Owing to the presence of large residual internal stress during cold compaction,it is difficult to optimize the multiple high-frequency magnetic properties of amorphous soft magnetic composites(ASMCs)simultaneously.Her...Owing to the presence of large residual internal stress during cold compaction,it is difficult to optimize the multiple high-frequency magnetic properties of amorphous soft magnetic composites(ASMCs)simultaneously.Here,a surface nanoengineering strategy was proposed to address the above dilemma by constructing a stress buffer layer composed of amorphous nano-particles,between amorphous powder and insulation coating.The amorphous FeSiBCCr@x wt.%FeB(x=0.5,1,3)composite powders with coreshell structures were successfully prepared via an in-situ chemical reduction method.Especially,when the composite ratio of nano-particles is 1 wt.%,the comprehensive properties of the ASMC reach the best balance.Compared with the FeSiBCCr ASMC,the saturation magnetization of the modified ASMC enhances from 153 to 171 emu/g.Meanwhile,the core loss decreases by 28.25%,while the effective permeability increases by 25% and can stabilize to∼20 MHz.Therefore,our work provides a strategy for achieving superior comprehensive soft magnetic properties of ASMCs via surface nanoengineering,which presents enormous application potential in high-frequency electric devices.展开更多
The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the...The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the Two-Dimensional (2D) nanomaterials with unique lamellar structures and biological properties have been demonstrated to have excellent antibacterial properties. Antibacterial properties can be improved by feasible chemical strategies for preparing 2D nanomaterials coating on the surface of CFR-P. In this work, Black Phosphorus (BP) coating was prepared on the originally chemically inert CFR-P surface based on wet chemical pretreatment. The physical and chemical properties, including surface microstructure, chemical composition and state, roughness and hydrophilicity were characterized. The antibacterial ratios against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Streptococcus mutans (S. mutans) were evaluated. The results indicated that hydrophilicity of BP coating on CFR-P was significantly higher compared to that of the pure CFR-P. Wet chemical pretreatment using mixed acid reagents (concentrated sulfuric acid and concentrated nitric acid) introduced hydroxyl, carboxyl and nitro groups on CFR-P. The BP coating exhibited the antibacterial rate of over 98% against both S. aureus and E. coli. In addition, the antibacterial rate of BP coating against the main pathogenic bacteria of dental caries, Streptococcus mutans, reached 45%.展开更多
Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this chall...Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this challenge,this study introduces a novel Mg-based interpenetratingphase composite reinforced with a nickel-titanium(NiTi)scaffold featuring a triply periodic minimal surface(TPMS)configuration.By combining experimental investigations with finite element simulations,we systematically elucidate the dual impact of the scaffold’s unit cell size(a)on manufacturing viability and mechanical enhancement.To compensate for compromised infiltration dynamics induced by decreasing a,a critical permeability threshold of 1×10^(-8) m^(2) is proposed for achieving successful composite fabrication.Mechanically,reducing a strengthens the interaction between the scaffold and matrix:the TPMS-configured NiTi scaffolds improve stress transfer,deflect crack propagation,and facilitate damage delocalization,whereas the Mg matrix preserves structural integrity and enables load redistribution.Consequently,the composites significantly outperform pure Mg,and lowering a leads to more substantial enhancements in compressive strength,energy dissipation,and deformation recoverability.This study offers valuable insight into the design and fabrication of highperformance Mg-based materials for structural and biomedical applications.展开更多
Soft magnetic composites(SMCs),coated with ultrahydrophobic insulating layer,are greatly desired to enhance corrosion resistance in practical applications.However,it still lacks scheme on simultaneously achieving in-s...Soft magnetic composites(SMCs),coated with ultrahydrophobic insulating layer,are greatly desired to enhance corrosion resistance in practical applications.However,it still lacks scheme on simultaneously achieving in-situ insulating layer with ultrahydrophobicity.In this work,we design an ultrahydrophobic insulation approach through surface modification of FeSiAl by polyvinylpyrrolidone,achieving uniform Al_(2)O_(3)/CeO_(2)layers on FeSiAl.The ultrahydrophobic CeO_(2)layer significantly improves corrosion resistance of FeSiAl SMC in NaCl solution,exhibiting a high charge transfer resistance of 823 cm²even after immersion in a 5 wt.%NaCl solution for 48 h.Meanwhile,the in-situ Al_(2)O_(3)/CeO_(2)structure formed by solid-state reaction ensures effective permeability of 59 and power loss of 92 mW/cm3(50 mT/100 kHz)with cut-off frequency of 88 MHz.This study not only presents a novel solution for enhancing corrosion resistance but also offers valuable insights into the development of high-frequency FeSiAl SMCs.展开更多
