Materials and Technology

EFFECT OF CERAMIC MICROSPHERES ON EPOXY POROUS SOUND-ABSORBING MATERIALS

Mei Li — 2026-07-22

In order to study the effect of ceramic microspheres on the sound absorption, sound insulation, abrasion resistance and tensile properties of the material, specimens with proportions of ceramic microsphere components of (0, 20 and 40) % were prepared for the experiments. The results show that an appropriate addition of ceramic microspheres can improve the pore structure of the material and enhance its sound absorption; however, excessive addition can block the pores and consequently degrade the material’s performance. Comparing the sound absorption and sound insulation performance of three groups of samples, it was found that EM-0 and EM-20 exhibited better sound absorption performance. The sound insulation of EM-20 containing ceramic microsphere material increased from 20.64 dB to 22.7 dB compared to EM-0. Therefore, the addition of ceramic microspheres improved the sound insulation performance of the sound-absorption material. According to physical performance tests, the compressive strength of the EM-20 sample is 0.85 MPa, the tensile strength is 0.6 MPa, the wear is 0.335 g/cm², the average porosity is 71.5 %, and the water absorption is 45.9 %. Therefore, the density of the sample is relatively low, making it easy to transport. From this, it can be concluded that ceramic microspheres can optimize the overall performance of materials, and the most suitable amount of ceramic microspheres added is 20 %, achieving the best sound absorption effect.

Ni0.4Cu0.6Mn2O4 SPINEL OXIDES: POTENTIAL FOR HIGH-TEMPERATURE FUEL-CELL APPLICATIONS

Nur Syafa Qahiera Abd Halim — 2026-07-22

Ni_0.4Cu_0.6Mn₂O₄spinel is investigated as a potential multifunctional material for solid-oxide fuel cell (SOFC) applications due to its structural stability, mixed ionic–electronic conductivity, and catalytic activity. This review examines the crystal structure, methods of synthesis, and electrochemical behaviour of Ni–Cu–Mn spinel, with the emphasis on the relationship between cation distribution, defect chemistry, and performance. The spinel structure enables electron transport through small polaron hopping, although conductivity and catalytic efficiency remain lower than conventional Ni–YSZ and perovskite electrodes. The effects of synthesis parameters, including calcination temperature and mixing time, on phase purity, particle morphology, and catalytic behaviour are critically analysed. In addition, the catalytic properties for the fuel-oxidation and oxygen-reduction reactions are discussed, highlighting the limitations in polarization resistance and reaction kinetics. Stability considerations, including resistance to carbon deposition and chromium poisoning, are evaluated, although the long-term durability data remain limited. Strategies such as doping, composite formation, and microstructure engineering are identified as potential routes for performance enhancement. However, current studies lack standardized electrochemical validation and full-cell testing. Future work should focus on establishing structure–property–performance relationships and long-term evaluation under realistic SOFC operating conditions.

EXPERIMENTAL STUDY OF THE EFFECT OF NOTCH DEPTH ON FATIGUE FAILURE OF TC4 TITANIUM ALLOY

Guifeng Yu — 2026-07-22

Notch size is a critical factor influencing the fatigue behavior of titanium alloys. This study investigates TC4 titanium-alloy notched specimens under three distinct notch depth conditions through fatigue testing. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) are employed to analyze the microscopic morphology of fracture surfaces and grain boundary evolution. The results demonstrate that as the notch depth increases, ductile fracture characteristics diminish progressively. The intensified stress concentration induced by deeper notches reduces intergranular bonding strength, leading to significant alterations in grain orientation distributions and boundary angles within individual fracture surfaces. Building upon the Basquin model, a modified life-stress correction equation incorporating notch depth as a primary influencing factor is proposed. This enables the construction of S-N curves for TC4 titanium alloy under varying notch depth conditions. Furthermore, systematic characterization of fracture-surface morphology evolution reveals that notch depth amplifies stress concentration effects while constraining plastic deformation capability. The findings provide theoretical insights for optimizing structural design and establishing a scientific foundation for lifetime assessment of TC4 titanium alloy components. This research holds significant theoretical implications and a practical value for ensuring operational reliability and durability evaluation of TC4 titanium alloys in critical engineering applications.

