Matrix Phase Research Articles

Protein Cage-like Vesicles Fabricated via Polymerization-Induced Microphase Separation of Amphiphilic Diblock Copolymers

Highly symmetric protein cages represent one of the most artistic architectures formed by biomolecules. However, the underlying reasons for the formation of some of these architectures remain unknown. The present study aims to investigate the significance behind their morphological formation by fabricating protein cage-like vesicles using a synthetic polymer. The vesicles were synthesized by combining polymerization-induced self-assembly (PISA) with polymerization-induced microphase separation (PIMS), employing an amphiphilic poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-cyclohexyl methacrylate-random-methacrylic acid) diblock copolymer, PMAA-b-P(BMA-r-CMA-r-MAA). The copolymer, with a 60 mol% molar ratio of CMA to the BMA units, produced clathrin-like vesicles with angular windows in their shell, resulting from the segregation of the hard CMA units from the soft BMA matrix in the hydrophobic phase of the vesicle. These vesicles were highly stable against rising temperatures. In contrast, the vesicles with a 30 mol% CMA ratio dissociated upon heating to 50 °C into triskelion-like segments due to intramolecular microphase separation. These findings indicate that designing synthetic polymers can mimic living organ morphologies, aiding in elucidating their morphological significance and inspiring the development of new materials utilizing these morphologies.

In situ experimental investigation of fiber orientation kinetics and rheology of polymer composites in shear flow

In this study, we experimentally investigate the fiber orientation kinetics and rheology of fiber-filled polymer melts in shear flow. A novel setup is designed with custom-built bottom and top geometries that are mounted on a conventional rotational rheometer. Shear flow between parallel sliding plates is applied by vertical movement of the top geometry. The axial force measurement data of the rotational rheometer are used to determine the shear stress growth coefficient. The fiber orientation kinetics are measured in situ with this setup using small angle light scattering. We consider a non-Brownian experimental system with short glass fibers for the suspended phase (L/D=8–15) and different polyethylene based materials for the matrix phase. The fiber orientation kinetics are investigated as a function of fiber volume fraction (ϕ=1%, 5%, and 10%) and as a function of the shear rate (γ˙=0.03, 0.55, and 5s−1). Within the studied range, these parameters do not influence the fiber orientation kinetics, and a multiparticle model, based on Jeffery’s equation for single particles, can describe these kinetics. Our results show that, up to the concentrated regime (ϕ≈D/L), fiber-fiber interactions do not influence the fiber orientation in shear flow. Finally, we investigate the shear stress growth coefficient of these composites and demonstrate that a simple rheological model for fiber composites, which assumes a constant, isotropic orientation distribution of the fibers, is able to describe the shear stress growth coefficient of the short fiber composite samples.

A high-entropy alloy showing gigapascal superelastic stress and nearly temperature-independent modulus.

High-performance superelastic materials with a combination of high superelastic stress, large elastic recovery strain, and stable elastic modulus over a wide temperature range are highly desired for a variety of technological applications. Unfortunately, it is difficult to achieve these multi-functionalities simultaneously because most superelastic materials have to encounter the modulus softening effect and the limited superelastic stress, whereas most Elinvar-type materials show small elastic strain limit. Here, we report a (TiZrHf)44Ni25Cu15Co10Nb6 high-entropy alloy that meets all these requirements. This alloy also shows good cyclic stability, thermally-stable capacity for elastic energy storage, high micro-hardness and good corrosion resistance, allowing it to operate stably in hostile environments. We show that its multi-functionalities stem from a natural composite microstructure, containing a highly-distorted matrix phase with strain glass transition and various structural and compositional heterogeneities from micro- to nano-scale. Our findings may provide insight into designing high-entropy alloys with unconventional and technologically-important functional properties.

