Plastic Properties Research Articles

Exploring the impact of CO2 sequestration on plastic properties, mechanical performance, and microstructure of concrete

In view of global warming, carbon sequestration techniques are being employed across the globe to minimize the damaging effects of greenhouse gases on the environment. Studies have revealed that adding CO2 during the mixing or curing stage of concrete enhances its mechanical properties and long-term durability. This study aims to examine the effect of CO2 addition during the mixing stage on the plastic, mechanical and microstructural properties of concrete. Various CO2 dosages, ranging from 0.1 to 1%, were injected during mixing to analyze the plastic and hardened properties of concrete. CO2 primarily reacts with calcium hydroxide in concrete to form calcium carbonate (CaCO3), thereby densifying its microstructure and improving its compressive strength by 10–20%. An optimum strength of up to 20% was achieved with 0.75% dosage. Additionally, the results show a 5–10% improvement in flexural and split tensile strength with CO2 addition over the control mix, with 0.75% dosage yielding optimal strength. Semi-adiabatic calorimetry test on early hydrating concrete shows a 14% peak temperature rise at 0.75% CO2 dosage compared to control concrete, indicating enhanced early-age strength development. Thermal Pyrolysis tests, microscopy and infrared spectroscopy indicated the presence of CaCO3, thereby confirming the carbonation process. However, CO2 dosages above 0.5% by weight of cement resulted in a drop in the workability of concrete in the plastic stage. This research attempts to create a simplified CO2 sequestration process in concrete, develop a predictive model to estimate the compressive strength and utilize material characterization techniques to identify the mineralization process.HighlightsInjecting CO2 into fresh concrete improves its strength and lowers its environmental impact.A multiple linear regression model predicts the compressive strength of CO2-injected concrete.Semi-adiabatic calorimetry shows that CO2 injection speeds up early hydration.Thermal Pyrolysis detects mass loss stages linked to dehydration and calcite breakdown.Microscopy and spectroscopy indicate CaCO3 crystal formation in CO2-sequestered concrete.

Geomechanical and Hydraulic Behavior of Impermeable Layers for Earthworks

Objective: The objective of this study is to investigate the mechanical and hydraulic behavior of fine sandy soil mixtures from the Coastal Plain of Rio Grande do Sul with bentonite, assessing their technical feasibility as an impermeable layer for earthwork projects. Theoretical Framework: El marco teórico explora la impermeabilización de vertederos sanitarios, destacando la eficacia de los liners para contener contaminantes y el uso de bentonita como aditivo para suelos granulares. Estudios previos señalan mejoras en la conductividad hidráulica y la plasticidad de mezclas de suelo-bentonita, especialmente en regiones con escasez de materiales arcillosos de alta calidad. Method: The method includes laboratory tests with natural soil and mixtures containing different bentonite contents. Physical, granulometric, plasticity, compaction, hydraulic conductivity, and mechanical resistance properties were evaluated. Results and Discussion: The natural soil proved unsuitable for use as an impermeable layer. The results show that the addition of bentonite significantly improved the soil's hydraulic conductivity, with 6% by dry weight achieving values suitable for impermeable layers. However, increasing bentonite content reduced the friction angle, indicating a decrease in mechanical strength. Research Implications: The research highlights the potential of soil-bentonite mixtures as a sustainable solution for impermeable layers in earthwork projects, particularly in regions with limited availability of clayey soils. The results provide technical support for the use of local materials, contributing to the feasibility of environmental engineering projects tailored to regional characteristics. Originality/Value: The research is original in exploring soil-bentonite mixtures as a sustainable solution for impermeable layers in coastal plains, a region with scarce suitable clayey soils. Its contribution lies in the technical evaluation of local materials, promoting innovative and environmentally adapted alternatives for engineering projects in challenging contexts.

