechanical and transport properties, and carrier systems, with targeted updating of the literature through July 2026. Particular attention is given to the relationship between microbial activation, reaction-transport limitations, spatial mineral deposition, and functional recovery, as well as to recycled concrete aggregate, industrial by-products, and waste clay brick as potential components of carrier design. The evidence indicates that high alkalinity, pore refinement, desiccation, and restricted water and oxygen supply can limit long-term microbial activity. Immobilisation and encapsulation improve protection, but total calcium carbonate production, visible crack closure, internal filling, and macroscopic durability recovery are not directly interchangeable measures. Direct carrier evidence is strongest for recycled concrete aggregate and selected engineered porous or coated systems; waste clay brick remains a plausible but insufficiently validated carrier candidate. Future work should prioritise long-term reactivation, deep-crack healing under realistic exposure, standardised functional assessment, life-cycle and implementation constraints, waste-derived multifunctional carriers, and coupled reaction-transport prediction.

Photocatalytic Activity of Neodymium-Based Nanocomposites for Pharmaceutical Pollutant Degradation

2026-10-22T08:12:22+00:00

Pharmaceutical contaminants are incompletely removed by many conventional wastewater-treatment processes, prompting interest in advanced oxidation approaches. This review examines neodymium (Nd)-based nanocomposites as heterogeneous photocatalysts for degrading pharmaceutical pollutants in water. It considers Nd-doped semiconductors, Nd₂O₃-containing composites, neodymium ferrites and semiconductor heterojunctions, with attention to their optical, interfacial and charge-transfer characteristics. Reported applications include the photocatalytic degradation of ciprofloxacin, tetracycline, ampicillin and ceftriaxone sodium under visible light, sunlight or simulated solar irradiation in laboratory investigations. The discussion evaluates how Nd loading, catalyst dosage, initial pollutant concentration, solution pH, irradiation conditions, surface properties and charge-carrier recombination influence observed performance. Mechanistic aspects include photogenerated electron–hole pairs, reactive oxygen species, transformation pathways and the interpretation of scavenger and characterisation measurements. Reported degradation efficiencies and apparent kinetic parameters are considered alongside mineralisation, catalyst recovery, reusability and stability. The review emphasises that percentage disappearance of the parent compound does not independently establish complete mineralisation or reduced toxicity. Differences in experimental conditions also limit direct comparisons between photocatalysts. Outstanding challenges include performance assessment in complex wastewater, Nd leaching, long-term operational stability and the reporting of irradiation and reaction parameters. Further work is needed to assess stable visible- and solar-light-responsive Nd-based nanocomposites under conditions relevant to pharmaceutical wastewater treatment.

Multi-response Optimization of Alkali Treatment and Powdered Bamboo Loading in Epoxy Composites Using Box-behnken Response Surfaces

2026-09-15T04:03:10+00:00

Aims: This study developed powdered bamboo/epoxy composites and evaluated the joint effects of sodium hydroxide (NaOH) concentration, treatment time and bamboo loading on mechanical performance and water absorption.

Study Design: A three-factor, three-level Box–Behnken response-surface design comprising 15 runs, including three centre points, was used.

Place and Duration of Study: Department of Mechanical Engineering, University of Cross River State, Calabar, Nigeria; experimental work was completed in 2025.

Methodology: Bamboo powder was treated with 0–15% NaOH for 0–9 h and incorporated into epoxy at 10–20 wt.%. Composites were fabricated by hand lay-up and consolidated under a constant 10 kg load. Tensile, flexural and compressive strengths, Shore D hardness and water absorption were measured. Full quadratic models were fitted in coded variables, and equal-weight desirability optimisation maximised the four mechanical responses while minimising water absorption.

Results: All five models were significant (four at P < .001; water absorption at P = .002), with R² values of .971–.991 and adjusted R² values of .920–.974. The strongest tested formulation, comprising 15% NaOH, 4.5 h treatment and 20 wt.% bamboo, produced tensile, flexural and compressive strengths of 79.576, 103.63 and 89.44 MPa, respectively, with hardness of 43.6 Shore D. Minimum water absorption was 2.78% at 15% NaOH, 4.5 h and 10 wt.% bamboo. The predicted simultaneous optimum was 15% NaOH, 5.68 h and 20 wt.% bamboo, with an overall desirability of .929.