On the High Elastic Modulus Mechanism of Iron Matrix Composites

High modulus steels are characterized by high specific strength and specific stiffness, which can be attributed to the presence of hard reinforced particles. This paper investigates two common iron matrix composites, namely Fe/TiB2 and Fe/TiC, prepared through in situ reaction, focusing on their structures and properties. The results show that both types of reinforced particles in the high modulus steels consist of coarse primary particles and fine eutectic particles. In comparison to Fe/TiC composites, Fe/TiB2 composites exhibit larger elastic modulus (210 GPa). The reasons for the phenomenon that the experimentally measured values of the modulus of elasticity are lower than the calculated values at equilibrium are discussed. It was found that microporous defects left over from the casting process are often present inside the coarse primary particles, which can be the source of microcracks or fractures. In addition, matrix/particle interface stability calculations revealed that TiB2 possesses a distinctive hexagonal structure, resulting in a smaller interfacial distance (d0 = 1.375 Å) with the ferrite matrix phase. The high interfacial work of adhesion (Wad = 3.992 J/m2) further confirms the stronger interfacial stability of the Fe/TiB2 composite in comparison to the Fe/TiC composite.

Influence of modifying additives on the structure and properties of biodegradable mixtures based on poly-3-hydroxybutyrate and nitrile butadiene rubber

Objectives. To investigate polymer composite materials based on poly-3-hydroxybutyrate (PHB) of microbiological origin and the synthetic nitrile butadiene rubber NBR-28. The biodegradability of PHB implies the possibility of its use for invasive medical purposes; however, this is significantly limited by its brittleness. The aim of this work was to search for approaches to altering the molecular structure of PHB-based composites, in order to impart them with sufficient physical and mechanical characteristics and increase their compatibility without violating biodegradability.Methods. Reaction mixtures contained the elastic material NBR-28, various modifiers (sorbitan oleate, epoxidized soybean oil, siloxane rubber), and additional polymer components (ethylene–vinyl acetate copolymer and polybutylene adipate terephthalate). The mixtures were prepared in a PL 2200-3 plasticorder (Brabender, Russia) by pressing, holding the material at 180°C under pressure for 3 min followed by quenching in cold water. The surfaces of the films and plates of the mixtures were studied using an Axio Imager Z2m optical microscope (Carl Zeiss, Germany) with the Axio Vision software at 50× and 200× magnification in reflected light. The mechanical properties of materials under tension were measured using an Instron 3365 universal tensile testing machine (Instron, United Kingdom).Results. The role of modifiers and polymer additives in the PHB–NBR-28 composites and their influence on the morphology of mixtures, crystallinity, and mechanical characteristics were established. The introduction of modifiers made it possible to reduce the average particle size of the NBR-28 phase in the PHB matrix by 30–50%, additionally changing their morphology. In this case, the uniformity of particle distribution increased, having a positive effect on the mechanical characteristics of the systems.Conclusions. It was shown that the modifiers change the morphology of mixtures, reduce the average particle size of the NBR phase by 30–50%, and positively affect the strength of the systems. Owing to changes in the structure of their interfacial layers and, as a consequence, physical and mechanical characteristics, the resulting composites render suitable for use in reparative bone and dental surgery, as well as for creating wound healing materials.

Differential pathological changes in colon microenvironments in acute and chronic mouse models of inflammatory bowel disease

ABSTRACT Inflammatory bowel disease is a chronic condition characterized by inflammation of the gastrointestinal tract, resulting from an abnormal immune response to normal stimuli, such as food and intestinal flora. Since the etiology of this disease remains largely unknown, murine models induced by the consumption of dextran-sodium sulfate serve as a pivotal tool for studying colon inflammation. In this study, we employed both acute and chronic colitis mouse models induced by varying durations of dextran-sodium sulfate consumption to investigate the pathological and immunologic characteristics throughout the disease course. During the acute phase, activated innate inflammation marked by M1 macrophage infiltration was prominent. In contrast, the chronic phase was characterized by tissue remodeling, with a significant increase in M2 macrophages and lymphocytes. RNA-sequencing revealed genetic changes in acute and chronic colitis, marked by the maintenance of genomic integrity in the acute phase and extracellular matrix dynamics in the chronic phase. These phase-specific alterations reflect the multifaceted physiological processes involved in the initiation and progression of inflammation in the large intestine, underscoring the necessity for distinct experimental approaches for each phase. The findings demonstrate that the factors shaping the large intestinal immune microenvironment change specifically during the acute and chronic phases of experimental inflammatory bowel disease, highlighting the importance of developing therapeutic strategies that align with the disease course.