Study on Mechanical and Thermal Properties of Plasticizer with Epoxidation Waste Cooking Oil

This study investigates the mechanical and thermal properties of plasticizers formulated with Epoxidized Waste Cooking Oil (EWCO). The primary objective is to evaluate the influence of EWCO as a plasticizer on the performance of polylactic acid (PLA) composites. Epoxidation of waste cooking oil with and without catalyst (sulfuric acid) is applied before mix with PLA. PLA, a biodegradable polymer, is chosen due to its environmental benefits, but its brittleness limits its application. By incorporating varying weight ratios of EWCO (2.5%, 5%, 7.5%, and 10%), both with and without the presence of a catalyst, the tensile strength and thermal stability of the resulting composites are assessed. The mechanical properties were analyzed through tensile strength tests, revealing that the inclusion of EWCO generally decreases the tensile strength of PLA. Notably, the addition of a catalyst significantly enhances the tensile strength, demonstrating the potential of catalysts in optimizing the mechanical properties of PLA/EWCO composites. Thermal properties were evaluated a melting point and a glass transition temperature (Tg). Results indicate that EWCO influences the thermal stability of PLA, with variations depending on the presence of a catalyst and the EWCO concentration. The results in this research also shows that sulfuric acid is used as a catalyst in the epoxidation process of waste cooking oil (WCO) to produce epoxidized waste cooking oil (EWCO) the epoxide yield achieve around 85% and give shorter reaction time of 4 hours. This research contributes to the understanding of how EWCO, a sustainable and eco-friendly plasticizer, affects the mechanical and thermal properties of PLA composites. The findings of this study shows that EWCO enhances flexibility, the mechanical strength and thermal stability This study provides a foundation for future research aimed at developing optimized PLA/EWCO composites for diverse applications, promoting sustainability in material science.

Progress in the Study of Occurrence, Distribution, Material Flows, and Environmental Release of Substances of Very High Concern （SVHCs） in Plastics

Plastic additives provide plastics with excellent functions such as plasticizing, flame retardant, and antioxidant properties and are widely used in various plastics. Of these, 189 plastic additives have been included in the European Union's Candidate List of substances of very high concern （SVHCs） due to their potential environmental and health risks. These SVHCs are mainly used in PVC, PUR, and PE plastics and in the packaging, automotive, construction, electronic and electrical equipment, and textile sectors. Plasticizers and flame retardants are the most widely used and therefore the focus of SVHC risk assessment and risk management. Existing studies have carried out material flow analysis （MFA） for SVHCs in plastics, revealing the environmental and health risks of typical flame retardants and plasticizers throughout the product life cycle, such as polybrominated diphenyl ethers （PBDEs）, hexabromocyclododecane （HBCD）, and phthalic acid esters （PAEs）. A large amount of SVHCs enter waste streams at the end of the product life cycle, highlighting the importance of strengthening waste management for SVHCs risk management. In addition to the release of SVHCs from plastic products into the environment, plastic leakage is another important source of environmental release of SVHCs. Plastic debris that have been in the environment for a long time continue to release SVHCs and pose a long-term threat to the ecosystem and human health. In the future potentially hazardous chemicals must be crucially identified in different types of plastics and to assess their environmental release during their life cycle, in particular by establishing a database on hazardous chemicals in plastics and measuring emission factors, optimizing dynamic material flow analysis （d-MFA）, as well as studying the release mechanisms of hazardous chemicals from plastic leakage.

Mechanical properties analysis of PP-LGF40 and DC01 automotive front-end frames based on lightweight technology

In this paper, a front-end frame of a new energy vehicle is designed, and the CATIA model is established by combining the relevant parameters of the target material, and the mechanical properties of different materials under different working conditions are analyzed in depth by using ANSYS workbench software. Through parametric design, geometric modeling, material properties, and boundary conditions, the mechanical properties of all-metal, all-plastic, and mixed plastic and steel front-end frames were simulated for comparative analysis and research. In the simulation process, the static mechanical performance of the front-end frame is analyzed using the parameter indexes under different working conditions. The study shows that PP-LGF40 material has insufficient stiffness but very light mass, according to the observed stress maximum point and deformation maximum location in the vicinity of the hood main lock and upper frame, the combination of steel DC01 + PP-LGF40 is finally adopted, the main lock and upper frame part with the largest deformation is made of steel DC01 material, while the lower frame part with smaller deformation is made of lighter PP-LGF40 material. The mass of the optimized front-end frame is 5.1201 kg, which is 35.52% lighter than the steel DC01 front-end frame of 7.9417 kg, and the lightweight effect is obvious. After ANSYS analysis and calculation of the main lock of the front-end frame in 2500 N load, the maximum compressive force can be 523.38 MPa, and the maximum deformation of the main lock is 1.3552 mm.The model of the automobile front-end frame made of a mixture of plastic and steel materials uses steel in the area of the larger force, and uses plastic in the other areas, which can not only ensure the mechanical properties of the requirements, but also achieve the requirements of lightweight.

