Improvement In Strength Research Articles

Nanometer-Scale Tunable mesopores in silica fillers for Facile enhancement of epoxy adhesion

Epoxy resins are essential polymeric materials for various industrial applications owing to their excellent adhesion, thermal properties, and processability. Reported improvement methods for overcoming the limitations of epoxy-resin adhesives involve incorporating fillers such as silica, clay, carbon nanotubes, and graphene. While silica nanoparticles are commonly used in industrial applications, their properties often require enhancement. In this study, mesoporous silica nanoparticles (MSNs) were synthesized using cetyltrimethylammonium bromide and novel swelling agents, 2,6-dihydroxybenzoic acid and decane, to control pore sizes within the 2–4 nm range. Transmission electron microscope and nitrogen adsorption analyses confirmed pore sizes of 2.0, 3.1, and 3.9 nm. Applying MSNs as nanofillers to epoxy resin adhesive resulted in enhanced adhesive properties with increasing pore size, particularly with 0.5 wt% MSN-4 nm, achieving a 51.4 % improvement in shear strength compared to that of bare epoxy resin. This enhancement is attributed to the increased specific surface area of the MSNs, providing more interaction sites with the epoxy resin and improving resin penetration and interaction. These findings highlight the critical role of nanopore size in optimizing adhesion in nanofiller applications and emphasize the potential of MSNs as superior nanofillers for future industrial applications.

Effects of Hf addition on the microstructure and properties of Cu-Sn-P alloy

In this paper, the effects of Hf addition on the mechanical properties, electrical conductivity and microstructure of Cu-Sn-P alloy were investigated. The results show that the Hf addition can enhance the mechanical properties and electrical conductivity of Cu-Sn-P alloy. The alloy with 0.05 wt.% Hf exhibits the best comprehensive performance with yield strength of 625 MPa, tensile strength of 661 MPa and electrical conductivity of 16.8 %IACS. Compared with the Cu-Sn-P alloy without Hf addition, the yield strength and tensile strength are increased by 8.4% and 7.8%, and the electrical conductivity is increased by 24.4%. The increase in the strength of Hf-added alloy can be attributed to the synergistic effect of multiple strengthening mechanisms, including fine grain strengthening, twin strengthening, dislocation strengthening, precipitation strengthening and Σ3n (n = 1, 2, 3) grain boundary strengthening. Moreover, the Hf-P precipitates can be observed in the Hf-added alloy. According to the amount of Hf addition, these precipitates can manifest as the fine HfP2 phase and the coarse HfP phase. The formation of Hf-P precipitates contributes to the precipitation strengthening and the purification of Cu matrix, thus contributing to the improvement of strength and conductivity.

Investigation of strength, durability, and microstructure properties of concrete with waste marble powder as a partial replacement of cement

Purpose Cement plays a significant part in concrete, and with the increasing demand for concrete, cement output varies day by day, allowing production to carbon dioxide emissions. As well as marble processing creates stone slurry and solid discards. These are often dumped irresponsibly on open land, polluting the soil. This improper disposal of marble waste is a major environmental concern. This study aims to propose a sustainable solution for reusing this waste material as a concrete additive. Design/methodology/approach A total of 135 concrete cubes of size 150 × 150 × 150 mm, 54 concrete cylinders of size 150 mm dia. and 300 mm height and 54 concrete beams of size 150 × 150 × 700 mm were cast. The replacement was 0%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5% and 20% by weight of cement with marble dust to create M30 concrete with a water-cement ratio of 0.45. The test was performed to find the compressive strength (CS), flexural strength (FS) and split tensile strength. Also, durability tests like rapid chloride penetration test (RCPT), acid attack, ultrasonic pulse velocity (UPV) and water permeability test were performed. Findings After 7 and 28 days of curing, it was found that replacing 5% of cement with marble powder led to an initial strength improvement of up to 25% for both curing periods. However, further increases in marble dust resulted in an inconsistent decrease in strength for all the mixtures. Also, durability properties like acid attack test, water permeability test and RCPT, showed good performance at the optimum percentage of waste marble powder (WMP) as cement replacement. The microscopic analysis revealed a denser pore structure at lower WMP replacement levels, likely due to the powder filling in gaps. Originality/value This study reveals that by substituting 5% (optimum) of cement with WMP, there was CS improvement up to 8.4% and 17% for both 7 and 28 days of curing. WMP is typically finer than cement particles and fills the voids in the concrete more effectively, resulting best performance at optimum percentage against RCPT, UPV, acid attack and water permeability.