WIRELESS AND FLEXIBLE PIEZORESISTIVE PRESSURE SENSOR BASED ON MXENE-DECORATED ZIF-67/PAN HIERARCHICAL NANOCOMPOSITES INTEGRATED WITH PASSIVE RFID

Yage Wang — 2026-07-22

Existing flexible sensors often face inherent trade-offs between mechanical stability and signal linearity, compounded by the 'wiring bottleneck' that restricts mobility. This study presents a robust, flexible piezoresistive sensor based on a MXene-decorated ZIF-67/Polyacrylonitrile (PAN) nanocomposite, integrated with a passive Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) tag for battery-free wireless monitoring. By leveraging the high electrical conductivity of MXene (Ti3C2Tx), the hierarchical porous architecture of Metal-Organic Framework ZIF-67, and the mechanical compliance of PAN nanofibers, the sensor achieves a synergistic sensing architecture. Spectroscopic and porosity analyses confirmed the strong chemical coordination between ZIF-67 nodes and the PAN fiber matrix. This interaction constructs a stable hierarchical scaffold that effectively prevents irreversible MXene restacking, reducing the Relative Standard Deviation (RSD) of the response signal from >80% (pristine MXene) to ~15% at low pressures and <2% at higher pressures for the nanocomposite. The sensor demonstrated exceptional signal fidelity and superior durability, maintaining 92.4% of its initial response after 3,600 mechanical cycles and retaining 91.7% of its electrical conductivity after 30 days of ambient exposure. Furthermore, wireless strain data acquisition was successfully achieved using an Impinj Speedway R420 reader with a read range of 10 cm. While shorter than logistics tags, this range is optimized for secure, near-field personal health monitoring, utilizing Received Signal Strength Indicator (RSSI) modulation. This work demonstrates the feasibility of integrating MOF-enhanced MXene composites with passive RFID technology, offering a scalable solution for reliable applications in wearable health devices and structural health monitoring (SHM).

STUDY ON THE SYNTHESIS AND PHOTOCATALYTIC PROPERTIES OF Nd-DOPED ZnO MICROPARTICLES

Shu Cui — 2026-07-22

The photocatalytic performance of ZnO with a porous particulate morphology was effectively enhanced via doping with the rare earth element neodymium (Nd) under optimized synthesis conditions. Doping precursor Nd(NO₃)₃·6H₂O was introduced to fabricate a series of Nd/ZnO composites with varied Nd doping concentrations. Structural characterization confirmed that Nd was successfully incorporated into the ZnO lattice and was present in the Nd³⁺ valence state. Nd doping was found to efficiently inhibit the grain growth of ZnO, resulting in the formation of porous particles with smaller and more uniform sizes. During the photocatalytic process, the valence state of Nd ions in the composites was reversible between +3 and +2, which enabled the effective trapping of electrons in the conduction band, and reduced the spontaneous recombination of photogenerated electron-hole pairs, thus significantly improving the photocatalytic performance of the material. The degradation rate of the optimal Nd-doped sample was 2.7 times that of pristine ZnO.

THERMOMECHANICAL RESPONSE OF AS-CAST, HOMOGENISED AND EXTRUDED FORGING-GRADE 7075 ALLOY

Matija Arzenšek — 2026-07-22

The hot deformation behaviour of aluminium alloy EN AW-7075 was investigated in three material states: as-cast, homogenised and forging-grade, over a temperature range of 300–500 °C and strain rates of 0.01–10 s^–1. Compression tests were performed on cylindrical specimens using a Gleeble 3500P thermomechanical simulator. Using correction methods, the results were curated for modelling applications, providing simulation-ready data. As stationary conditions were observed at ε = 0.4 and ε = 0.8, further analysis was conducted on state variables such as strain-rate sensitivity (m), temperature sensitivity (s), activation energy (Q) and instability (n), for which maps were constructed. The analysis of metallurgical state variables provides insight into the optimal processing domains for the EN AW-7075 wrought aluminium alloy.

MICROSTRUCTURE AND FRACTURE MECHANISM OF WIRE ARC 316L STAINLESS STEEL WELDED JOINTS

Hang Dong — 2026-07-22

This study investigates TIG-welded joints of wire arc additively manufactured 316L stainless steel. A pronounced <001> texture occurred in the fusion zone, with the strongest texture intensity observed in the columnar dendritic region, while the fusion zone center consisted of equiaxed grains with random orientations. The heat-affected zone exhibited a significant ‘thermo-mechanical’ effect, with high-angle grain boundaries decreasing from 91 % to 56 %. Non-uniform microhardness was observed, with the minimum in the columnar dendritic zone. The joint achieved an ultimate tensile strength of 378.6 MPa. However, the dimples on the fracture surface were predominantly shallow and heterogeneously distributed, indicating constrained ductility despite the ductile fracture mode.