Inhibition of furin in CAR macrophages directs them toward a proinflammatory phenotype and enhances their antitumor activities

Chimeric antigen receptor (CAR)-T-cell therapy has revolutionized cellular immunotherapy, demonstrating remarkable efficacy in hematological cancers. However, its application in solid tumors faces significant challenges, including limited T-cell infiltration and tumor-induced immunosuppression. Given the prominent role of macrophages in the tumor microenvironment, their phenotypic plasticity and inherent antitumor properties, such as phagocytosis, offer a promising avenue for therapeutic intervention. This study focuses on the development of a second generation of CAR macrophages (CAR-Ms). We elucidated the role of the proprotein convertase furin in macrophages, demonstrating its overexpression in the presence of tumor cells. Importantly, furin inhibition maintains a proinflammatory macrophage phenotype, potentially redirecting them towards an antitumor state. Compared to furin-expressing counterparts, furin-inhibited CAR-Ms exhibited heightened antitumor phagocytic activity against breast cancer cells and ex vivo patient-derived tumoroids. Notably, they sustained a persistent proinflammatory profile, indicative of enhanced tumoricidal potential. Additionally, furin-inhibited CAR-Ms secreted factors that promote T-cell activation, offering a means to modulate the tumor microenvironment. In summary, our work highlights the translational potential of furin-inhibited CAR-Ms as a potent cellular therapy to mitigate macrophage exhaustion within the tumor environment. By capitalizing on macrophage-mediated antitumor responses, these findings pave the way for the development of second-generation CAR-M therapeutic strategies tailored for solid tumors.

Camelina sativa (L.) Crantz straw and pomace as a green filler for integral skin polyurethane foam

The development of efficient methods for obtaining cellular materials with improved functional properties is a constant challenge for the plastics industry, including the polyurethane industry. In recent years, efforts have been made to obtain cheap and easily available raw materials that can be used as foam fillers. In addition to commercially used synthetic fillers, more and more attention is paid to materials of natural origin, in particular to agricultural and industrial waste. This solution not only meets the assumptions of the "Green Chemistry" concept but also creates the opportunity to improve the properties of plastics while reducing their production costs. This study focuses on the use of naturally derived materials as fillers in flexible integral polyurethane foams (Integral Skin Foams, ISFs) to produce economically advantageous and ecologically sustainable composite materials. Waste materials such as Camelina sativa (L.) Crantz straw and pomace were used as biofillers. The obtained samples were used to determine the processing parameters and functional properties of the foams: hardness, tensile strength, elongation at break and permanent deformation after compression. In the case of both straw and pomace, an increase in growth time and an increase in the free density of the foams were observed with an increase in the amount of added plant material. The analysis of morphology and chemical structure of the obtained composites led to the conclusion that the cellular structure, skin thickness, and functional groups present in biofillers had a direct impact on the functional properties of ISF. For most composites, a significant improvement in mechanical parameters was observed compared to the reference foam. The obtained results confirmed the utility potential of Camelina sativa (L.) Crantz straw and pomace. The main research assumption has been fully implemented that focused on obtaining innovative polyurethane composites with improved functional properties.

