Quantum dots (QDs) have sparked great interest due to their unique electronic, optical, and structural properties. In this review, we provide a critical analysis of the latest advances in the synthesis, properties, and applications of QDs. We discuss synthesis techniques, including colloidal and hydrothermal synthesis, and highlight how the underlying principles of these techniques affect the resulting properties of QDs. We then delve into the wide range of applications of QDs, from QDs based color conversion, light-emitting diodes and biomedicine to quantum-based cryptography and spintronics. Finally, we identify the current challenges and future prospects for quantum dot research. By reading this review, readers will gain a deeper understanding of the current state-of-the-art in QDs research and the potential for future development.
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Kushagra Agarwal et al 2023 Mater. Res. Express 10 062001
William Xaveriano Waresindo et al 2023 Mater. Res. Express 10 024003
Hydrogel is being broadly studied due to their tremendous properties, such as swelling behavior and biocompatibility. Numerous review articles have discussed hydrogel polymer types, hydrogel synthesis methods, hydrogel properties, and hydrogel applications. Hydrogel can be synthesized by physical and chemical cross-linking methods. One type of the physical cross-linking method is freeze-thaw (F–T), which works based on the crystallization process of the precursor solution to form a physical cross-link. To date, there has been no review paper which discusses the F–T technique specifically and comprehensively. Most of the previous review articles that exposed the hydrogel synthesis method usually mentioned the F–T process as a small part of the physical cross-linking method. This review attempts to discuss the F–T hydrogel specifically and comprehensively. In more detail, this review covers the basic principles of hydrogel formation in an F–T way, the parameters that influence hydrogel formation, the properties of the hydrogel, and its application in the biomedical field.
Ahmad Y Al-Maharma et al 2020 Mater. Res. Express 7 122001
In the present review, the effect of porosity on the mechanical properties of the fabricated parts, which are additively manufactured by powder bed fusion and filament extrusion-based technologies, are discussed in detail. Usually, additive manufacturing (AM) processes based on these techniques produce the components with a significant amount of pores. The porosity in these parts typically takes two forms: pores with irregular shapes (called keyholes) and uniform (spherical) pores. These pores are present at different locations, such as surface, sub-surface, interior bulk material, between the deposited layers and at filler/matrix interface, which critically affect the corrosion resistance, fatigue strength, stiffness, mechanical strength, and fracture toughness properties, respectively. Therefore, it is essential to study and understand the influence of pores on the mechanical properties of AM fabricated parts. The technologies of AM can be employed in the manufacturing of components with the desired porous structure through the topology optimization process of scaffolds and lattices to improve their toughness under a specific load. The undesirable effect of pores can be eliminated by using defects-free raw materials, optimizing the processing parameters, and implementing suitable post-processing treatment. The current review grants a more comprehensive understanding of the effect of porous defects on mechanical performance and provides a mechanistic basis for reliable applications of additively manufactured components.
Noorah A Al-Ahmadi 2020 Mater. Res. Express 7 032001
Metal-oxide-semiconductor (MOS) structures are essential for a wide range of semiconductor devices. This study reviews the development of MOS Schottky diode, which offers enhanced performance when compared with conventional metal-semiconductor Schottky diode structures because of the presence of the oxide layer. This layer increases Schottky barrier heights and reduced leakage currents. It also compared the MOS and metal-semiconductor structures. Recent advances in the development of MOS Schottky diodes are then discussed, with a focus on aspects such as insulating materials development, doping effects, and manufacturing technologies, along with potential device applications ranging from hydrogen gas sensors to photodetectors. Device structures, including oxide semiconductor thin film-based devices, p-type and n-type oxide semiconductor materials, and the optical and electrical properties of these materials are then discussed with a view toward optoelectronic applications. Finally, potential future development directions are outlined, including the use of thin-film nanostructures and high-k dielectric materials, and the application of graphene as a Schottky barrier material.