Unveiling the Advantages of Silicon Nitride Nanoparticle Anodes for Enhanced Cyclic Stability, Rate Performance, and Mechanical Robustness.

Silicon nitride, known as a convertible-type silicon-based anode material, has emerged as a promising alternative to pure Si anodes, featuring improved cyclic stability, rate performance, and kinetics. This study reports on the electrochemical properties of silicon nitride nanoparticles as an anode material. It demonstrates that this anode outperforms a pure silicon anode in terms of cyclic stability and kinetics. Silicon nitride undergoes conversion during initial lithiation, forming a matrix phase that facilitates charge carrier transport that enhances performance. As a result, silicon nitride retains 73% of its initial charge capacity, whereas only 55% for pure silicon, after 350 cycles. The in situ-formed ion-conductive matrix promotes Li-ion transport, yielding an improved rate performance. At 1 C rate, silicon nitride achieves 585 mA h g-1 (38% of C/20 capacity) after 85 cycles, surpassing pure silicon's 470 mA h g-1 (22% of C/20 capacity). Electrochemical impedance indicates silicon nitride's faster ionic conductivity and lower resistance compared to pure silicon. Electrochemical dilatometer findings show less electrode thickness increase in silicon nitride (29%) than in pure silicon (60%) during initial lithiation. Silicon nitride demonstrates potential as an attractive anode material for future Li-ion batteries due to improved cyclic stability, superior rate performance, and stable electrode geometry.

Interpenetrating Composites: A Nomenclature Dilemma.

Interpenetrating phase composites are a novel class of heterogeneous structures that have recently gained attention. In these types of composites, one of the phases is topologically continuous and can maintain its structural integrity even if the other phase is removed. These composites are generally fabricated by casting, where the reinforcement penetrates into the precursor matrix as a continuous phase. However, the following dilemma arises: if the same two phases are combined by other powder metallurgical routes (due to differences in the fabrication and interfacial conditions), can they still be called interpenetrating phase composites? The reinforcement is added to the precursor matrix, as in any of the conventional composite processing methods. Most importantly, the reinforcement does not interpenetrate the matrix phase. The present Review discusses the various fabrication routes employed for the fabrication of these interpenetrating phase composites and attempts to identify the correct nomenclature for these composites fabricated via the powder metallurgical approach.

A Multi-Phase Analytical Model for Effective Electrical Conductivity of Polymer Matrix Composites Containing Micro-SiC Whiskers and Nano-Carbon Black Hybrids.

Multifunctional polymer composites containing micro/nano hybrid reinforcements have attracted intensive attention in the field of materials science and engineering. This paper develops a multi-phase analytical model for investigating the effective electrical conductivity of micro-silicon carbide (SiC) whisker/nano-carbon black (CB) polymer composites. First, CB nanoparticles are dispersed within the non-conducting epoxy to achieve a conductive CB-filled nanocomposite and its electrical conductivity is predicted. Some critical microstructures such as volume percentage and size of nanoparticles, and interphase characteristics surrounding the CB are micromechanically captured. Next, the electrical conductivity of randomly oriented SiC-containing composites in which the nanocomposite and whisker are considered as the matrix and reinforcement phases, respectively, is estimated. Influences of whisker aspect ratio and volume fraction on the effective electrical conductivity of the SiC/CB-containing polymer composites are explored. Some comparison studies are performed to validate the accuracy of the model. It is observed before the percolation threshold that the addition of nanoparticles with a uniform dispersion can improve the electrical conductivity of the polymer composites containing SiC/CB hybrids. Moreover, the results show that the electrical conductivity is more enhanced by the decrease in nanoparticle size. Interestingly, the composite percolation threshold is significantly reduced when SiC whiskers with a higher aspect ratio are added. This work will be favorable for the design of electro-conductive polymer composites with high performances.