Small-Scale Aqueous Suspension Preparation using Dual Centrifugation: The Effect of Process Parameters on the Sizes of Drug Particles

The dual centrifugation approach has in the recent years emerged as a powerful milling tool to prepare pharmaceutical suspensions in submicron range with a fast-milling capacity by milling 40 samples simultaneously in 2 mL vials. While there is some standardized milling conditions described in the literature when preparing aqueous suspensions with dual centrifugation, a more systematic and experimental understanding of the milling process to evaluate the impact of different process variables in the dual centrifuge on the final sizes of the suspended drug particles independent of the drug compound used. Overall, the present study demonstrated the applicability of the dual centrifuge for small-scale screening purposes and showed the impact of process parameters on the physical attributes of prepared suspensions. In the present work, the rate of size reduction on three different model compounds, i.e., cinnarizine, haloperidol, and indomethacin, was found to be mostly influenced by the milling speed, size of milling beads, and the bead loading during milling, whereas the rotor temperature did not affect the particle size profiles when stabilized with polysorbate 20 during milling with dual centrifugation. Smaller particle sizes were in general obtained at the highest milling intensity, i.e., 1500 rpm, smallest bead size, i.e., 0.2 mm, and higher bead loadings (42%, 56%, and 83%). The grinding limit of approximately 0.50 µm, 0.70 µm, and 0.35 µm for cinnarizine, haloperidol, and indomethacin, respectively, was achieved relatively fast, i.e., 30 minutes of milling at the specified conditions, compared to when suspensions were milled with larger bead sizes (i.e., 1.0 mm), lower milling intensities (e.g., 1000 rpm), and lower bead loadings (e.g., 14 or 28%). The study further confirmed that a higher milling intensity was necessary during milling of haloperidol suspensions probably due to the compounds predominantly plastic properties. Sizes of indomethacin particles increased with longer milling runs up to 240 minutes and also higher bead loadings of 56% and 83%. These observations were further supported by the color conversion from white to yellow of indomethacin suspensions which indicated generation of small quantities of amorphic material after milling with a high milling intensity. Upscale investigations showed comparable particle size profiles for all three model compounds while milling at 1500 rpm for five minutes.

Female mice exhibit similar long-term plasticity and microglial properties between the dorsal and ventral hippocampal poles

The hippocampus is a heterogenous structure that exhibits functional segregation along its longitudinal axis. We recently showed that in male mice, microglia, the brain’s resident immune cells, differ between the dorsal (DH) and ventral (VH) hippocampus, impacting long-term potentiation (LTP) mainly through the CX3CL1-CX3CR1 signaling. Here, we assessed the specific features of the hippocampal poles in female mice, demonstrating a similar LTP amplitude in VH and DH in both control and Cx3cr1 knock-out mice. In addition, the expression levels of Cx3cr1 and Cx3cl1 mRNA do not differ between the two poles in control mice. These data support the critical role of the CX3CL1-CX3CR1 signaling in setting the physiological amount of plasticity, equally between poles in females. Although BDNF is higher in DH compared to VH, the expression levels of inflammatory markers involved in plasticity and of phagocytosis markers in microglia are comparable between the two poles. In accordance, microglia soma and arborization area/perimeter, and microglial ultrastructure are similar across regions, with the exception of microglial density, cells arborization solidity and circularity that are higher in DH. Understanding the molecular processes underlying microglial sex differences and their potential implications for plasticity in specific brain regions is of major importance in physiological and pathological conditions.

Mesenchymal stem/stromal cells: dedicator to maintain tumor homeostasis.

Mesenchymal stem/stromal cells （MSCs） act as a factor in tumor recurrence after drug treatment with their involvement observed in various cancer types. As a constituent of the tumor microenvironment (TME), MSCs not only provide support to tumor growth but also establish connections with diverse cell populations within the TME, serving as mediators linking different tumor-associated components. MSCs play an important role in maintaining tumor progression due to their stem cell properties and remarkable differentiation capacity. Given the intensification of tumor research and the encouraging results achieved in recent years，the aim of this article is to investigate the supportive role of MSCs in tumor cells as well as in various cellular and non-cellular components of the tumor microenvironment. Furthermore, the article shows that MSCs do not have a specific anatomical ecological niche and describes the contribution of MSCs to the maintenance of tumor homeostasis on the basis of homing, plasticity and tumor-forming properties. By elucidating the critical roles of different components of TME, this study provides a comprehensive understanding of tumor therapy and may offer new insights into defeating cancer.