Zhang Chao et al 2024 Mater. Res. Express 11 085802
As a carbon-free hydrogen-rich energy carrier, ammonia has gained increasing attention and application in the context of carbon peaking and carbon neutrality. This study evaluated the stress corrosion cracking (SCC) sensitivity of four target materials, A516-70, 16MnDR, 15MnNiDR, and Q370DR, in a liquid ammonia environment at 25 °C and 1.03 MPa by slow stress rate tests to determine their SCC sensitivity index. The microstructure, grain size, misorientation, hardness, strength, and micro-fracture morphology of these materials were compared to analyze the SCC mechanism. The results showed that 15MnNiDR exhibited significant SCC sensitivity while both 16MnDR and A516-70 demonstrated certain levels of SCC sensitivity in liquid ammonia. However, Q370DR showed no SCC sensitivity under these conditions. The misorientations observed align with the strains experienced by each respective carbon steel in liquid ammonia. An unstable passivation film formed on the surface of 15MnNiDR steel when exposed to liquid ammonia whereas Q370DR developed a stable oxide film which contributed to its weak SCC sensitivity.
Yangang Li et al 2022 Mater. Res. Express 9 122001
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted extensive attraction due to their unique properties in novel physical phenomena, such as superconductors, Moiré superlattices, ferromagnetics, Weyl semimetals, which all require the high quality of 2D TMDs. Mechanical exfoliation (ME) as a top-down strategy shows great potential to obtain 2D TMDs with high quality and large scale. This paper reviews the theoretical and experimental details of this method. Subsequently, diverse modified ME methods are introduced. Significantly, the recent progress of the Au-assisted ME method is the highlight. Finally, this review will have an insight into their advantages and limitations, and point out a rational direction for the exfoliation of TMDs with high quality and large size.
Aditi Chopra et al 2024 Mater. Res. Express 11 085009
One of the fundamental challenges of working with surface plasmon resonance (SPR) biosensors is their inherent lack of specificity. Being very sensitive to minute refractive index (RI) changes in their surrounding medium, SPR biosensors are highly susceptible to variations in pH, temperature, and buffer composition. Therefore, it is often necessary to include an additional validation step downstream to SPR biosensing, particularly for clinical analysis. In this proof-of-study work, we have tried to evaluate the utility of surface-enhanced Raman scattering (SERS) tags as secondary labels for validating SPR biosensor response. Accordingly, a Fibre-optic SPR (FO-SPR) biosensor set-up was fabricated by immobilizing anti-BSA antibodies on the sensor platform for capturing and sensing biotinylated-BSA as a model analyte. Subsequently, the bound analyte and the concomitant shift in SPR response were validated by employing streptavidin-functionalized SERS tags. Intriguingly, apart from validation of the SPR response, the SERS tags also significantly improved the sensitivity of the SPR response and provided semi-quantitative information on the bound analyte. Although utilizing SERS tags undermines the label-free tag of SPR biosensors, the huge improvement in sensitivity and specificity of the sensor makes it suitable for clinical analysis. Furthermore, SERS measurements with a portable Raman spectrometer utilized in this study further highlight the potential of this approach for achieving point-of-care (POC) sensing.
Souvik Banerjee et al 2024 Mater. Res. Express 11 106103
We report the high-temperature magnetic ordering and the observation of linear negative magnetocapacitance mediated by a low-temperature magnetic phase crossover in the compound LiFe2SbO6. The combined observations of the absence of a second harmonic generation (SHG) signal, and Rietveld refinements of x-ray and neutron powder diffraction (NPD) patterns of the sample confirm that LiFe2SbO6 crystalizes in a centrosymmetric Pnnm structure. The DC magnetization measurements reveal that an antiferromagnetic ordering sets in at high temperature (TN = 850). The magnetic anomaly in the DC magnetization at a lower temperature T = 13 K, is corroborated by AC susceptibility and the specific heat measurements. In association with this magnetic phase crossover, a linear negative magnetocapacitance was observed below this temperature. Further, the neutron powder diffraction study reveals a collinear antiferromagnetic ordering with a wavevector k = (0, 0, 0).