Enhancing the durability of aluminium-foil anodes in rechargeable lithium batteries via uniformly distributed alloy addition in the matrix phase

Uniformly distributed Si in the Al matrix as a solid solution induces a pinning effect, prevents cracking of the Al grains, suppresses pulverization and improves the cycling stability of Al-foil anodes in rechargeable lithium batteries.

Study on PCD tool wear in pulsed laser assisted turning Al-50wt % Si alloy

Al-50wt % Si alloy is widely used in aerospace, automotive, electronic packaging and other fields due to its excellent material properties. However, the presence of reinforced particle phase differing in hardness from the alloy matrix phase leads to significant tool wear during turning with PCD tools. Therefore, this paper proposes a pulsed laser assisted turning (PLAT) method combining pulsed laser with conventional turning, which has unique advantages in reducing PCD tool wear. The effects of laser power, pulse width and frequency on tool wear during PLAT were studied by comparative experiments. And the potential mechanism of PLAT to reduce tool wear was revealed by finite element simulation. The results shown that PLAT effectively reduces PCD tool wear compared with conventional turning (CT). The increase of laser pulse width will aggravate tool wear. While, the increase of laser pulse frequency will reduce tool wear. Temperature is the main factor affecting the wear form. The tool mainly experiences abrasive wear at low temperature. However, the predominant type of tool wear shifts to adhesion as the increasing temperature. At the same time, EDS analysis shows that the rise in temperature results in an elevation of the O element content within the wear region, which proves that temperature is also the decisive factor affecting oxidative wear. This study provides valuable insights into actual machining involving Al-50wt % Si alloys and gives strategies for reducing PCD tool wear using PLAT.

Mechanical properties, degradation action, and biocompatibility of in situ nanoparticle-reinforced MgxZny/Zn composite prepared via roll bonding.

Zinc (Zn)-based alloys and composites are anticipated to emerge as a category of degradable metallic biomaterials with exceptional prospects for bone-implant applications owing to their superior biocompatibility and biofunctionality. Unfortunately, the limited strength of Zn alloys in their as-cast state restricts their use in clinical applications. In this study, we started with pure magnesium (Mg) powders and Zn sheets, and successfully fabricated MgxZny/Zn composites using accumulative roll bonding (ARB). The influence of varying ARB cycle numbers on their microstructures, performance in relation to mechanical parameters, corrosion resistance, and cytotoxicity was comprehensively studied. Following 15 ARB cycles, the composites demonstrated a refined Zn matrix phase with grains of 0.3 μm and uniformly distributed in situ nanoparticle reinforcements of Mg2Zn11 and MgZn2. The composites after 15 ARB cycles exhibited an ultimate tensile strength of 560 MPa, yield strength of 540 MPa, and elongation of 12 %, significantly better than the mechanical properties of most Zn alloys reported to date. The significant improvement in the composites' strength is primarily attributable to refinement of grain size and dispersion strengthening, both of which are facilitated by the in situ incorporation of nanoparticles. The corrosion rate reduced with more ARB cycles and after 15 ARB cycles the composites had an electrochemical corrosion rate of 150.2 μm/y and an immersion degradation rate of 50.6 μm/y. Further, an extract at 12.5 % concentration had a cell viability of 92.2 % toward MG-63 cells, indicating good biocompatibility. STATEMENT OF SIGNIFICANCE: This work reports on MgxZny/Zn composites fabricated by accumulative roll bonding (ARB). The composite after 15 ARB cycles exhibited an ultimate tensile strength of 560 MPa, yield strength of 540 MPa, and elongation of 12 %, significantly higher than the mechanical properties of most Zn alloys published in the literature to date. The corrosion rate of the composites decreased with increasing number of ARB cycles and after 15 ARB cycles they showed an electrochemical corrosion rate of 150.2 μm/y and immersion degradation rate of 50.6 μm/y. Further, a 12.5 % concentration extract showed a cell viability of 92.2 % in relation to MG-63 cells, indicating good biocompatibility.