Sand bed river dynamics controlling microplastic flux

Microplastic contamination of river sediments has been found to be pervasive at the global scale and responsive to plastic and sediment bed properties, the flow regime and the river morphology. The physical controls governing the storage, remobilization and pathways of transfer in sand bed rivers remain unquantified. This means it is not currently possible to determine the risks posed by microplastic contamination within these globally significant river systems. Using controlled flume experiments we show that sand bed rivers can store up to 40% of their microplastic load within the sediment bed indicating that these environments can act as resilient sinks of microplastics. By linking bedform dynamics with microplastic transport characteristics we show that similarities exist between granular transport phenomena and the behavior, and hence predictability, of microplastic flux. Specifically, we demonstrate the inverse relationship between bedform celerity and microplastic retention within the bed can be used to predict microplastic flux. Further, we show that, in these environments, microplastic shape is more important than previously thought in controlling the fate of microplastics. Together, these findings are significant since they have important implications for the prediction and hence management of microplastic contamination in sand bed environments.

Compressive strength of bentonite concrete using state-of-the-art optimised XGBoost models

ABSTRACT This study proposes an advanced soft-computing approach for predicting the compressive strength (CS) of bentonite concrete using an optimised XGBoost model. Bentonite is valued as a partial cement replacement for its environmental benefits and improved concrete properties, but predicting CS remains challenging due to complex constituent interactions. The study’s motivation is the increasing interest in sustainable materials like bentonite as a partial cement replacement, which presents unique challenges due to its high plasticity and swelling properties. While hybrid XGBoost models are effective in civil engineering, their application for CS prediction in concrete is limited. This research simulates hybrid XGBoost models using particle swarm optimisation (PSO), genetic algorithm (GA), and dragonfly optimisation (DO), supported by a comprehensive dataset with varied mix proportions and multicollinearity analysis. Hyperparameter tuning and feature selection techniques were applied to optimise the model’s performance. The results demonstrate that the PSO-XGBoost is the best performing model (R2 = 0.974, RMSE = 0.038), followed by DO-XGBoost and GA-XGBoost. All the hybrid XGBoost models perform better than conventional XGBoost model. The developed robust soft-computing based prediction methodology can serve as a reliable alternative tool for predicting the CS of bentonite concrete, thereby facilitating the design and development of sustainable concrete mixtures with enhanced performance characteristics.

Performance-Oriented and Deformation-Constrained Dual-topology Metamaterial with High-Stress Uniformity and Extraordinary Plastic Property.

The study of classical mechanical metamaterials has overwhelmingly remained at the elastic stage, while the increase in extreme speeds of vehicles and aircraft has created an urgent need and demanding requirements for excellent plasticity performance. Although some plastically deformable metamaterials exist, high initial peak stresses, short plastic strokes, and low plastic stresses limit their applications considerably. Here, an ideal malleable large-deformation metamaterial featuring high-stress levels and stability is reported. A performance-oriented multidimensional performance expansion strategy is adopted to obtain the bionic triangular corrugation-based plate lattice (TCPL) metamaterial. Then, the deformation constraint strategy that TCPL is innovatively used as the main topology with lateral expansion and buckling inhibited by the inserted enhancing topology is proposed, thus obtaining the built-in dual-topology enhanced TCPL (ETCPL). The ETCPL is again substantially strengthened in stress uniformity with almost no gradient and mechanical properties with strain energy improved by 51.56%. They are much more robust than typical multicellular materials, with the largest performance enhancement reaching 18 667.19%. In addition, the strength-density performances of both metamaterials significantly exceed the predictions of Gibson-Ashby model up to 75.2% maximum. The unprecedented performance confirms that multidimensional performance expansion strategy and deformation constraint strategy have created new design guidelines for ideal high-performance plastic metamaterials.

Upgrading Mixed Plastic Waste through Industrial Symbiosis: Pseudoductile Regenerated Cellulose Fiber-Reinforced Shredder Residue Composites.