Xi Huang et al 2020 Mater. Res. Express 7 066517
The oxidation behavior of 316L stainless steel exposed at 400, 600 and 800 °C air for 100, 500 and 1000 h was investigated using different characterization techniques. Weight gain obeys a parabolic law, but the degree of deviation of n index is increasingly larger with the increase of temperature. A double oxide film, including Cr2O3 and Fe2O3 oxide particles in outer and FeCr2O4 oxides in inner, is observed at 400 °C. As regards to samples at 600 °C, a critical exposure period around 100 h exists in the oxidation process, at which a compact oxide film decorated with oxide particles transforms to a loose oxide layer with a pore-structure. In addition, an oxide film containing Fe-rich outer oxide layer and Cr-rich inner oxide layer is observed at 600 °C for 500 and 1000 h. Spallation of oxide scale is observed for all samples at 800 °C regardless of exposure periods, resulting in different oxidation morphologies, and the degree of spallation behavior is getting worse. A double oxide film with the same chemical composition as 600 °C is observed, and the thickness increases over exposure periods.
Mir Waqas Alam et al 2024 Mater. Res. Express 11 102001
In order to meet the demand for portable water and replenish depleting water resources caused by industrialization, urbanization, and population growth; wastewater purification has become crucial. Emerging contaminants (ECs), which include organic dyes, pesticides, pharmaceutical drugs, polyaromatic compounds, heavy metal ions, and fertilizers, among others, have caused significant disruptions to environmental balance and severe health complications. As a result, considerable effort has been devoted to the development of technologies that eliminate wastewater from effluents via adsorption, photocatalysis, and other means. However, considering the economic and environmental implications of the adopted technologies, green technology has gained significant attention owing to their eco-friendly approaches, cost-effectiveness, avoiding use of toxic and harmful chemicals and production of less-toxic by-products. Currently green-synthesized nanomaterials have seen tremendous growth in emerging as sustainable nanoadsorbents, nanocatalysts for the removal of the emerging contaminants from wastewater in highly efficient and eco-friendly manner. Thus, this review presents an overview of the various techniques utilized in wastewater treatment with a particular emphasis on the production and application of environmentally friendly transition metal/metal oxide nanoparticles as sustainable tools in wastewater treatment technology. This article also discusses the limitations and future potential of using green-synthesized transition metal/metal oxide based nanoparticles in advancing the technology on a broad scale.
Qianqian Zhang and Li Cao 2024 Mater. Res. Express 11 116515
The anode foil is a critical component of aluminium electrolytic capacitors, with its performance directly impacting the overall quality of the capacitors. Currently, sintered anode foil with excellent bending resistance and high specific capacitance is considered an ideal material for capacitor manufacturing; however, research on its optimal sintering parameters remains insufficient. In this study, a three-dimensional temperature field model is developed within the Comsol Multiphysics (6.0) environment, accounting for the temperature dependence of aluminium. By varying laser power and scanning speed, the temperature distribution along the laser scanning trajectory is determined, facilitating the identification of optimal process parameters for laser sintering anode foils in electrolytic capacitors. Subsequent laser sintering experiments validate the accuracy of these parameters. The findings indicate that the peak temperature of the molten pool rises with increased laser power and decreased scanning speed. The optimal process parameters for laser sintering anode foils in electrolytic capacitors are a powder layer thickness of 50 μm, a laser power of 140 W, and a scanning speed of 0.05 m s−1. The specific capacitance of laser-sintered anode foil, formed at voltages of 375 V and 520 V, ranges from 0.847 to 1.157 μF cm−2 and 0.717 to 0.935 μF cm−2, respectively, when the particle size is between 3 and 4 μm. A specific capacitance of 0.733 μF cm−2 can be achieved, which meets the performance requirements for aluminium electrolytic capacitors.