Conclusion: The results demonstrate a strength–moisture trade-off and identify a model-based process window requiring confirmatory validation before structural application.

Improving the Signal of Cell Phones in Places Surrounded by Blocks of Concrete

2026-09-17T13:50:20+00:00

Dense reinforced-concrete structures can substantially attenuate cellular radio-frequency signals, creating weak-coverage and dead-zone conditions in residential and commercial buildings. This study examines engineering approaches for improving indoor cellular connectivity in concrete-dominated environments while considering signal propagation, system architecture, material selection, and implementation cost. The assessment covers distributed antenna systems, passive repeaters and consumer-grade signal boosters, network-level Wi-Fi calling, small-cell solutions, and RF-friendly construction materials. Link-budget and path-loss expressions are used to describe received power, free-space loss, log-distance attenuation, urban diffraction, building penetration loss, and multi-wall loss. The manuscript also compares active and passive distributed antenna systems in terms of coverage, scalability, signal loss, complexity, and cost, and evaluates network-layer alternatives for situations in which physical modifications are limited. Material-based strategies include low-density or aerated concretes, non-metallic reinforcement, RF-transparent glazing concepts, and non-metallic insulation systems. Bill-of-materials and deployment-cost considerations are presented for selected signal-booster, Wi-Fi-calling, and construction-material approaches. Overall, the analysis indicates that indoor coverage improvement in concrete-rich environments requires a solution matched to the available outdoor signal, building scale, network requirements, and allowable infrastructure changes. The study provides a comparative engineering framework for selecting among active wireless systems, network offloading, and material-based approaches without relying on a single universal intervention.

Investigating the Combined Effect of Cocoa-Pod Husk Ash and Discharged Engine Oil as Admixtures on Strength Properties of Concrete

2026-09-22T09:11:54+00:00

The demand for concrete in the construction industry continues to increase. This study examined the performance of concrete modified with discharged engine oil (DEO) and cocoa pod husk ash (CPHA) as admixtures, focusing on physical, mechanical, and durability properties, including density, water absorption, workability, compressive strength, splitting tensile strength, and abrasion resistance. The principal problem is not simply the availability of DEO and CPHA, but the lack of sufficient experimental evidence concerning their combined use as admixtures. This study was conducted at the AAMUSTED Construction Technology and Management Laboratory. CPHA was incorporated at 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1% by mass of cement, while DEO was added at a constant proportion of 0.066%, using a mix ratio of 1:2:4. The water-cement ratio was 0.55. Concrete specimens were cast and tested after 7, 14, 21, and 28 days of curing to evaluate workability, density, water absorption, compressive strength, splitting tensile strength, and abrasion resistance. At 28 days, the control concrete achieved a compressive strength of 31.08 N/mm², while the mix containing 0.20% CPHA and 0.066% DEO achieved 28.29 N/mm², the highest value among the CPHA replacement mixes. The corresponding splitting tensile strengths were 2.263 N/mm² for the control and 2.204 N/mm² for the 0.20% CPHA mix. At 28 days, the density of the 0.20% CPHA mix was 2414.00 kg/m³. Water absorption was 1.53% for the control and 1.23% for the 0.20% CPHA mix. For abrasion, the control recorded 0.93%, while the 0.20% CPHA mix recorded 1.32%. The study concluded that, although the control specimens generally produced the optimum results, concrete modified with 0.20% CPHA and 0.066% DEO showed the best performance among the CPHA replacement mixes and remained within the reported acceptable performance range for the investigated properties.

Hemp as Bio Fiber Material for Board Paper Applications: Laboratory Evaluation of Handsheets

2026-09-22T11:34:28+00:00

Hemp (Cannabis sativa L.) is one of the oldest fibre crops used in papermaking, predating wood pulp by centuries, and its renewed legal status under the 2014 and 2018 U.S. Farm Bills has revived interest in it as a sustainable papermaking fibre. This study evaluates Hemp fibre as a partial or full replacement for Old Corrugated Container (OCC) recycled fibre in handsheet manufacturing. Hemp stems from Cornell University were processed using two laboratory refining methods - a Kumagai Riki Kogyo Co. (KRK) pressurised refiner and a Sprout Bauer Laboratory Refiner (SBLR) - followed by screening, beating to a common 450 mL Canadian Standard Freeness, and handsheet formation at a target basis weight of 70 g/m². Blends ranging from 100% OCC to 100% Hemp, in 10% increments, were tested for mechanical, structural, and optical properties in accordance with TAPPI standard methods.

