High Temperature Applications Research Articles

A Comprehensive Review on Hot Deformation Behavior of High-Entropy Alloys for High Temperature Applications

A Comprehensive Review on Hot Deformation Behavior of High-Entropy Alloys for High Temperature Applications

Investigation of high-temperature wear behavior of TiN and TiAlN PVD-coated low alloy steel AISI 4140

Purpose AISI 4140 is a versatile, low alloy steel often used in various applications in mechanical systems and manufacturing processes. To mention a few in processes such as friction stir welding tooling and in engine components, temperatures above 700°C coupled with wear. Despite its versatility, it is still susceptible to wear and corrosion. A common method to address this shortcoming is physical vapor deposition (PVD) coating. This study aims to experimentally investigate the wear performance of AISI 4140 PVD coated with titanium nitride (TiN) and titanium aluminum nitride (TiAlN) at room and elevated temperatures. Design/methodology/approach Two sets of three samples were prepared. Where one sample was uncoated AISI 4140, TiN and TiAlN PVD coated, one set was tested at room temperature and the other set at 780°C for comparison purposes. The average coating thicknesses were measured, and the adhesion properties were assessed using a scratch test. Their tribological wear scars were further characterized using scanning electron microscope (SEM) energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Raman and confocal microscopy, and the results were furnished in the paper. Findings With the scratch test, the first critical load (Lc) on the TiAlN coating was 15% higher than that of the TiN coating. At room temperature, TiN had the highest coefficient at 0.61, while TiAlN was 0.39. After 1,500 s, samples showed run-in and stability. At elevated temperatures, TiAlN started with the highest friction but stabilized later than TiN and uncoated samples, which stabilized after 200 s due to titanium oxide formation. This was due to the formation of an oxidation layer caused by the thermal environment. Hence, the opposite is observed at room temperature. The findings were supported by the Raman, XRD, SEM EDS and areal topography analysis. Originality/value The results presented in the study are valuable to design engineers and researchers anticipating wear in high temperature applications. Therefore, with these results, reasonable, informed decisions can be made about specific design requirements. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0354/

Development of NiCrAl with Reactive Element Addition to Improve Oxidation Resistance at High Temperature Application

Development of NiCrAl with Reactive Element Addition to Improve Oxidation Resistance at High Temperature Application

All-Organic Aramid Films with High Temperature Resistance and Electrical Insulation by Introducing Interfacial Hydrogen Bonds.

Although aramid nanofibers (ANFs) consist of rigid poly(terephthalic acid terephthalamide) molecular chains with good high temperature resistance for aerospace and other high-temperature applications, it has poor electrical insulation properties due to internal defects. Currently, the main method to improve the electrical insulation properties is to introduce wide band gap two-dimensional (2D) fillers, such as Boron Nitride Nanosheets (BNNS) or mica flakes, but this inevitably affects the mechanical properties and optical transparency. Cellulose acetate (CA) is originated from acetylation of natural cellulose, and the higher number of hydrogen bond donors on the molecular chain enables it to interbond with many polymers. In this study, CA was introduced into ANFs films, and the all-organic aramid films were prepared by blade coating method. A high dielectric constant of 14.4 as well as a low dielectric loss (0.062 @103 Hz) were obtained, and the dielectric loss of all films was lower than that of the ANFs films, which is attributed to the introduction of interfacial hydrogen bonds that suppressed the loss. In addition, the introduction of interfacial hydrogen bonds introduced deep traps inside the all-organic aramid films, which further improved in breakdown strength from 216.11 MV/m for ANFs film to 367.8 MV/m for the 5 CA film. The prepared all-organic aramid films also showed excellent flexibility as well as high temperature resistance, and the electrical insulation performance under different extreme environments was still higher than that of the ANFs films. This study provides a method for the preparation of high temperature resistant and electrically insulating films, which have great potential applications in fields relating to high temperature circumstance.