Dieter Rahmadiawan et al 2024 Mater. Res. Express 11 115302
This study investigates the synergistic effects of incorporating layered double hydroxide (LDH) and tannic acid (TA) into polyvinyl alcohol (PVA) films to enhance their mechanical, tribological, and corrosion resistance properties for biomedical applications. Composite coating films were prepared by blending PVA with LDH and TA in various concentrations. The addition of LDH and TA significantly increased the crystallinity index of the composite films, with the highest crystallinity observed at 66.3% for the sample containing 1 wt% TA and 2 wt% LDH (PVA/TA1/LDH2). This enhancement in crystallinity contributed to improved mechanical performance, as demonstrated by tensile tests, where the PVA/TA1/LDH2 composite exhibited the highest tensile strength among all samples. Tribological testing revealed that the PVA/TA1/LDH2 composite also achieved the lowest coefficient of friction (COF), along with a minimal wear rate, indicating superior wear resistance. SEM analysis of the wear scars confirmed a narrow wear track and smoother surface morphology for this composite, which suggests effective load distribution and reduced surface degradation. The addition of TA was further shown to improve the corrosion resistance of the PVA composite films, with the PVA/TA1/LDH1 sample exhibiting the lowest corrosion current density (Icorr) of 0.36 μA cm−2, representing a significant improvement over neat PVA. These findings highlight the potential of PVA/LDH/TA films for coating applications in biomedical devices, where enhanced mechanical strength, wear resistance, and corrosion protection are critical. The synergistic effects of LDH and TA provide a pathway for developing durable and functional coatings, expanding the practical utility of PVA films in demanding biomedical environments.
Orhan Gülcan et al 2024 Mater. Res. Express 11 116514
This experimental study focuses on the effect of overhang and recoater angles on the surface roughness of overhang specimens produced by laser powder bed fusion (LPBF) process from CoCr material and by using contactless support structures. The inclination of overhang surface with respect to build platform and the orientation of the specimens with respect to recoater direction were selected as design inputs and the average and the maximum surface roughness of overhang surfaces were selected as design outputs. Experimental studies revealed that decreasing overhang angle increased the surface roughness. 90-degree orientation of the part with respect to recoater direction resulted in minimum average surface roughness. It was also observed that contactless support didn't give enough structural strength to 20-degree overhang surface which failed to be manufactured. Thermomechanical modelling-based process simulations were also performed, and very good correlation was found between numerical and experimental results. It was shown that thermomechanical modelling is very useful to be performed before LPBF process to mitigate recoater jam risks.
Aravindhan Vanangamudi and Sathyanarayanan Punniyakoti 2024 Mater. Res. Express 11 116402
Fouling is a major issue occurring in water-going vessels, such as ships that cause increased surface roughness and drag resistance. The fouling organisms produce extracellular polymeric substances (EPS), which negatively impact water-going vessels. The settlement-inducing protein complex (SIPC) is a contact pheromone that promotes the gregarious settling of barnacle larvae (cyprids). The SIPC can be found in both adult barnacle cuticles and cyprids as transient adhesive secretions (footprints). The presence of SIPC in the footprints plays a critical role during the initial adhesion, which facilitates further settlement. The adsorption of of SIPC on Iron/Fe ship strip(FSS) surface was often found to be irreversible even after physical treatements. For the antifouling studies, Nb2O5 coated FSS were constructed and simulated to analyze the interaction of barnacles Aacp20K protein. For simulation studies, the homology model of barnacles Aacp20K protein is fabricated using the SWISS automated comparative modeling platform. The result of homology model showed a good 3D secondary structure of Aacp20K protein, especially 7q1y template protein. Adsorption location analysis results illustrate that the surface of the FSS coated with Nb2O5 film disfavour the binding of SIPC inhibiting the binding of barnacle cuticles and cyprids. For validating the simulation results, Nb2O5 nanostructure film was synthesized using a solvothermal process and characterized using XRD,SEM and EDS. Furthermore, the wetting behaviour was studied experimentally. The simulations and experimental results indicate Nb2O5-coated FSS as potent anti-fouling surfaces.