EXPERIMENTAL INVESTIGATION INTO THE UNCONFINED COMPRESSION STRENGTH OF SILT TREATED WITH XANTHAN GUM

Xunan Li — 2026-07-22

To address the engineering challenges of low strength and poor water stability in low liquid limit silt, this study investigated the improvement effect and reinforcement mechanism of xanthan gum through laboratory experiments. Unconfined compression tests were conducted on specimens with seven xanthan gum dosages ranging from 0 to 3.0 % at 0.5 % increments. Scanning electron microscopy was employed to observe microstructural changes. The results indicated that xanthan gum significantly enhanced the unconfined compressive strength of low liquid limit silt. A strong exponential relationship was observed between strength and xanthan gum dosage with a coefficient of determination of 0.98, and the reinforcement effect approached saturation beyond a dosage of 2.0 %. After modification, the stress-strain response of the silt improved, with increased tangent modulus and reduced strain at peak stress, demonstrating enhanced deformation resistance and load-bearing capacity. The reinforcement mechanism involved dual effects of pore filling and cementation, where the hydrated gel filled interparticle voids and bonded loose particles, thereby strengthening the soil skeleton. This study provided a theoretical basis and technical reference for environmentally friendly and efficient improvement of low liquid limit silt.

EXPERIMENTAL INVESTIGATION AND CHARACTERIZATION OF ALUMINIUM ALLOY (AA6063) – SILICON NITRIDE (Si3N4) COMPOSITE

Jasper S — 2026-07-22

To obtain a homogeneous material, the aluminum (AA6063)-Si₃N₄ composite was processed for microstructural characterization using the powder metallurgy technique. Powder particles were cold welded and fractured repeatedly in a high-intensity ball mill. In this work, aluminum alloy (AA6063) matrix composites of various weight percentages of silicon nitride (Si₃N₄) were produced using mechanical alloying. Among the synthetic compositions were composites of: aluminum alloy (AA6063) with 0 weight percent Si₃N₄, aluminum alloy (AA6063) with 4 weight percent Si₃N₄, aluminum alloy (AA6063) with 8 weight percent Si₃N₄ and aluminum alloy (AA6063) with 12 weight percent Si₃N₄. By looking at the milled composite powders, the properties of the aluminum alloy (AA6063), Si₃N₄ composite were investigated with an SEM. The SEM analysis confirmed the homogenous distribution of Si₃N₄ in the AA6063 matrix and no pores. The introduction of Si3N4 into the AA6063 matrix led to the enhanced mechanical properties and low porosity in the composites.

STRENGTH PERFORMANCE OF HIGH-STRENGTH GEOPOLYMER CONCRETE INCORPORATING CERAMIC TILE AND CONCRETE WASTE FOR IN-SITU APPLICATIONS

Karthiga Shenbagam Natarajan — 2026-07-23

This paper explores the possibility of using ceramic tile waste (CETW) and concrete waste (CEW) as feedstocks in the production of alkali-activated geopolymer concrete (GPC) to be used for in-situ structural applications. Binary mixtures of CETW and CEW were made in different ratios (70/30, 60/40, 40/60, 30/70) and contrasted with ternary mixtures that contained other cementitious materials (SCMs) (metakaolin MEK, ground granulated blast furnace slag GGBFS and class F and C fly ash FA) at a 30 replacement. ASTM standards were used to examine the fresh properties, mechanical performance and microstructural behavior. The flowability was 180-210 mm and setting times were 55-180 minutes according to the ratios of SiO₂/Al₂O₃ and Na₂O/SiO₂. The maximum binary strength (48.6 N/mm², 28 days old) was attained at 40 percent CETW and 60 percent CEW (SiO₂/Al₂O₃ = 12.3; Na₂O/SiO₂ = 0.18). Ternary 30% GGBFS mixes recorded compressive strength up to 64.4 N/mm² at ambient curing, due to increased availability of Ca₂⁺ to form CASH/CSH gel. Denser gel networks in optimized mixes were microstructurally analyzed (XRD, SEM-EDS, FTIR). An assessment of sustainability reported 35–45% of the reduction of the embodied CO₂ emissions compared to OPC. These results indicate the viability of CETW and CEW-based geopolymer concrete as a viable alternative in-situ application (pavements, structural walls, and foundations).