Outcomes of dual-mobility trapeziometacarpal arthroplasties: a systematic review.

This systematic review reports the clinical, patient-reported, radiographic outcomes, complications and survivorship of dual-mobility trapeziometacarpal (TMC) joint arthroplasties including the MAÏA®, Moovis® and Touch® prostheses. Thirteen studies were included and outcomes reported for 1421 such arthroplasties. Overall, improvements in strength, range of motion, pain, function and satisfaction were demonstrated with a complication incidence of 13%. The risk of dislocation was 0.6%. The follow-up period was not long enough to draw conclusions about the long-term survival of the implants. Also, due to the low quality of the evidence, it was not possible to conclude that dual-mobility TMC arthroplasty was superior to trapeziectomy. This review highlights the need for Level I evidence with adequate long-term follow-up for TMC joint arthroplasty.

Improving the distribution system capability by incorporating ZnO nanoparticles into high-density polyethylene cable materials

This paper introduces a novel insulated cable designed to enhance the distribution system’s capabilities. Accordingly, high-density polyethylene loaded with varying concentrations of zinc oxide (ZnO) nanoparticles (NPs) ranging from 0.0 to 5 wt% was prepared using the melt-blending technique. Zinc oxide (NPs) is synthesized by using sol–gel technique and their microstructure was examined by X-ray diffraction. The new insulated cable, HDPE nanocomposite loaded with 1 wt% of ZnO, demonstrates a 43% reduction in the relative dielectric constant and a 16.5% improvement in breakdown strength compared to pure HDPE. The observed changes in both the dielectric constant and breakdown strength offer several advantages in electrical applications. These benefits include a decrease in feeder current at the same loading level, mitigation of inrush transients during load switching, and a reduction in earth fault current values, particularly in unearthed distribution networks with ungrounded cables. A comparative study is conducted between the conventional insulating cable based on the original material (HDPE) and the new insulated cable incorporating ZnO nanomaterial at a ratio of 1.0 wt% of the total cable mass per unit length. This comparison utilizes data from two actual medium-voltage distribution feeders. Both actual feeders are simulated using the EMTP/ATP package. The obtained results prove the efficacy of the developed material cable (polymer doped with ZnO NPs) compared to the base material. The peak and duration of inrush current can be cut to 77.3% and 67% of their original values, respectively. The earth fault current can be reduced to 56.5% in ungrounded networks, while substation current under the normal operation can be cut to 84.3% with the same load currents.

Exercise for improving bone health in patients with AIRDs: Understanding underlying biology and physiology.

Exercise has numerous health benefits in patients with autoimmune inflammatory rheumatic diseases (AIRDs). Regular physical activity can help maintain/improve bone health. The aim of the present article was to review current knowledge on the effects of exercise on bone health in patients with AIRDs, particularly in those experiencing a high corticosteroid burden. The article also aimed to discuss potential mechanisms underlying the benefits of physical activity/exercise on bone tissue. Potential explanations regarding the role of exercise on bone health in AIRDs include anti-inflammatory effects, mechanical loading, improvement in muscle strength, hormonal changes, improvement in balance, and effects on telomere erosion, deoxyribonucleic acid methylation, and gene expression. Current evidence regarding the outcomes of exercise on bone health in patients with AIRDs is predominantly derived from studies focused on rheumatoid arthritis. Expanding research to include other rheumatic conditions would enhance the overall understanding of this topic.