The mechanical performance of mixed plastic waste from shredder residue is hindered by brittleness and catastrophic failure, limiting its potential applications. In this study, the mechanical properties of mixed plastic is enhanced by reinforcement with rayon fibers through a wet powder impregnation process to leverage the fiber's ductility and entanglement. However, mixed plastic remains poorly dispersed in water during the composite manufacturing, resulting in poorly consolidated composite, which further deteriorates the mechanical properties of mixed plastic from 1.5% strain-at-break to 0.7%. To address this issue, the addition of sodium dodecyl sulfate (SDS) surfactant is explored, where the optimal concentration is found beyond the critical micelle concentration at 10 mM. Lowering the surface tension of water and the adsorption of the SDS on the mixed plastic powder surface facilitated homogeneous dispersion of mixed plastic particles, resulting in well-consolidated rayon fiber-reinforced composites. The 30 wt % rayon fiber-reinforced mixed plastic composite prepared with SDS demonstrated a progressive failure behavior, exhibiting a strain-at-break of 8% and a remarkable 350% increase in impact strength compared to unreinforced mixed plastic. This approach provides a platform to overcome the inherent limitations of mixed plastic waste, offering waste-derived plastic alternatives and reducing the need for fossil-derived virgin materials for a wide range of noncritical applications.

Study on the mechanism of waterborne polyurethane modified ultrafine ground calcium carbonate and its properties in polypropylene plastics

AbstractGround calcium carbonate (GCC) has the effect of reducing the incremental cost and improving the application performance as a plastic filler. In this study, waterborne polyurethane (WPU) was employed as a novel modifier for the wet modification of GCC. Polypropylene (PP)‐based composites incorporating GCC were then prepared for mechanical properties testing. The oil absorption value, wetting contact angle, and settling time in kerosene indicated that the modified GCC achieved an excellent modification effect with a WPU dosage of 2.0 wt%. The X‐ray Diffraction, Fourier Transform Infrared Spectroscopy, and X‐ray Photoelectron Spectroscopy results indicate that WPU was successfully coated on the surface of the GCC. SEM images revealed improved wettability and compatibility of GCC in the composites after modification. The mechanical tests showed that the GCC‐WPU/PP composites exhibited enhanced properties, including a flexural strength of 107 MPa, impact strength of 9.54 kJ/m2, tensile strength of 29.7 MPa, and an elongation at break of 30.9%.Highlights WPU was innovatively used as a modifier of GCC. An optimal modification effect was gained at the low dosage (2.0 wt%). GCC has excellent compatibility and wettability in PP composites. The obtained PP‐based composites have better mechanical properties. The study has the potential to apply GCC in plastics and other industries.

Mitochondrial plasticity: An emergent concept in neuronal plasticity and memory

Mitochondria are classically viewed as ‘on demand’ energy suppliers to neurons in support of their activity. In order to adapt to a wide range of demands, mitochondria need to be highly dynamic and capable of adjusting their metabolic activity, shape, and localization. Although these plastic properties give them a central support role in basal neuronal physiology, recent lines of evidence point toward a role for mitochondria in the regulation of high-order cognitive functions such as memory formation. In this review, we discuss the interplay between mitochondrial function and neural plasticity in sustaining memory formation at the molecular and cellular levels. First, we explore the global significance of mitochondria in memory formation. Then, we will detail the memory-relevant cellular and molecular mechanisms of mitochondrial plasticity. Finally, we focus on those mitochondrial functions, including but not limited to ATP production, that give mitochondria their pivotal role in memory formation. Altogether, this review highlights the central role of mitochondrial structural and functional plasticity in supporting and regulating neuronal plasticity and memory.

Damage Characteristics and Mechanical Properties of DD6 Single‐Crystal Alloy Based on Crystal Plasticity Theory under Uniaxial Tensile Conditions

Herein, the mechanical behavior and damage characteristics of DD6 nickel‐based single crystal alloy under different crystal orientation conditions are studied based on the theory of crystal plasticity coupled with damage constitutive equations using the crystal plasticity finite‐element method. The results indicate that the crystal plastic finite‐element model coupled with damage constitutive equations can well describe the entire deformation process from elasticity to damage. Under the reference orientation condition, the damage starts from the center position inside the test specimen and extends to the surrounding areas. The stress value in the damaged area decreases gradually from the periphery to the center of the test specimen, and an external stress reduction zone is formed. The crystal exhibits the best elasticity properties in the [0, 1, 1] orientation and the best plasticity properties in the [0, tan22.5°, 1] orientation. As the rotation angle of crystal orientation increases, the damage zones of X‐Z, Z‐Y, and X‐Y sections all exhibit clockwise rotation characteristics.