EFFECT OF Ce AND La ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AN EXTRUDED Mg-4Sn ALLOY

Ping Wang — 2026-07-23

The effects of Ce and La additions on the microstructure and mechanical properties of extruded Mg-4Sn alloy have been investigated at room temperature. The results show that α-Mg and Mg₂Sn phases are found in the extruded T4 alloys. While the MgSnCe phase was formed after adding Ce to Mg-4Sn-1Ce. The MgSnLa phase was formed by the addition of La. Incomplete dynamic recrystallization occurred in the extrusion process of the three alloys. The second phase of the extruded alloy is broken and distributed in a semi continuous streamline along the extrusion direction, and the grain structure of the alloy is refined and presents equiaxed crystal morphology. The fiber texture with (0001) basal plane parallel to the extrusion direction (ED) was exhibited by all three alloys. Brittle fracture is the way in which extruded alloys break at room temperature. The highest tensile strength and yield strength of the extruded Mg-4Sn-1Ce alloy are 246 MPa and 183 MPa. Grain refinement and second-phase dispersion strengthening are considered to play a key role in the strength optimization of alloys.

1340 Effect of deformation temperatures on microstructure and mechanical properties in an Al containing low Si TRIP steel

Yingjie Yu — 2026-07-23

An Al containing low Si TRIP steel was subjected to different deformation temperatures in austenite non-recrystallization region during thermo-mechanical processes. The microstructural characteristics were analyzed by means of optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and electron back scattered diffraction (EBSD), and its effects on mechanical properties were investigated. The results show that lower deformation temperature strongly promotes the proeutectoid ferrite formation at the expense of bainite, which causes an increase in the amount of retained austenite (RA). Compared with the case of higher deformation temperature in austenite non-recrystallization region, the steel processed by lower deformation temperature exhibits higher elongation and excellent combination of strength and ductility because of higher fractions of polygonal ferrite and RA particles with different size that provide sustained transformation induced plasticity (TRIP) effect over a significantly wide strain range. The un-transformed RA in fractured tensile specimen has much smaller grain size and higher carbon content in comparison to the case before fracture.

KINETIC ANALYSIS AND MECHANISM OF ZINC LEACHING AND RECOVERY OF OTHER COMPONENTS FROM THE EAF DUST BY APPLYING A TWO-STEP LEACHING PROCESS

Vanja Trifunović — 2026-07-23

Due to the high content of zinc in electric arc furnace (EAF) dust, despite its classification as a hazardous solid industrial waste, it can be used as a secondary raw material for its separation. After the detailed characterization of a representative sample of EAF dust, the two-step leaching process of EAF dust was investigated for the recovery of zinc and other components. The leaching process was carried out in two steps: in the pretreatment step (water leaching) and the sulfuric acid leaching step. With defined optimal process parameters the zinc leaching rate is 90.5 %. After the applied two-step leaching process of the EAF dust, the resulting leaching products were characterized, a kinetic analysis was performed, and the zinc leaching mechanism was determined.

EXPERIMENTAL STUDY ON BALLISTIC PERFORMANCE OF FUNCTIONALLY GRADED COMPOSITES REINFORCED WITH TiB2

Muhammed Soner Başer — 2026-07-23

This study investigates the fabrication of pure Al and Al–4%Cu ingots containing functionally graded layers (FGL) reinforced with in-situ synthesized TiB2 particles by gravitational casting, and the experimental evaluation of their ballistic performance. Ingots with varying FGL thicknesses were produced using the sedimentation technique, and their physical properties (microstructure, phase analysis, density, reinforcement volume fraction, elasticity) as well as ballistic performance were assessed through depth of penetration (DOP) tests. Al-based ingots with (5, 10 and 15) mm FGL, Al–Cu ingots with 10 mm FGL, and non-FGL Al–Cu ingots were successfully fabricated. Results demonstrate that ballistic efficiency increases proportionally with FGL thickness, with optimum performance observed in the 10–15 mm range, while the differential efficiency factor (DEF) decreases beyond 15 mm. Furthermore, an addition of 4 % Cu to the matrix alloy enhanced ballistic performance by 37.5 % compared to the 10 mm FGL sample without Cu, underscoring the critical role of the Cu addition in improving ballistic protection.