Application of micro and nano modifying additives in road construction materials

The need for stronger and more sustainable road infrastructure has stimulated research into innovative materials, including micro- and nano-additives, to improve the performance of asphalt and bitumen. This paper aims to summarize the advances in the application of these additives with a focus on improving mechanical, thermal, and environmental properties. The study provides a detailed review of traditional micro-additives such as elastomers and resins, as well as advanced nanomaterials including nano silica, nano clay, and carbon nanoparticles. Methods include analyzing experimental data from recent studies on bitumen modification with biopolymeric materials such as polylactic acid (PLA), which show an increase in molecular weight, softening point, and ductility. The main results show that the use of nano additives improves the durability of the road surface, increases its resistance to cracking, and increases the service life of the material under different climatic conditions. For example, roads modified with nano silica showed a 20-30% improvement in tensile strength and a 15% reduction in deformation. In addition, PLA bitumen modification increased the softening point by 10°C and improved the overall elasticity by 25%. These results emphasize the potential of micro- and nano-additives to create more durable, environmentally friendly, high-performance road materials.

In-process laser heating for mechanical strength improvement of FFF-printed PEEK

In-process laser heating for mechanical strength improvement of FFF-printed PEEK

Investigating the influence of various metakaolin combinations with different proportions of pond ash and Alccofine 1203 on ternary blended geopolymer concrete at ambient curing.

This paper explores the use of a ternary blended geopolymer concrete (TBGPC) incorporating metakaolin (MK), pond ash (PA), and Alccofine 1203 (AF). Three combinations of MK (25%, 50%, and 75%) with varying proportions of PA and AF were prepared, validating against M30 grade cement concrete (CC). TBGPC was prepared with an 8 molarity sodium hydroxide, sodium silicate to sodium hydroxide ratio of 2.0, liquid to binder ratio of 0.5, and an ambient curing mode. For CC, a water to cement ratio of 0.42 and water curing mode were adopted. The mechanical properties and durability behavior of TBGPC and CC specimens were evaluated through compressive strength, rapid chloride penetration test, permeability test, sorptivity test, and water absorption test. The M50P35A15 mix demonstrated remarkable compressive strength improvements, showing a 203% increase over the CC mix at 1day and 250% by 3days. This trend continued with a 155% increase at 7days, 68% at 28days, and 52% at 90days, consistently outperforming the CC mix. Additionally, microstructure characteristics of the M50P35A15 mix were analyzed through SEM studies, providing validation for the observed strength development. Notably, M50P35A15 mix demonstrated substantially higher early and later strength gain. This enhancement in strength was attributed to the gradual densification of the microstructure over time and the formation of additional NASH and CASH gel in M50P35A15 mix. At 28days, the M50P35A15 mix exhibited excellent durability characteristics, with a Coulomb value of 1008, permeability of 10mm, sorptivity of 0.45mm/√min × 10-4, and water absorption of 1.07%. This study demonstrates the potential of MK, PA, and AF as viable materials for sustainable geopolymer concrete, offering a low-carbon alternative to traditional cement concrete with superior strength and durability aspects.

Experimental Study on Mechanical Characteristics of Stabilized Soil with Rice Husk Carbon and Calcium Lignosulfonate