A novel compatibilizer obtained from olive pomace oil maleate (OPOMA) and evaluation in PLA composite production

Alternative of using organic and biomass residues as additives or reinforcements in the production of composite materials has attracted great attention since the 2000s. However, when lignocellulosic biomass is used as natural fiber in composite production, it may have some disadvantages such as low interfacial bonding with the matrix phase. The most common methods used to strengthen the bonding between the matrix phase and the additive material is to use maleic anhydride (MA) as a compatibilizer and some chemicals such as dicumyl peroxide (DCP) as reaction initiators to increase the compatibilizing effect of MA. Therefore, in this study, olive pomace oil maleate (OPOMA) was prepared to be used in the production of PLA (polylactic acid) composites. Olive pomace obtained with ionic liquid pretreatment (OP-IL) in the previous studies of the authors and OPOMA were used in composite production with a biodegradable polymer of PLA. The composite was obtained by mixing 95PLA+5OP-IL by weight in twin-screw extruder at 190ºC for 10 minutes. Under the same conditions, the effect of OPOMA was evaluated by adding 0.5%, 1% and 2% ratio to PLA + OP-IL. In FTIR spectrum of OPOMA, a new symmetrical and asymmetric C=O bands were formed differently from olive oil. While the tensile strength of the PLA+OP mixture was approximately 10 MPa; the tensile strength value of PLA+OP-IL and PLA+OP-IL+OPOMA was around 60 MPa. The elasticity modulus showed less change compared to other mechanical properties. To conclude, it can be emphasized that oil maleates of lignocellulosic biomasses can be promising compatibilizer for biodegradable composite matrices.

Study of the Influence of Modification and Heat Treatment of Cast Iron Grinding Balls on Their Operational Properties

The study addresses the enhancement of wear resistance and impact strength of cast iron grinding balls used under intensive abrasive wear and impact conditions at ore processing plants. The primary aim is to improve the operating properties of cast iron by optimizing its chemical composition and introducing advanced thermal and chemical-thermal treatment methods, including controlled cooling. To achieve this goal, two alloyed cast iron compositions with added chromium, molybdenum, and nickel were used, and the base composition was further modified with titanium and titanium carbonitride to increase the microhardness of the matrix phases. Experimental samples underwent various heat treatment regimes, including quenching and normalization, to evaluate the effect of these processes on the microstructure, hardness, and impact resistance of the grinding balls. Microstructural analysis revealed that additional alloying elements and modifiers contributed positively to forming a more homogeneous and fine-grained structure with an increased proportion of carbide phases. The key findings indicated that the optimized structure of the cast iron grinding balls achieved 10 units higher hardness and 2-4 units greater impact resistance than the base composition after heat treatment. Furthermore, titanium and titanium carbonitride modifications enhanced the performance characteristics of the balls by several additional units. Thus, the developed treatment regimes and modified cast iron composition significantly increase the wear resistance of grinding balls, contributing to reduced grinding costs in industrial applications.

Mechanical Properties of Entirely Cement-Replacement Fly Ash-Based Geopolymers (G-SIFCON) and Cement-Based SIFCON: A Comparison Study

Environmentally friendly building materials known as geopolymers are made by combining high-alkalinity solutions with powder components rich in silica and alumina. It has long been known that adding fibers to the matrix phase can improve the mechanical characteristics of composite materials made for various uses. Among these are SIFCON composites, which are made by first inserting the fibers into the mold and then packing the gaps between the fibers with an extremely fluid matrix phase. The present study looked over the mechanical properties and efficiency of cement-based and geopolymer-based slurry infiltrated fiber concrete SIFCON and G-SIFCON. In the current study, for the production of both SIFCON and G-SIFCON composites, 7.5% steel fiber by volume fraction was utilized for this purpose. Therefore, sets of concrete specimens including cylinders and prisms were prepared and tested in accordance with standard specifications. The results obtained from the conducted tests prove that the 7.5% of steel fiber ratio can be used effectively to improve the mechanical performance of G-SIFCON and SIFCON composites. Furthermore, the cement-based SIFCON can be effectively replaced by fly ash-based geopolymers. Also, for composites made with fly ash-based geopolymers (G-SIFCON), high compressive strength slurries may exhibit more enhancement in mechanical properties than normal strength slurries.