Predicting thermoelectric performance of AlGaSbAs-based systems for thermo-photovoltaic cell applications

Abstract The development of high-performance thermoelectric (TE) materials is critical for advancing thermo-photovoltaic (TPV) technologies. To evaluate TE properties of AlGaSbAs-based systems, highlighting their potential for efficient thermal energy conversion in TPV cell applications, this paper explores and selects a new material that predict TE performance of TPV system while ensuring environmental sustainability. The study further delves into material-specific performance with a case study on AlGaSbAs, including thermal conductivity, bandgap (Eg) engineering and figure of merit using a Python simulation tool to improve the TPV cells' quantum efficiency and thermal stability. Using such a predictive computational framework, key TE parameters are quantified: figure of merit (ZT ~ 1.5–2.5), Seebeck coefficient (S: 150–300 μV/K), electrical conductivity (103–104 S/m), and thermal conductivity (κl of 0.91W/mK at 1100 K). Suitable Eg of Al0.125Ga0.875Sb0.75As0.25 (0.554 eV) ensures alignment with mid-infrared photon energies, optimizing energy conversion in TPV systems operating at 500–1200 K. Innovations include alloy engineering to enhance phonon scattering, nanostructuring to minimize lattice thermal conductivity (κl), and doping strategies to boost power factor. This study establishes AlGaSbAs as a scalable, thermally stable, and environmentally friendly material for next-generation TPV systems, providing a pathway for integrated TE and photovoltaic energy conversion solutions. The results showed that the thermal conductivity decreases with increasing temperature following a trend where it is inversely proportional to temperature which is beneficial as it suggests reduced heat loss at higher temperatures. S coefficient showed a linear increasing trend with the increasing of temperature demonstrating that the material becomes more effective at converting temperature differences into electrical voltage at higher temperatures. With controlling thermal parameters and selecting of the most suitable material, the efficiency of AlGaSbAs-based TPV cells can be significantly improved, making them more viable for high-temperature applications.

Innovating bio-lubricant design: utilizing Mordred descriptors for model development and thermal stability prediction of novel compounds

Purpose Developing bio-lubricants for high-temperature applications, such as engine operations, requires reliable thermal stability assessment. This study aims to create a predictive tool to evaluate thermal stability using existing organic compounds data. The model predicts the onset temperature (T onset) of bio-lubricant candidates derived from epoxidation with various amine nucleophiles, enhancing initial selection efficiency and reducing reliance on traditional trial-and-error methods. Design/methodology/approach Using the Python library Mordred, molecular descriptors were calculated from the SMILES structures of 126 compounds with known T onsets. These descriptors were inputs for machine learning models predicting the thermal stability of bio-lubricants. The models were evaluated on training and test data sets and validated with novel synthesized compounds. Findings The predictive model showed strong performance on the test data set, with an R² of 0.93 and a root mean square error of 17.77. In external validation, the model estimated the thermal stability of a novel bio-lubricant compound (MA-EPO) at 290.7°C, closely matching the actual T onset of approximately 300°C. Originality/value This research introduces a method for predicting the thermal stability of bio-lubricants using machine learning and open-source libraries. This approach significantly advances the field by improving the efficiency of bio-lubricant development for high-temperature applications. It provides a cost-effective and time-saving alternative to traditional experimental methods, serving as a valuable resource for researchers and developers in the bio-lubricant industry.

Effect of fine-tuned growth temperature on structural, morphological, optical, and electrical properties of Cu2O nanoparticles as candidates for supercapacitor applications