PHYSICAL-MECHANICAL PROPERTIES OF DYNAMICALLY VULCANIZED BASALT CONTAINING PLASTICS BASED ON COMPATIBILIZED POLYPROPYLENE

The influence of the content of basalt and Exxelor PО1020 compatibilizer on the main physical-mechanical and thermophysical characteristics of composites based on polypropylene is considered. It has been established that the use of a compatibilizer in an amount of 1.0–3.0 wt. % can significantly improve such properties of basalt plastics as tensile strength, yield strength, elongation at break, flexural strength, Vicat softening temperature, and melt flow rate. The possibility of cross-linking basalt plastics with sulfur and dicumyl peroxide is considered, and their role in changing their basic physical-mechanical parameters is determined. A theoretical analysis is given of the formation of an interfacial region with the participation of a compatibilizer and basalt. A micrograph showing the redistribution of basalt in the composition of compatibilized polypropylene is given by electron microscopy. The optimal concentrations of vulcanizing agents are determined, at which the highest strength properties are achieved, provided that elongation at break and the melt flow rate are maintained at a satisfactory level. It has been established that the optimal content of dicumyl peroxide is 0.25–0.5% wt

Optimization of microstructure and mechanical properties of 7075 aluminum alloy by equal channel angular pressing technology

Abstract The equal channel angular pressing technology, as an effective technique for modifying the surface of a material, has had a significant impact on the microstructure and mechanical properties of the 7075 aluminum alloy. The study achieved the refinement of 7075 aluminum alloy grains and the homogenization of the second phase particle distribution through equal channel angular pressing technology, thereby significantly improving the strength and plasticity of the material. Through orthogonal experimental design, the effects of extrusion angle, extrusion speed, and remelting temperature on material properties were studied. The results showed that appropriate ECAP parameters could effectively regulate the microstructure of 7075 aluminum alloy, thereby optimizing its mechanical properties. Especially in the analysis of equivalent strain rate, when the extrusion angle was 50°, the position of the maximum equivalent strain rate at the forefront point remained unchanged, but the equivalent strain rate decreased to 0.107-1. In the aging hardness analysis, when the number of equal channel angular pressing passes was 3, the aging hardness of G group 7075 aluminum alloy increased to 195HV in the first 5 minutes. The equal channel angular pressing technology can optimize the internal structure of 7075 aluminum alloy and improve the material's plasticity and mechanical properties. The research provides important technical support for the application of 7075 aluminum alloy in high-end equipment manufacturing.

Research on Mechanical Properties of High‐Manganese Steel Coating Manufactured by Coaxial Powder‐Feeding Laser Cladding

Due to the process complexity of the high‐carbon high‐manganese steel (HMnS) in casting and arc welding, this article propose the coaxial powder‐feeding laser cladding (LC) of HMnS coating using self‐developed HMnS powders. Firstly, high‐carbon HMnS coatings are prepared on the 16Mn substrate using coaxial powder‐feeding LC technology. It has a single austenite phase, without large defects such as pores and cracks. Then, ultrasonic shock peening is used to harden the HMnS coating, and the mechanical properties such as microhardness, impact toughness, wear and tensile properties are measured, which prove that HMnS coating has excellent working hardening, plasticity, toughness, and wear resistance properties. Finally, transmission electron microscopy is used to investigate the coupling effects such as dislocations, multiple twinning, and stacking faults on the HMnS coating after tensile fracture (true strain 39.2%). The deformation strengthening mechanism based on the dynamic Hall–Petch effect is revealed. The research results provide a new method for the preparation of high‐carbon HMnS coatings, and a new idea for expanding the application of high‐carbon HMnS.