Yaxin Ma et al 2024 Mater. Res. Express 11 116513
This study explores the relationship between the microstructure, composition, orientation, and mechanical properties of the nickel-based superalloy Inconel 718. Employing scanning electron microscopy (SEM), electron microprobe (EMP), nano-indentation, and other techniques, the study observes the structure, confirms the composition, determines orientation, and tests mechanical properties in specific micro-zones. Findings reveal a uniform grain distribution in Inconel 718, with a minor δ-phase presence at grain boundaries. There is a notable enrichment of Nb at the grain boundaries, whereas Fe and Cr levels are lower at these boundaries compared to the grain interiors. The indentation hardness and modulus at the grain boundaries are markedly higher than those within the grains. Moreover, grains with different orientations exhibit diverse microscale mechanical properties, such as hardness and elastic modulus. This research establishes a quantitative characterization and mapping relationship between the microstructure, composition, orientation, and mechanical properties of Inconel 718, providing a foundation for future multiscale (micro to macro) mechanical property investigations.
Hao Gu 2024 Mater. Res. Express 11 112001
Although rigid transducers have led to innovations in industrial automation and control systems, their rigidity limits them to the controlled environment of the factory. Recently, soft transducers have become an attractive area of research because their compliant nature has the potential to be applied to soft-bodied robots that operate in uncontrolled environments. Dielectric elastomer transducers (DETs) demonstrate large electrically-driven deformations, high energy density, fast response, long lifespans, and self-healing capabilities, making them a favorable replacement for rigid transducers. This review first introduces the working principles of DETs, modeling work, and DET configurations. Subsequently, the applications of DETs in robotics, generators, sensors, and electronics are reviewed. Finally, the challenges currently faced by DET technology are discussed and potential approaches are explored.
Mir Waqas Alam et al 2024 Mater. Res. Express 11 102001
In order to meet the demand for portable water and replenish depleting water resources caused by industrialization, urbanization, and population growth; wastewater purification has become crucial. Emerging contaminants (ECs), which include organic dyes, pesticides, pharmaceutical drugs, polyaromatic compounds, heavy metal ions, and fertilizers, among others, have caused significant disruptions to environmental balance and severe health complications. As a result, considerable effort has been devoted to the development of technologies that eliminate wastewater from effluents via adsorption, photocatalysis, and other means. However, considering the economic and environmental implications of the adopted technologies, green technology has gained significant attention owing to their eco-friendly approaches, cost-effectiveness, avoiding use of toxic and harmful chemicals and production of less-toxic by-products. Currently green-synthesized nanomaterials have seen tremendous growth in emerging as sustainable nanoadsorbents, nanocatalysts for the removal of the emerging contaminants from wastewater in highly efficient and eco-friendly manner. Thus, this review presents an overview of the various techniques utilized in wastewater treatment with a particular emphasis on the production and application of environmentally friendly transition metal/metal oxide nanoparticles as sustainable tools in wastewater treatment technology. This article also discusses the limitations and future potential of using green-synthesized transition metal/metal oxide based nanoparticles in advancing the technology on a broad scale.
Nana Zhang 2024 Mater. Res. Express 11 092001
Rare earth light conversion agent material is a fluorescent material that can convert solar energy into light of different wavelengths for various applications. In this paper, the research progress of organic rare earth complexes and inorganic rare earth light conversion agent materials is first reviewed. Then, the luminescence principles, classification, synthesis methods, characterization and performance methods of organic rare-earth complexes and inorganic rare-earth light conversion agent materials are reviewed, as well as their recent progress in agricultural film applications. Finally, the challenges and development prospects faced by organic rare earth complexes and inorganic rare earth light conversion agent materials are summarized.