Abstract Cuprous oxide (Cu2O) nanoparticles are promising candidates for optoelectronic and energy applications due to their unique p-type semiconducting nature, optical and electrical properties. This work studies the impact of carefully controlled growth temperature on the structural and morphological, and electrical characteristics of Cu2O nanoparticles synthesized via a coprecipitation method under various temperatures (45°, 55°, 65°, and 75°C). The X-ray diffraction (XRD) analysis indicated a high crystallinity for the fabricated Cu2O nanoparticles with an average crystallite size of approximately (~29 nm), The TEM observations indicate an average particle size of approximately (~50 nm) nanometres. SEM results demonstrated a morphological transition from spherical-cubic to cubic as the aging temperature increased. The electrical properties of the prepared nanoparticles were investigated through AC conductivity and dielectric measurements were taken between 300 K and 550 K temperature range and frequencies ranged from 100 Hz to 5 MHz. Cu2O nanoparticles enhance supercapacitor performance by providing high dielectric constant at low frequencies, improving energy storage, and increasing AC conductivity for efficient charge transport. Their temperature-dependent behaviour and ability to minimize energy losses make them ideal for high-frequency and high-temperature applications. Our findings highlight the exceptional dielectric properties of Cu2O nanoparticles and their remarkable sensitivity to subtle changes in growth temperature. This fine-tuning of the growth conditions allows for the optimization of nanoparticle properties, these characteristics make them suitable candidates for supercapacitor energy applications and other emerging optoelectronic devices.

Highly Stable Electronics Based on β-Ga2O3 for Advanced Memory Applications.

Wide-bandgap (WBG) semiconductors are at the forefront of driving innovations in electronic technology, perpetuating Moore's Law and opening up new avenues for electronic devices. Although β-Ga2O3 has attracted extensive research interest in advanced electronics, its high-temperature and high-speed volatile memory applications in harsh environment has been largely overlooked. Herein, a high-performance hexagonal boron nitride (h-BN)/β-Ga2O3 heterostructure junction field-effect transistor (HJFET) is fabricated, exhibiting an off-state current as low as ≈10 fA, a high on/off current ratio of ≈108, a low contact resistance of 5.6 Ω·mm, and an impressive field-effect electron mobility of 156 cm2 （Vs）-1. Notably, the current h-BN/β-Ga2O3 HJFET exhibits outstanding thermal reliability in the ultra-wide temperature range from 223 to 573 K, as well as long-term environmental stability in air, which confirms its inherent capability of operation in harsh environments. Moreover, the h-BN/β-Ga2O3 HJFET demonstrates successful applications for accelerator-in-memory computing fields, including dynamic random-access memory structure and neural network computations. These superior characteristics position β-Ga₂O₃-based electronics as highly promising for applications in extreme environments, with particular relevance to the automotive, aerospace, and sensor sectors.

Experimental Compressed Liquid Density Measurements and Correlation of the Binary Mixture {n-Pentane (R601) + Trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E))}

Regulations like the F-gas Regulation (EU) 2024/573 and the Kigali Amendment to the Montreal Protocol, along with efforts to mitigate climate change, drive research into alternatives to fluorinated greenhouse gases for high-temperature heat pumps and power generation. Ideal refrigerants should have low GWP, high efficiency, non-flammability, non-toxicity, material compatibility and cost effectiveness. HCFOs have emerged as promising candidates, both as pure fluids and in mixtures with HCs. These blends show efficiency and potential non-flammability for high-temperature applications, but experimental data on their thermophysical properties remain scarce. This study presents the first experimental measurements on the {n-pentane (R601) + trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E))} binary system. In particular, the compressed liquid density of three mixture compositions have been measured employing a vibrating tube densimeter within the temperature range from 283.15 K to 423.15 K and at pressures ranging from 1 MPa to 12 MPa. A novel technique was applied to ensure a combined uncertainty (k=2) not greater than 0.0003 mol·mol-1 in the mixture composition, leading to final combined uncertainty (k=2) on the liquid density of no more than 0.2%. Finally, a new mixture model based on the Helmholtz-energy-explicit Equation of State has been developed from such experimental data. This model accurately represents the behaviour of the binary mixture, enhancing the available understanding of its thermodynamic properties.