Axial Zero Thermal Expansion with Good Mechanical Strength in the Ni-Doped Kagome Ho2Fe17 Magnets.

Zero thermal expansion (ZTE) metals have drawn considerable scientific and practical interest due to their excellent dimensional stability. However, the narrow temperature window and inherent brittleness of the ZTE compounds severely limit their processing and application. Herein, an axial ZTE alloy (Ho2Fe13.8Ni3.2, αl = -0.3 × 10-6 K-1 and 110-545 K) is realized in the Ni-doped Ho2Fe17 magnets, which effectively broadens the ZTE temperature window. Combining the variable-temperature neutron diffraction and magnetization measurements, we reveal that the content of Ni tailors the ferromagnetic ordering of the Fe sublattice and regulates lattice negative thermal expansion. Good compressive strength is subsequently achieved by introducing excess Fe in the axial ZTE composition, namely, the dual-phase alloy of Ho2Fe13.8Ni3.2-Fe5 (αl = +0.3 × 10-6 K-1, 110-535 K, and 1.19 ± 0.2 GPa). Neutron diffraction and scanning electron microscopy reveal that the α phase (Fe-Ni) precipitates in the hexagonal phase matrix play a critical role in maintaining ZTE characteristics and enhancing compressive strength. The present chemical design approach may be applicable for obtaining high-performance axial ZTE alloys.

Phase composition and crystal structure of alumina-zirconia ceramics with varying LaAl11O18 content

This study investigates the phase composition and structure of alumina-zirconia ceramics containing varying amounts of LaAl11O18 plates. The research addresses the significant influence of lanthanum hexaaluminate on the structural and physical properties of these ceramics, specifically focusing on its effects on crystal lattice parameters and phase volume content. Using synchrotron radiation and the Rietveld refinement method, the influence of lanthanum hexaaluminate content on the parameters of crystal lattices and phase content of the investigated materials were evaluated. Scanning electron microscopy was employed to analyze the grain size, morphology, and distribution within the material matrix. High-purity powders of α-Al2O3, 3Y-ZrO2, and La2O3 were used as initial materials. The materials were obtained by the pressureless sintering techniques in two hours at 1520 °C. A series of materials comprising 50 wt.% ZrO2 and varying percentage (0–15 wt.%) of LaAl11O18 was obtained. The coherent scattering regions of the alumina and zirconia matrix phases remained relatively unchanged in the composites. The coherent scattering regions of lanthanum hexaaluminate increased significantly with its concentration in the materials. The analysis revealed a decrease in alumina grain size with increasing LaAl11O18 content, while the size of the LaAl11O18 plates displayed a consistent increase. The best properties were observed for alumina-zirconia ceramics with the calculated content of lanthanum hexaaluminate of 12 wt.%. The relative density of this material is 95.3±0.3%, the hardness is 1490 Hv, and the indentation fracture resistance is 7.2±0.3 MPaThis study investigates the phase composition and structure of alumina-zirconia ceramics containing varying amounts of LaAl11O18 plates. The research addresses the significant influence of lanthanum hexaaluminate on the structural and physical properties of these ceramics, specifically focusing on its effects on crystal lattice parameters and phase volume content. Using synchrotron radiation and the Rietveld refinement method, the influence of lanthanum hexaaluminate content on the parameters of crystal lattices and phase content of the investigated materials were evaluated. Scanning electron microscopy was employed to analyze the grain size, morphology, and distribution within the material matrix. High-purity powders of α-Al2O3, 3Y-ZrO2, and La2O3 were used as initial materials. The materials were obtained by the pressureless sintering techniques in two hours at 1520 °C. A series of materials comprising 50 wt.% ZrO2 and varying percentage (0–15 wt.%) of LaAl11O18 was obtained. The coherent scattering regions of the alumina and zirconia matrix phases remained relatively unchanged in the composites. The coherent scattering regions of lanthanum hexaaluminate increased significantly with its concentration in the materials. The analysis revealed a decrease in alumina grain size with increasing LaAl11O18 content, while the size of the LaAl11O18 plates displayed a consistent increase. The best properties were observed for alumina-zirconia ceramics with the calculated content of lanthanum hexaaluminate of 12 wt.%. The relative density of this material is 95.3±0.3%, the hardness is 1490 Hv, and the indentation fracture resistance is 7.2±0.3 MPa.m1/2.