Soumyadeep Sur et al 2024 Mater. Res. Express 11 072003
Multicomponent systems were proposed in 2004 with tremendous potential in various applications. The central idea was to enhance the configurational contribution to entropy of a (nearly) equiatomic mixture of element to achieve invariability. In 2015, this concept of entropy induced stabilization was illustrated in a blend of oxides. Following this, other entropy stabilized oxides were studied, exploding in the vast composition space with materials showing enhanced properties. These systems were adept in wide range of technologies ranging from thermal barrier coatings, ultra-high temperature refractories, wear and corrosion resistant coatings, catalysts, thermoelectrics, and electrochemical energy storage systems (EES). We will walk through the recent developments in high entropy oxides for reversible energy storage in this review, looking at the high entropy attributes that enhance their electrochemical capabilities. The influence of entropy can no longer be avoided in ceramics and will be crucial to the advancement of sustainable technologies in the future.
Divya Prakash Dubey and Ratnamala Chatterjee 2024 Mater. Res. Express 11 072002
In recent years, research on thermoelectric materials has garnered considerable attention, owing to their potential to offer efficient and environmentally friendly energy solutions. Metal oxides have emerged as strong contenders for thermoelectric materials, offering a promising avenue for implementing diverse mechanisms aimed at achieving higher thermoelectric efficiency. In this review, we investigate the influence of magnetic fields on the thermoelectric properties of oxide-based materials. Drawing insights from existing literature, we provide a comprehensive overview of how magnetically tuned Seebeck coefficients, thermal conductivity, and electrical resistivity impact the thermoelectric performance of oxide-based thermoelectrics. Literature available on magnetic field tuning of Spin Seebeck effect and anomalous Nernst effect for improved efficiency in oxide-based systems, have also been included in this review.
Hu et al
With the continuous improvement of voltage level, power level and capacity level of high-voltage transmission and substation equipment, the problem of power loss and equipment failure caused by abnormal heating of electrical contact parts is becoming increasingly serious. To address this problem, graphite was exfoliated into thin layers of graphene by liquid-phase mechanical exfo-liation, ultrasonic dispersion and spray-drying techniques, and it was incorporated into polyether composites to enhance its electrical conductivity. The effect of graphene content on the electrical conductivity, high temperature resistance, wear reduction and anti-wear properties of polyether composites was investigated. The results indicated that when graphene is added at 4 wt%, the high-temperature resistance of the graphene-polyether composite (GPC) is improved to 330 °C, and the volume resistivity is reduced to 6.5×103 Ω-cm. Moreover, the contact resistance coefficient of the GPC is reduced to 0.87 and 0.73 after it is coated on the Cu rows and the Al rows, respectively, which effectively enhances the electrical conductivity of the electrical contact area. In addition, the best improvement in friction reduction and anti-wear properties was obtained for the polyether composites from this formulation. Above all, the GPC has excellent electrical conductivity, high-temperature resistance, wear reduction and anti-wear properties, which can substantially improve the quality of the electrical connection when applied to the electrical contact tips.
Alamry et al
Natural fiber-reinforced hybrid bio-composites are emerging as sustainable alternatives to traditional composites due to their environmental benefits and desirable properties. However, the interfacial interaction between natural fiber and polymer matrix is very weak. Thus, this study looks into the effect of maleic anhydride (MAH) coupling agents on the performance of natural fiber-reinforced hybrid biocomposites. The bio-composites were prepared using jute fiber, kenaf fiber, and polylactic acid (PLA) through the hot compression method. We treated both natural fibers with MAH coupling agents before using them in the production of biocomposites. Comprehensive characterization techniques, including tensile strength, modulus, and impact strength, were employed to evaluate the mechanical properties of the composites. The mechanical results indicated a significant improvement in mechanical properties for the bio-composites treated with coupling agents. The tensile strength of bio-composites increased by 35%, tensile modulus by 15%, and impact strength by 20% after modification with MAH coupling agents. The surface morphology and chemical interactions between the fiber and polymer matrix were investigated using SEM and FTIR studies. The FTIR result reveled that the intensity of C=O peaks enhanced after MAH treatment. Moreover, SEM images exposed better fiber dispersion and adhesion, corroborated by FTIR spectra showing enhanced chemical bonding where MAH reacted with the cellulose backbone of the fibers and formed fiber cellulose ester. Furthermore, TGA results revealed that adding MAH coupling agent to the fiber increased the thermal stability of biocomposites.