LOW-POROSITY AND LOW-OXIDATION 316L STAINLESS-STEEL COATINGS DURING HVOF SPRAYING: NUMERICAL SIMULATION AND EXPERIMENT

Nianchu Wu — 2026-07-23

316L stainless-steel coatings with low porosity and low oxidation were successfully produced via High-Velocity Oxygen-Fuel (HVOF) spraying of 10–50 µm feedstock powder, combining numerical simulation and experimental validation. A gas-solid coupled multiphase flow model incorporating oxidation kinetics, employing Computational Fluid Dynamics (CFD), was developed to simulate the HVOF spraying process. The study delved into the effects of oxygen/fuel (O/F) ratio, reactant flow rate, and spraying distance on the gas flow field parameters (pressure, temperature, and velocity) and particle in-flight behaviors (temperature, velocity, and oxidation status). Furthermore, Response Surface Methodology (RSM) was utilized to quantitatively analyze the sensitivity of these parameters on the oxide layer’s thickness. The optimum spraying parameters (OSPs) predicted by the simulation results were determined: 2.7 for the O/F ratio, 0.025 kg/s for the reactant flow rate, and 350 mm for the spraying distance. Subsequently, HVOF spraying experiments based on the OSP yielded 316L stainless-steel coatings with a porosity of 0.18 %, an oxide content of 0.52 w/%, and excellent mechanical properties. This work provides valuable insights for the production of 316L stainless-steel coatings with minimal porosity and low oxidation through HVOF spraying.

DEPOSITION ANGLE AS A CONTINUOUS PARAMETER: AUTOMATED GLAD GROWTH AND STRUCTURE–PROPERTY CORRELATIONS IN SILICON THIN FILMS

Kaddour Benyahia — 2026-07-23

This study aims to investigate the deposition angle as a continuous control parameter for tailoring the structural, optical, and morphological properties of silicon thin films grown by glancing-angle deposition (GLAD). Silicon thin films with a thickness of approximately 400 nm were deposited on glass substrates by electron-beam evaporation using automated control of the deposition angle in the range 0–80°. In contrast to conventional studies based on a limited number of discrete deposition angles, this approach enables a more systematic investigation of the progressive evolution of film properties with deposition geometry. X-ray diffraction analysis revealed a gradual decrease in peak intensity and crystallite size with increasing deposition angle, indicating a transition from relatively dense and ordered films at low angles to increasingly disordered structures at higher angles. Optical characterization showed marked angle-dependent changes in the transmittance, absorbance, and reflectance, consistent with an enhanced porosity, stronger light scattering, and a progressive shift in the optical response. Scanning electron microscopy confirmed the morphological evolution from compact and homogeneous layers to porous tilted columnar architectures as the deposition angle increased. These results demonstrate that the deposition angle is a key parameter governing the structure–property relationship in GLAD-grown silicon thin films and provide a useful basis for tailoring their properties for optoelectronic and photonic applications.

STRUCTURAL AND VIBRATIONAL PROPERTIES OF PLAL-SYNTHESIZED GaSe NANOPARTICLES ON DIFFERENT SUBSTRATES

Marjetka Conradi — 2026-07-23

GaSe nanoparticles were synthesized by pulsed-laser ablation in liquid (PLAL) using Bridgman-grown GaSe single crystals as targets. The laser ablation was performed in distilled water using a Nd:YAG laser operating at a wavelength of 1064 nm, pulse energy of 135 mJ, pulse duration of 10 ns, and repetition rate of 10 Hz. The structural, morphological, compositional, and vibrational properties of the synthesized nanoparticles deposited on glass and silicon substrates were investigated by XRD, SEM, EDS, and Raman spectroscopy. XRD analyses confirmed the preservation of the hexagonal -GaSe phase with crystallite sizes of approximately 10–30 nm. SEM observations revealed quasi-spherical nanoparticles with dimensions in the nanometer range, while EDS verified the presence of Ga and Se without detectable impurity phases. Raman measurements demonstrated the retention of the characteristic GaSe phonon modes and revealed substrate-dependent variations in the vibrational response of the nanoparticle layers. These results demonstrate that PLAL is an effective method for producing crystalline GaSe nanoparticles while preserving the fundamental structural characteristics of the parent material. The observed substrate-dependent behavior highlights the potential of GaSe nanostructures for future optoelectronic and nanophotonic applications.