The results show that the two refining routes yield markedly different fibre characteristics: KRK-refined Hemp produces denser, less porous sheets with a higher tensile index, whereas SBLR-refined Hemp yields more open, porous sheets with superior burst, tear, and zero-span tensile strength. Blending Hemp into OCC substantially improves tensile index and brightness even at low Hemp content, with an apparent optimal reinforcement window around 20–40% Hemp; beyond roughly 50–60% Hemp, tensile index, elongation, and tensile energy absorption drop sharply and then plateau. Opacity remained near 100% across all blends, brightness increased steadily with Hemp content, and CIE whiteness showed a non-monotonic dip at intermediate ratios. These findings indicate that Hemp is a viable supplementary fibre for recycled paperboard, with the pulping route selected according to target end-use properties, pending further pilot-scale validation.

Formulation of Bio-based Aqueous Digital Inks using Palm Kernel Oil and Jatropha Oil-derived Ethoxylates: Rheology, Dispersion Stability, and Print Performance

2026-10-05T13:38:37+00:00

This study evaluated aqueous digital inks formulated with nonionic ethoxylated surfactants derived from palm kernel oil (PKO) and Jatropha oil. The surfactants, previously optimised by fatty-alcohol ethoxylation, had hydrophilic-lipophilic balance values of 11.0 and 10.8, respectively, and were incorporated into pigment-based aqueous ink systems containing humectants, co-solvent, binder, biocide, and deionised water. Molecular-weight distribution, material-efficiency metrics, rheological behaviour, surface tension, zeta potential, pH, density, nozzle open-time, and print quality were assessed and compared descriptively with a commercial reference ink containing a synthetic surfactant. Gel permeation chromatography gave polydispersity indices of 1.05 for the PKO-derived ethoxylate and 1.08 for the Jatropha-derived ethoxylate. Based on the reported process mass balances, reaction mass efficiencies were 92.4% and 89.6%, while recalculated E-factors were 0.08 and 0.12 kg waste/kg isolated surfactant, respectively. Both ink formulations showed Newtonian flow within the tested shear-rate range, with viscosities of 8.42 ± 0.15 and 9.12 ± 0.22 mPa·s. Surface tensions were 29.1 and 30.8 mN/m, and zeta potentials were −38.4 and −35.2 mV for the PKO- and Jatropha-based inks, respectively. The PKO- and Jatropha-based inks produced optical densities of 2.15 ± 0.04 and 2.08 ± 0.05, adhesion ratings of 5B and 4B, and water-resistance values of 94.5% and 91.2%. No nozzle failure was observed during the 30-min decap test for either bio-based formulation. Under the conditions examined, both formulations exhibited physicochemical and print-performance characteristics close to the commercial reference, supporting further evaluation of vegetable-oil-derived ethoxylates as functional surfactants for aqueous digital inks.

From Textile Waste to Packaging Board: Pilot-Scale Evaluation of Denim Fibers in Recycled OCC Furnish—Part II (Continuous Production on a Laboratory Fourdrinier Paper Machine)

2026-10-14T12:10:09+00:00

Growing consumer demand for plastic-free packaging and tightening environmental regulations are driving the paper industry toward alternative, recycled fibre sources. Post-consumer textile waste, particularly 100% cotton denim, represents an underused fibre resource. This study evaluated the use of jeans denim fibres (JDF) as a partial replacement for old corrugated container (OCC) fibre in recycled board production on a 12-inch (304 mm) laboratory Fourdrinier Paper Machine (LFPM) at SUNY-ESF. Denim pieces were disintegrated in a Sprout Bauer laboratory refiner, screened through a 150 µm screen plate (87.5% usable fibre yield), and refined in a Valley beater to 450 mL CSF. OCC was pulped and refined to 440 mL CSF in a conical Jordan refiner. Board with a target basis weight of 162 g/m² was produced at OCC/JDF ratios of 100:0, 90:10, 80:20, 70:30, and 60:40 without wet-end chemicals. It was tested for structural, mechanical, surface, and optical properties according to TAPPI standards. Increasing JDF content reduced basis weight by 22% and caliper by 25%, whereas air resistance increased by 41%, indicating a denser sheet. Zero-span strength increased by up to 38% and tensile index by up to 24% (MD), confirming the high intrinsic strength of the denim fibres. Short span compression index peaked at 10–20% JDF. In contrast, elongation and tensile energy absorption decreased by up to 56% and 64%, respectively, at only 10% JDF and did not recover. Burst index declined by up to 32%. Together, these results describe a stronger but more brittle sheet. Optical properties improved consistently: brightness increased by 37%, CIE whiteness improved by 55%, and red and yellow tints decreased, with most gains reached by 20–30% JDF. Overall, a 10–20% JDF substitution offers the most balanced combination of compression strength, surface smoothness, and appearance. However, the early loss in toughness may limit higher JDF use in impact-sensitive applications unless offset by refining or additive strategies.