Ren et al
This paper examines the influence of modification methods and the content of attapulgite (ATP) on the flame retardancy of polybutylene terephthalate (PBT). Different samples of ATP with varying modification methods and contents were blended with PBT to create composites. The composition, stability, flame retardancy, and mechanical properties of the composites were analyzed. The effect mechanism of ATP modification methods and content on the flame retardancy of PBT was analyzed. The results indicate that the addition of ATP enhanced the carbonization and flame retardancy of PBT. The addition of ATP reduced the impact strength of PBT. The inclusion of ball milled modified attapulgite (mp-ATP) resulted in an increase in the tensile strength of PBT. Furthermore, the inclusion of mp-ATP led to a mitigated decrease in the impact strength. The composites with 11%mp-ATP/PBT had the best comprehensive performance. Compared with pure PBT, the peak value of thermal release rate decreased by 70.2%, the total heat release decreased by 27.3%, and the tensile strength increased by 2.9%.
Hou et al
Sound absorbing materials are widely used in the field of automotive industry. Biomass materials are abundant in nature, and some biomass has natural sound absorption and noise reduction properties. Biomass sound absorption material is green and pollution-free, and has obvious noise reduction effect on middle and high frequency noise, large specific surface area, light weight, and strong sound absorption effect. In order to analyze the sound absorption and physical properties of biomass sound absorbing materials, the noise reduction performance of the different structure of biomass sound absorbing materials were analyzed. In this paper, the biomass sound absorbing materials coconut fiber and coconut shell activated carbon particles were used to make samples. Coconut shell activated carbon sound absorption material (CSAC) was made. The cylindrical holes was made and filled with coconut fiber materials to form composite sound absorbing materials (CSAC-F). The acoustic performance of impedance tube was tested based on the acoustic absorption coefficient, and the physical performance was studied by means of Scanning Electron Microscope (SEM), Brunauer, Emmett and Teller (BET), X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetric (TGA) and other detection methods. In contrast, the sound absorption effect of CSAC-F was better in the middle and low frequency range. The microstructure of the material was analyzed and the mechanism of noise reduction was studied. This research will provide a new way for the research and development of sound absorbing materials in the automotive industry, and biomass sound absorbing materials have potential applications in the noise absorption and vibration control of automotive interior.
Szabó et al
In this research, the failures and possible solutions of direct metal laser sintering (DMLS) have been investigated, with the aim of presenting an overview of the current state of science and possible technical solutions to the various challenges and potential solutions. DMLS technology allows to produce high density parts and has proven to be suitable for the cost-effective production of both mass-produced and individual parts in the automotive, aerospace, medical and hydrogen technology industries. This study reveals the fundamental principles, potential benefits, and limitations of metal 3D printing. The defects are categorized into those related to raw materials and those caused by the manufacturing process. The properties of the parts fabricated by this method are mainly depending on the quality of the raw material and the intensity of the laser beam. Clusters of raw materials have a negative impact on the whole manufacturing process, requiring their investigation and avoidance. Another critical defect identified is the significant internal stress generated during the manufacturing process. Various methods are developed to quantify and mitigate these internal stresses. This study provides a detailed analysis of these defects and their impacts, along with a review of literature-based solutions. Among the evaluated and implemented solutions, emphasis is placed on the effects of preheating the build plate and post-process heat treatment. Future objectives and research directions are proposed, presenting and assessing alternative solutions such as Vibratory Stress Relief (VSR) and Thermo-Vibratory Stress Relief (TVSR), which combine heat treatment with vibration. In the scope of the research, the process by which the most common failures occur, and their potential outcomes was reviewed. Special attention was given to deformation caused by internal stress and the possibilities for its mitigation. The feasibility of applying a new approach was investigated, and future research objectives were outlined. SEM imaging was employed to conduct and analyse the grain size of stainless-steel raw material, and agglomerates were observed in the post-print recycled powder.