In cold regions, the extensive distribution of silt exhibits limited applicability in engineering under freeze–thaw cycles. To address this issue, this study employed rice husk carbon and calcium lignosulfonate to stabilize silt from cold areas. The mechanical properties of the stabilized silt under freeze–thaw conditions were evaluated through unconfined compressive strength tests and triaxial shear tests. Additionally, scanning electron microscopy was utilized to analyze the mechanisms behind the stabilization. Ultimately, a damage model for rice husk carbon–calcium lignosulfonate stabilized silt was constructed based on the Weibull distribution function and Lemaitre’s principle of equivalent strain. The findings indicate that as the content of rice husk carbon and calcium lignosulfonate increases, the rate of improvement in the compressive strength of the stabilized silt progressively accelerates. With an increase in the number of freeze–thaw cycles, the deviatoric stress of the stabilized soil gradually diminishes; the decline in peak deviatoric stress becomes more gradual, while the reduction in cohesion intensifies. The decrease in the angle of internal friction is relatively minor. Microscopic examinations reveal that as the number of freeze–thaw cycles increases, the soil pores tend to enlarge and multiply. The established damage model for stabilized silt under freeze–thaw cycles and applied loads demonstrates a similar pattern between the experimental and theoretical curves under four different confining pressures, reflecting an initial rapid increase followed by a steady trend. Thus, it is evident that the damage model for stabilized silt under freeze–thaw conditions outperforms traditional constitutive models, offering a more accurate depiction of the experimental variations observed.

Effects of Yi Jin Jing on enhancing muscle strength and physical performance in older individuals: a systematic review and meta-analysis

BackgroundThe aging population is rapidly increasing, leading to physical decline and higher risks of chronic diseases, including sarcopenia, which adversely affects muscle quality and strength. Yi Jin Jing (YJJ), a traditional Chinese exercise method, can enhance flexibility and strength, but evidence regarding its effectiveness in older adults is conflicting. This meta-analysis aims to systematically evaluate the effects of YJJ on muscle strength and physical performance in this demographic.MethodsWe searched seven electronic databases: China National Knowledge Infrastructure, Wanfang Data, Sinomed, Web of Science, PubMed, Cochrane Library, and EMBASE to identify randomized controlled trials (RCTs). Following PRISMA guidelines, we quantified the effects of YJJ on muscle strength (grip strength, isokinetic strength) and physical performance (chair sit-to-stand, squatting-to-standing, shoulder flexibility, sit-and-reach tests). Treatment effects were calculated using Hedges’g. The Cochrane tool assessed risk of bias, the PEDro scale evaluated methodological quality, and the GRADE method assessed evidence quality. Data analysis was conducted using Stata 17.0 software, utilizing standardized mean differences (SMD) and 95% confidence intervals (CIs).ResultsThis meta-analysis included 10 RCTs involving 590 participants. The overall risk of bias was assessed to be low. The methodological quality of these studies was generally moderate, and the quality of the main results varied from low to moderate. The findings revealed that YJJ had considerable effects on the chair sit-to-stand test (Hedges’g = 1.06), squatting-to-standing test (Hedges’g = 1.08), and small to moderate effects on handgrip strength (Hedges’g = 0.25), 60°/s extensor peak torque (Hedges’g = 0.47), 60°/s extensor average power (Hedges’g = 0.31), 60°/s extensor total work (Hedges’g = 0.29), 60°/s flexor peak torque (Hedges’g = 0.42), 60°/s flexor average power (Hedges’g = 0.37), and 180°/s extensor peak torque (Hedges’g = 0.29), and left shoulder flexibility (Hedges’g = 0.4). However, there were no significant improvement effects in 180°/s extensor average power (Hedges’g = 0.19), 180°/s extensor total work (Hedges’g = 0.11), 180°/s flexor peak torque (Hedges’g = 0.01), 180°/s flexor average power (Hedges’g = −0.08), right shoulder flexibility (Hedges’g = 0.09), and sit-and-reach test (Hedges’g = 0.15).ConclusionYJJ significantly enhances specific aspects of physical performance, particularly chair sit-to-stand and squatting-to-standing tests, while showing small and moderate improvements in handgrip strength and knee muscle strength. However, it had no significant effects on other metrics, including shoulder flexibility and sit-and-reach tests.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024530487, Registration number: CRD42024530487.