Investigation of Some Properties of Calabrian Pine (Pinus brutia) Wood Heat-Treated in Accordance with ISPM 15 Standard and Used in Pallet Manufacturing

2026-10-19T06:04:33+00:00

Wooden pallets have become extensively used for logistic purposes worldwide. Because of its delicate structure and a food source for creatures, it is important to sterilize it during international trade of commercial goods which are used for stacking elements. In this context, the ISPM 15 standard must apply to those pallets before the topic of international transportation. Regarding this issue, heat treated Calabrian pine woods which were subjected to wooden pallet manufacturing, according to the ISPM 15 standard, were evaluated in terms of physical and optical properties, especially the changes in color values and Shore D hardness properties. However, heat-treated wood samples show, each stimulus value varies independently of the others, and no consistent trend emerged. The heat-treated wood samples show higher variation directionally and tangent surfaces usually show higher changes (darkening) rather than radial surfaces. It was found to be ΔX(t1-r1): 11.47% for X stimuli, ΔY(t1-r1): 12.20% for Y stimuli and ΔZ(t1-r1): 18.15% for Z stimuli, in that order. It is worth noting that Y and Z stimulus values are higher than X stimuli for control samples, while heat treatments impact all color properties and are higher than radial surfaces at similar conditions. It was determined that the lightness (L*) of the wood samples decreased on both surfaces following heat treatment. It decreased on the tangential surface by 2.04 units, while that on the radial surface decreased by 6.61 units. Regarding a* (red-green) color parameter, calculations showed that tangential surfaces shifted toward red (+a*), while radial surfaces shifted toward green (-a*). A combined evaluation of all three color parameters revealed that the radial surface color distribution of control samples was more homogeneous and varied within narrow limits, whereas tangential surfaces exhibited greater heterogeneity and wider ranges of variation. The heat treatment increased hardness values for both surfaces. The greatest increase was measured on the tangential surface, reaching 21.72 (Shore D units), a 126.3% rise compared to the control, followed by the radial surface, which showed a 9.33% increase. Regarding gloss properties, the surface gloss values of the wood were found to be very low (matte surface, <5 GU); however, while the heat treatment was observed to increase gloss on tangential surfaces, a decrease was noted on radial surfaces.

Structural, Morphological, and Optical Characterisation of Tin Dioxide Powders with Nominal Manganese Additions Prepared by an Aqueous Sol–Gel Route

2026-10-22T07:57:54+00:00

Tin dioxide (SnO₂) powders designated as undoped or as nominally containing 0.2 or 0.4 wt% manganese were prepared by an aqueous sol–gel method and examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–visible spectroscopy. The diffraction patterns display reflections consistent with tetragonal rutile SnO₂, and the micrographs show irregular, agglomerated particulate features. A spectrum assigned to a Mn-containing specimen includes signals attributed to Sn, O, and Mn. The crystallite-size values tabulated for the three nominal groups are 76.87, 212.02, and 76.90 nm, but peak-broadening information required to reproduce them is unavailable. The synthesis designations of 0.2 and 0.4 wt% Mn are inconsistent with the 2 and 4 wt% labels in the analytical figures. Furthermore, the tabulated lattice parameter for undoped SnO₂ conflicts with its indexed diffraction peak, and the reported optical-gap estimates lack supporting fit data. Accordingly, the measurements document rutile-compatible diffraction and qualitative morphology, whereas manganese-dependent structural and optical changes cannot be quantified reliably.