Effects of raw powder characteristics on microstructure and mechanical properties of W[sbnd]20Cu composites manufactured by SLM

Selective laser melting (SLM) technique is a promising method to achieve near-net-shaping of WCu complex components. In this work, two types of raw powers were prepared, including spherical WCu composite powder and mixed WCu powder. Effect of the raw powder characteristics on the microstructure and mechanical properties of W20Cu alloy were investigated. The results show that the composite powder enables the WCu composites to possess a high relative density (95.1 %), homogeneous microstructure and super mechanical properties (204.40 ± 1.73 HBW for hardness and 500 MPa for tensile strength). Remarkably, compared to mixed powder, the tensile strength and hardness are increased by 37 % and 74.2 %, respectively. This good effect stems from the composite powder with good sphericity degree and uniform structure. As a result, a dense specimen with refined W particles (3.05 μm) evenly embedded in the Cu matrix phase, accompanied by dislocation structure and sub-grains within the Cu matrix are obtained, contributing to the superior mechanical properties of the composites. The present work offers a strategy for developing high-performance WCu composites using SLM technology.

Research Progress on the Impact Resistance of Basalt Fiber-Reinforced Polymer Composites

Abstract Basalt fibers exhibit excellent properties and have diverse applications. This paper thoroughly investigates the impact resistance of polymer matrix composites reinforced by basalt fibers and analyzes the failure mechanisms during impact, including micro-deformation, delamination, and fiber fracture. Basalt fiber-reinforced resin matrix composites consist of a reinforcement phase, a matrix phase, and an interface phase. To strengthen the material’s resistance to impacts, various approaches have been explored, including optimizing the matrix resin (e.g., selecting vinyl resin and toughening treatments), optimizing the reinforcement phase (e.g., fiber hybridization, morphology optimization, and interlayer hybridization), and improving the interface phase (e.g., coupling agent modification and carbon nanotube grafting). These optimization measures can significantly enhance the impact resistance of basalt fiber-reinforced polymer materials under low-velocity impact loads. Under high-velocity impact loads, increasing the number of laminate layers or employing three-dimensional weaving techniques can significantly improve the material’s impact resistance. These research findings aim to provide a theoretical foundation and practical references for the application of basalt fiber-reinforced polymer materials within the domain of impact resistance.

Creep rupture of smoothed and notched DD6 single crystal superalloy specimens subjected to high-temperature hot corrosion

This work studies the creep rupture behaviors of both smoothed and V-notched DD6 Ni-based single crystal superalloy specimens under both air and corrosion conditions, within a stress range of 300 to 700 MPa at 950 °C. The corrosive medium used consisted of a mixed salt containing 95 wt% Na2SO4 and 5 wt% NaCl. Experimental results revealed that notched specimens exhibited a creep rupture life extended by 6–16 times compared to smoothed specimens, with the extension becoming more pronounced as the stress concentration increased. High-temperature hot corrosion (HTHC) shortened the creep rupture time by up to 75 %. A significant HTHC-creep interactive effect was found through comparative creep experiments in air and corrosion conditions. The HTHC affected the fracture modes of the specimens, with factors such as the amount of salt infiltration into the superalloy, the corrosion duration, and specimen configurations playing critical roles. Microstructural analysis revealed that, compared with γ′ precipitates, γ matrix phase was more prone to creep damage and was more susceptible to corrosion.