Study on Engineering Properties and Mechanism of Loess Muck Grouting Materials

Shield tunneling generates a massive amount of muck, and achieving the on-site reuse of muck is an urgent need in the field of shield tunneling. This study, based on a section of the Xianyang diversion tunnel in a loess stratum, aims to optimize the mix ratios of loess muck grouting materials to meet specific performance requirements. Laboratory tests were conducted to analyze the effects of the bentonite content and water–solid ratio on the properties of grout. The engineering properties, cost, and environmental impact of the optimized loess muck grouting materials were compared with those of traditional grouting materials. Additionally, XRD, SEM, and CT were employed to investigate the solidification mechanism of loess muck grouting materials. The results show that the bleeding rate, setting time, fluidity, and consistency of loess muck grouting materials decreased with increasing bentonite content, while these properties increased as the water–solid ratio rose. The compressive strength reached 0.26 MPa and 1.05 MPa at 3 d and 28 d, respectively. Compared to traditional grouting materials, the economic cost and carbon emissions of loess muck grouting materials were reduced by 49.46% and 37.17%, respectively. As the curing time increased, gel filling and particle agglomeration reduced the number of pores. The dense microstructure is the primary factor for the improvement of strength.

Usability evaluation of a smart upper limb rehabilitation exercise device for individuals with disabilities

User-friendly rehabilitation exercise devices can enhance health and quality of life through the convergence of information communication and medical technology. The development of rehabilitation exercise devices accessible to individuals with disabilities is important. We aimed to investigate the convenience, safety, and effectiveness of the developed rehabilitation exercise device for individuals with disabilities. A usability evaluation of the developed rehabilitation exercise device was conducted with five rehabilitation exercise experts and six athletes with disabilities using a questionnaire, the reliability of the revised questionnaire was <i>r</i>= 0.87. Qualitative analysis was conducted using semistructured interviews following the testing of the upper limb rehabilitation exercise device by the two user groups. In the usability evaluation survey of the developed rehabilitation exercise device, the results were very positive, with an overall score of 4.25 out of 5. The highest score was assigned to the convenience of the device, followed by the effectiveness of the exercise and the safety of the device. The developed rehabilitation exercise device allows for three types of strength improvement exercises, including isometric, isokinetic, and isotonic exercises, all within a single device. Given that it is constructed with a wire system, it can be adapted to various exercise methods, depending on the type of disability. The device can be used by both nondisabled and disabled individuals, allowing for various exercise methods. The evaluation results indicate that the proposed device is highly versatile and practical.

Motion-mimicking Robotic Finger Prosthesis for Burn-induced Partial Hand Amputee: A Case Report.

Burn injuries often result in severe hand complications, including joint contractures and nerve damage, sometimes leading to amputation. Despite early treatment, hypertrophic scarring frequently hampers hand function recovery, and the thick raised scar blocks electromyography (EMG) sensing. A promising solution involves motion-mimicking robotic finger prostheses tailored to individual patient requirements. By utilizing the versatility of motion-capturing technology on a sound finger, a robotic finger prosthesis can mimic the movement of a sound finger simultaneously with less latency than EMG-based sensory mechanisms through hypertrophic scars. This case study evaluated the clinical efficacy of a customized three-dimensional printed robotic finger prosthesis in a 24-year-old man who sustained left second finger loss due to electrical burns. Despite undergoing reconstructive surgery, the patient struggled with manual dexterity. Following the adoption of a personalized robotic finger prosthesis with a finger motion-capturing device, significant improvements in grip strength and daily task performance were observed. This innovative approach has advantages such as customization, reduced latency time for finger movements, and affordability from low-cost manufacturing, suggesting its potential for broader adoption among burn-induced amputees.