Effects of Red Mud on Microstructures and Heat Resistance of ZL109 Aluminum Alloy

The effects of red mud on the microstructures and high-temperature tensile properties of the ZL109 aluminum alloy have been investigated. Red mud/ZL109-based composite materials with added red mud (a major byproduct of the aluminum industry), which has been coated with nickel by chemical deposition, have been prepared through gravity casting. The results show that the addition of red mud promotes the alloy’s microstructure and helps to uniformly distribute the eutectic silicon. It also increases the content of heat-resistant phases, such as the Q-Al5Cu2Mg8Si6 and γ-Al7Cu4Ni phases. These changes significantly enhance the alloy’s high-temperature tensile properties. The alloy with 1% (wt.%) red mud exhibits the best tensile strength at both room temperature and 350 °C, reaching 295.4 MPa and 143.3 MPa, respectively. The alloy with 1.5% (wt.%) red mud demonstrates excellent performance at 400 °C, achieving a tensile strength of 86.2 MPa through the cut-through method and Orowan mechanism. As a reinforcing material, red mud not only improves the high-temperature resistance of the aluminum alloy but also provides a way to recycle industrial waste. This study offers a new way to address the red mud waste problem and helps develop high-performance, heat-resistant aluminum alloys. It shows the potential of these alloys in high-temperature applications.

Microencapsulation of Probiotics for Enhanced Stability and Health Benefits in Dairy Functional Foods: A Focus on Pasta Filata Cheese

Probiotics provide significant health benefits, but their viability is often compromised during production, storage, and passage through the gastrointestinal tract. These challenges hinder their effective incorporation into functional applications, particularly in dairy functional foods, in which factors such as acidity, oxygen exposure, and storage conditions negatively impact cell survival. The focus was on functional dairy foods, particularly on pasta filata cheeses. Indeed, the use of probiotics in pasta filata cheeses presents significant challenges due to the specific manufacturing processes, which encompass the application of high temperatures and other harsh conditions. These factors can adversely affect the viability and availability of probiotic microorganisms. However, microencapsulation has emerged as a promising solution, offering a protective barrier that enhances probiotic stability, improves survival rates, and facilitates targeted release in the gastrointestinal environment. This review examines the pivotal role of microencapsulation in stabilising probiotics for functional applications, emphasising its relevance in high-value food systems. Functional applications, including foods designed to offer essential nutritional benefits and promote host health, play a crucial role in disease prevention and immune system support, reducing the risk of infections and other physiological impairments. Key microencapsulation technologies are analysed, focusing on their benefits, limitations, and challenges related to scalability and industrial implementation. Additionally, this review discusses strategies to optimise formulations, ensure the sensory quality of final products, and explore future opportunities for expanding innovative applications that align with growing consumer demand for health-promoting solutions.

Thermally stable PSA film with reduced adhesion after thermal and UV treatment

Acrylic pressure-sensitive adhesives (PSAs), commonly used for their low glass transition temperature (Tg), often exhibit poor heat resistance. This poses challenges in high-temperature applications in semiconductor processing and enhancing the heat resistance of PSAs has been achieved through chemical crosslinking. In this study, PSAs were developed that maintains adhesion during thermal treatment and reduces adhesion after photo treatment, allowing easy separation from silicon wafers. The PSAs was synthesized by copolymerization of 2-ethylhexyl acrylate (2-EHA), acrylonitrile (AN), and 4-hydroxybutyl acrylate (4-HBA) with final composition ratios of 72.6, 12.3, and 15.1 mol% respectively. Hexamethylene diisocyanate (HDI) and 2-isocyanatoethyl methacrylate (MOI) were attached to the hydroxyl group of 4-HBA to control the degree of crosslinking. Corona-treated polyethylene naphthalate (PEN) was used as a base film, which was suitable for processing at high-temperatures of approximately 250 °C. The peel strength of PSAs decreased from 9.64 N/in. to 6.75 N/in. after thermal treatment. This decrease is attributed to increased crosslinking density through AN cyclization during the thermal treatment unlike conventional PSA which is inseparable after thermal treatment. After photo treatment, peel strength decreased from 6.75 N/in. to 3.62 N/in., indicating additional crosslinking due to intermolecular reactions of the methacrylate groups in MOI. The increase in crosslinking density was verified through gel fraction analysis, which showed a rise from 65.2 %, as prepared, up to 97.6 % after thermal and photo treatment. Trimethylolpropane triacrylate (TMPTA) was used to form additionally crosslinked networks during photo treatment. The final gel fraction increased with the TMPTA content, rising from 97.6 % without TMPTA to 99.1 % with 20 wt% TMPTA. The peel strength also decreased down to 1.50 N/in. with 20 wt% TMPTA with only 0.85 % residue. These results provide valuable insights for engineering PSAs with controlled adhesion characteristics, thereby enabling the development of advanced PSAs suited for semiconductor industry applications.

Effectiveness-MTU modeling approach for hydrogen separation with dense metallic membranes

As hydrogen gains interest as energy vector, so it happens for its purification techniques. In particular, dense metallic membranes are a promising technology for many high-temperature applications. Modeling of hydrogen permeation is a fundamental support to their commercial development. Permeation through metallic membranes, in particular Pd-alloys, is regulated by a generalized form of the Richarson’s equation, where driving force for permeation is due to the difference in hydrogen partial pressure at the membrane surfaces. From the flux expression it is possible to develop a model for a mass exchanger, in analogy with the mathematical description of heat exchangers. For the latter, a well-known method, called , is used to simplify heat transfer problem. The same approach applies to mass exchangers, where the method had already been transferred to reverse osmosis. In this article, method is applied to ideal mass exchangers for hydrogen separation. Effectiveness showed to be influenced by inlet hydrogen fraction, exponent of partial pressures and pressure ratio. Moreover, a procedure to include concentration polarization losses is presented. A rule-of-thumb approach is proposed for an estimation of hydrogen recovery, validated to reproduced an experimental result with less that 7% relative error. shows to be a fundamental support to membrane module design.

Chemical short-range order and its influence on selected properties of non-dilute random alloys

In recent years, non-dilute random alloys (NDRAs) have been gaining interest as promising materials for high-temperature structural applications due to their unique ability to form solid solution phases that portray exceptional mechanical properties and resilience under extreme conditions. This study deals with the effects of chemical short-range order (CSRO) on selected material properties including lattice parameters, lattice distortion (LD), unstable stacking fault energy (USFE), and melting points (MPs). The main body of this study is on 21 ternary alloys, where the interatomic interactions are described by an embedded-atom method potential. Our results demonstrate that random structures generally exhibit larger lattice parameters and greater LD compared to CSRO structures, while CSRO structures possess higher USFEs and MPs. Furthermore, there is no discernible pattern in the segregation of the same and different atom pairs in the NDRAs, as revealed by the notably varying local ordering or segregation for most of them. Last, the effects of interatomic potential and the number of constituent elements are studied using other interatomic potentials and/or non-ternary systems, suggesting that our finding is consistent across different potentials/alloys.

High-strength polyurethane-reinforced glass fiber spacer fabric for cost-effective, lightweight, and high-temperature insulation applications

High-strength polyurethane-reinforced glass fiber spacer fabric for cost-effective, lightweight, and high-temperature insulation applications

Design, fabrication, and thermal zero drift compensation of a SOI pressure sensor for high temperature applications

Design, fabrication, and thermal zero drift compensation of a SOI pressure sensor for high temperature applications

Effects of Temperature and Bimodal Microstructure on the Mechanical Properties and Fracture Mechanisms of High-Strength Al-Ni-Cu-Fe Alloy Fabricated through Laser Powder Bed Fusion