Deformability of filament-wound GFRP tubes filled with lightweight aggregate concrete: Experimental and improved analytical studies

Previous research indicates that lightweight aggregate (LWA) concrete exhibits more brittle failure under compression than conventional normal density (ND) concrete. In contrast, angle-ply fiber-reinforced polymer (FRP) filament-wound tubes filled with ND concrete show significant improvements in strength and deformability compared to hollow tubes. This study evaluates the impact of these tubes on LWA concrete to mitigate its brittle behavior. Sixteen concrete-filled FRP filament-wound tubes (CFFTs) made of ±55° filament-wound glass FRP (GFRP) were tested under axial compression. The GFRP tube’s mechanical properties and fiber winding angle of ±55° allowed for a compressive strength enhancement factor ranging from two to five for the CFFTs compared to unconfined specimens. Results also revealed substantial nonlinearity and deformability in the LWA-CFFTs due to the angle-ply tube orientation. An iterative analytical model predicted the CFFT’s nonlinear response, validated by experimental data. The findings demonstrate that angle-ply FRP tubes effectively enhance the bearing capacity and deformability of inherently brittle unconfined LWA concrete.

Improvements in upper extremity isometric muscle strength, dexterity, and self-care independence during the sub-acute phase of stroke recovery: an observational study on the effects of intensive comprehensive rehabilitation

BackgroundStroke often impairs upper extremity motor function, with recovery in the sub-acute phase being crucial for regaining independence. This study examines changes in isometric muscle strength, dexterity, and self-care independence during this period, and evaluates the effects of a comprehensive intensive rehabilitation (COMIRESTROKE).MethodsIndividuals in sub-acute stroke recovery and age- and sex-matched controls were assessed for pre- and post-rehabilitation differences in primary outcomes (grip/pinch strength, Nine Hole Peg Test [NHPT], Action Research Arm Test [ARAT]). COMIRESTROKE’s effects on primary and secondary outcomes (National Institute of Health Stroke Scale [NIHSS], Modified Rankin Scale [MRS], Functional Independence Measure [FIM]) were evaluated. Outcomes were analyzed for dominant and non-dominant limbs, both regardless of impairment and with a focus on impaired limbs.ResultsFifty-two individuals with stroke (NIHSS 7.51 ± 5.71, age 70.25 ± 12.66 years, 21.36 ± 12.06 days post-stroke) and forty-six controls participated. At baseline, individuals with stroke showed significantly lower strength (dominant grip, key pinch, tip-tip pinch, padj < 0.05), higher NHPT scores (padj < 0.05), and lower ARAT scores (padj < 0.001). COMIRESTROKE led to improvements in dominant key pinch, non-dominant tip-tip pinch, NHPT, and both dominant and non-dominant ARAT (padj < 0.05). Notably, non-dominant key pinch improved significantly when considering only impaired hands. Pre- and post-test differences between groups were significant only for ARAT (both limbs), even after adjustment (padj < 0.05). All secondary outcomes (NIHSS, MRS, FIM) showed significant improvement post-COMIRESTROKE (padj < 0.001).ConclusionIndividuals with stroke exhibit reduced muscle strength and dexterity, impairing independence. However, comprehensive intensive rehabilitation significantly improves these functions. Data are available from the corresponding author upon request and are part of a sub-study of NCT05323916.

The Effect of Adding Banana Fibers on the Physical and Mechanical Properties of Mortar for Paving Block Applications

Paving blocks might encounter diverse environmental conditions during their lifespan. The durability of paving blocks is determined by their capacity to endure various exposure conditions. Synthetic fibers have been used in mortar and concrete to improve their properties. This research investigates the influence of including banana fiber (BF) on the physical and mechanical characteristics of mortar. Five different mortar mixes were developed, with varying amounts of BF ranging from 0 to 2% by volume. Testing included ultrasonic pulse velocity, compressive strength, flexural strength, total water absorption, and sorptivity. Specimens were cured for up to 90 days. The results indicate that using 0.5% BF resulted in an improvement in compressive and flexural strength compared to the control mix. There was an increase in total water absorption and the water absorption coefficient in the presence of fibers. There appeared to be good correlations between the compressive strength and the other properties examined.