This study investigates the mechanical properties of an Al-Ni-Cu-Fe alloy fabricated using laser powder bed fusion (LPBF) technology, evaluated at temperatures ranging from room temperature to 300°C under various strain rates for potential aerospace and automotive applications. Aluminum alloys often face the challenges of maintaining high-temperature strength and stability, limiting their use in demanding environments. The results demonstrate that the LPBF Al-Ni-Cu-Fe alloy maintains strength above 300 MPa at standard strain rates and reaches up to 400 MPa at high strain rates at 300°C, indicating its suitability for lightweight, high-strength vehicles and thermal engineering systems. The high-temperature strengthening mechanisms are attributed to Al9FeNi submicron cellular eutectic walls that impede dislocation motion and precipitation strengthening from Al2Cu. Fracture analysis reveals that localized brittleness limits elongation to 3% at room temperature, with deformation distributed between coarse-grained (CG) and fine-grained (FG) regions. At elevated temperatures (300°C), partial homogenization of FG regions reduces melt pool constraints, promoting local deformation. Therefore, ductility increases significantly under high strain rates as the dispersed Al9FeNi phases become less effective in resisting instantaneous stresses, allowing deformation to overcome melt pool boundaries. At extreme strain rates during impact testing, twinning becomes the dominant deformation mechanism, contrasting with tensile testing. These findings confirm the potential of the LPBF Al-Ni-Cu-Fe alloy as a heat-resistant printed aluminum alloy for high-temperature applications and provide valuable insights into fracture mechanisms within the bimodal microstructure, guiding future alloy optimization.

Nano-Grafted Polymer Suspension Stabilizers for Oil Well Cement: Polymerization Innovation Dominated by Acrylamide and Breakthroughs in High-Temperature Applications

Nano-Grafted Polymer Suspension Stabilizers for Oil Well Cement: Polymerization Innovation Dominated by Acrylamide and Breakthroughs in High-Temperature Applications

Thermal characterization, modeling and parametric model order reduction (PMOR) of piezoelectric transducers

Abstract The consideration of the thermals of piezoelectric transducers has gained relevance due to the increasing demands on the performance of actuators as well as the special applications such as high-power, high-precision or high-temperature applications. In the state of the art, many works deal with the representation of the temperature-dependence of piezoelectric performance and the development of suitable systems that are optimized in terms of self-heating. The prerequisite for this, is to characterize the actuators thermally and to have thermal models of piezoelectric actuators, that represent the temperature of the actuator. In this paper a workflow is presented for the thermal characterization and modeling of piezoelectric transducers in a fast and non-destructive manner. Aim of this work is to generate Finite-Element (FE) Models and Reduced Order Models (ROM) of the thermal behaviour of piezoelectric transducers for many different sizes of actuators. For this purpose an experimental setup and characterization workflow are developed. The advantage of the workflow lies in the speed of characterization through direct comparison of measurement results with a Metamodel and automated model order reduction. Parametric model order reduction (PMOR) is also investigated in this context for faster model building and compared to the results of FE and ROM. Model order reduction offers the advantage that the resulting models are low in computing effort, can be used without FE software and can directly be included in for example control or system models. Finally by direct comparison with a simple circuit model as in the state of the art the advantages of FE modeling can be shown. The workflow can be used for many different test specimen that vary in size and shape. The method is exemplarily presented using a Lead Zirconate Titanate (PZT) multilayer actuator.

Numerical Design and Optimization of High Performance Langasite and Hetero-Acoustic Layer-Based Surface Acoustic Wave Device

La3Ga5SiO14 (langasite, LGS)-based surface acoustic wave (SAW) devices are widely used for industrial health monitoring in harsh high-temperature environments. However, a conventional LGS-based SAW structure has a low quality factor (Q) due to its spurious resonant peaks. A hetero-acoustic layer (HAL)-based structure can effectively enhance the Q factor and the figure of merit (FOM) of SAWs due to its better energy confinement of SAWs. In this work, a HAL-based structure is proposed to achieve a high FOM and high-temperature resistance at the same time. Based on the finite element method (FEM) and coupling-of-model (COM) combined simulation, a systematic numerical investigation was conducted to find the optimal materials and structural parameters considering the viability of an actual fabricating process. After optimizing the layer number, an intermediate-layer material choice and structural parameters, Pt/(0°, 138.5°, 27°) LGS/YX-LGS/SiC HAL structure were chosen. The proposed structure achieves a Q factor and FOM improvement of more than 5 and 2.6 times higher than those of conventional SAW structures, which is important for the development of high temperature SAW sensors. These findings pave a viable method for improving the Q factor and FOM of LGS-based SAW and can provide material and device structural design guidance for fabrication and high-temperature applications in the future.