Synergistic Reinforcing Effect of Hazelnut Shells and Hydrotalcite on Properties of Rigid Polyurethane Foam Composites

Recently, the development of composite materials from agricultural and forestry waste has become an attractive area of research. The use of bio-waste is beneficial for economic and environmental reasons, adapting it to cost effectiveness and environmental sustainability. In the presented study, the possibility of using hazelnut shell (HS) and hydrotalcite (HT) mineral filler was investigated. The effects of fillers in the amount of 10 wt.% on selected properties of polyurethane composites, such as rheological properties (dynamic viscosity, processing times), mechanical properties (compressive strength, flexural strength, hardness), insulating properties (thermal conductivity), and flame-retardant properties (e.g., ignition time, limiting oxygen index, peak heat release), were investigated. Polyurethane foams containing fillers have been shown to have better performance properties compared to unmodified polyurethane foams. For example, the addition of 10 wt% of hydrotalcite filler leads to PU composite foams with improved compression strength (improvement by ~20%), higher flexural strength (increase of ~38%), and comparable thermal conductivity (0.03055 W m–1 K–1 at 20 °C). Moreover, the incorporation of organic fillers has a positive effect on the fire resistance of PU materials. For example, the results from the cone calorimeter test showed that the incorporation of 10 wt% of hydrotalcite filler significantly reduced the peak of the heat release rate (pHRR) by ca. 30% compared with that of unmodified PU foam, and increased the value of the limiting oxygen index from 19.8% to 21.7%.

Preparation of high‐strength Si3N4 ceramics via vat photopolymerization: A bi‐phase particle size gradation strategy

AbstractThis paper introduces an approach to preparing high‐strength Si3N4 ceramics using vat photopolymerization with a bi‐phase particle size gradation strategy. The influence of different ratios of coarse β‐Si3N4 powders (Cβ) and fine α‐Si3N4 powders (Fα) on the slurry performance, microstructure evolution, and final ceramic strength was systematically studied. It was found that an appropriate particle size gradation can significantly reduce the viscosity of the slurry. The curing depth of Si3N4 slurries decreases with increasing Fα content, while the stability increases. During sintering, dissolved Fα‐Si3N4 not only directly precipitates into small elongated β‐Si3N4 grains but also onto the neighboring Cβ‐Si3N4, promoting the development of large elongated β‐Si3N4 grains and resulting in a bimodal microstructure distribution. The highest strength of Si3N4 ceramics was achieved with a ratio of 6:4 Cβ to Fα Si3N4 powders. Under these conditions, the Si3N4 ceramics exhibited a flexural strength of 472 MPa, significantly higher than that of Si3N4 ceramics prepared using pure Cβ/Fα powders. The strength improvement is primarily due to the well‐designed bi‐phase particle size gradation strategy, which optimizes slurry performance, minimizes defects that may be introduced during the green part printing process while controlling the microstructure evolution during sintering, achieves the ideal bimodal microstructure distribution. The outcomes of this research demonstrate the feasibility of using vat photopolymerization with bi‐phase particle size gradation for the preparation of high‐strength Si3N4 ceramics, which has great potential for application in the manufacturing of various ceramic products.

Analysis of Interface Bonding Mechanism of Babbit Alloy/Steel Compound Castings with Different Surface Treatments

Tin-based Babbitt alloy/steel bimetallic castings were prepared by compound casting with different coating surface modification treatment. The defects of modified coating surface are effectively controlled, while the unmodified interface has a considerable number of micropores. In consequence, the additional composite surface modifier greatly increased the integrity of the bimetal interface and led to a significant improvement of shear strength to ~55.61 MPa, in comparison to its counterpart with no surface modifier of ~7.04 MPa. Based on extensive experimental investigation and theoretical analysis, the role of coating surface modifiers in the interfacial strengthening was revealed. Meanwhile, the diffusion behavior of the bimetal interface connection was analyzed by first-principles calculations. These results will shed new light on the understanding of the liquid–solid connection of bimetallic composites and improve defect control at the interface.