Practical applications of desulfurization gypsum are limited owing to its brittleness and low strength.To overcome these challenges,researchers have developed engineered desulfurization gypsum composites(EDGCs)by inco...Practical applications of desulfurization gypsum are limited owing to its brittleness and low strength.To overcome these challenges,researchers have developed engineered desulfurization gypsum composites(EDGCs)by incorporating ultrahigh molecular weight polyethylene(UHMWPE)fiber and sulfoaluminate cement(SAC).The mix ratio was optimized using response surface methodology(RSM).Experimental testing of EDGC under compressive and tensile loads led to the creation of a regression model that investigates the influence of variables and their interactions on the material’s compressive and tensile strengths.Additionally,microscopic morphology and hydration product composition were analyzed to explore the influence mechanism.The results indicated that EDGC’s compressive strength increased by up to 38.4%owing to a decreased water-binder ratio and higher SAC content.Similarly,tensile strength increased by up to 38.6%owing to increased SAC and fiber content.Moreover,EDGC demonstrated excellent strain-hardening behavior and multiple cracking characteristics,achieving a maximum tensile strain of nearly 3%.The research findings provide valuable insights for optimizing the performance of desulfurization gypsum.展开更多
This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast ...This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast iron(CI)filler particles.Hybrid G-E composite with added cast iron(CI)filler particles enhances stiffness,strength,and vibration damping,offering enhanced performance for vibration-sensitive engineering applications.Unlike conventional approaches,this work simultaneously employs Artificial Neural Networks(ANN)for highaccuracy property prediction and Response Surface Methodology(RSM)for in-depth analysis of factor interactions and optimization.A total of 24 experimental test data sets of varying input factors(granite weight%,epoxy weight%,and CI filler weight%)were utilized to train and test the prediction models using an ANN approach and further analyze the interaction effects using RSM.Mechanical properties,including tensile,compressive,and flexural strength,elastic modulus,density and damping properties measured under various testing conditions,were set as output parameters for prediction.This study analyzed and optimized the performance of the ANN model using Bayesian Regularization and Levenberg-Marquardt algorithms to identify the best performing number of neurons in the hidden layer for achieving the highest prediction accuracy.The proposed ANN framework achieved an exceptional average determination coefficient(R2)exceeding 99%,with Bayesian Regularization demonstrating remarkable stability in the 22-neuron range and minimal variation across all properties.RSM and ANN form a powerful framework for predicting and optimizing hybrid G-E composite properties,enabling efficient design for vibration-critical applications with reduced experimental effort and performance optimization.展开更多
The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical ...The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait.The results reveal that the MS can be divided into three distinct geochemical provinces.ProvinceⅠ,located in the central region of the strait,is characterized by residual deposits.The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions.ProvinceⅡ,situated to the north of ProvinceⅠ,exhibits provenance differences between its southern and northern regions.The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea,whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of ProvinceⅡ.ProvinceⅢextends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf,while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible.River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents,which also facilitate the transportation of Sunda Shelf sediments within the strait,while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period.The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait.This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region.展开更多
The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer （GFRP） composites. The experiments were conducted bas...The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer （GFRP） composites. The experiments were conducted based on Taguchi＇s experimental design technique. Response surface methodology and analysis of variance （ANOVA） were used to evaluate the composite machining process to perform the optimization. The results revealed that the feed rate was main influencing parameter on the surface roughness. The surface roughness increased with increasing the feed rate but decreased with increasing the cutting speed. Among the other parameters, depth of cut was more insensitive. The predicted values and measured values were fairly close to each other, which indicates that the developed model can be effectively used to predict the surface roughness on the machining of GFRP composites with 95% confidence intervals. Using such model could remarkablely save the time and cost.展开更多
The alumina toughened zirconia(ATZ) ceramic particle reinforced gray iron matrix surface composite was successfully manufactured by pressureless infi ltration. The porous preform played a key role in the infi ltrating...The alumina toughened zirconia(ATZ) ceramic particle reinforced gray iron matrix surface composite was successfully manufactured by pressureless infi ltration. The porous preform played a key role in the infi ltrating progress. The microstructure was observed by scanning electron microscopy(SEM); the phase constitutions was analyzed by X-ray diffraction(XRD); and the hardness and wear resistance of selected specimens were tested by hardness testing machine and abrasion testing machine, respectively. The addition of high carbon ferrochromium powders leads to the formation of white iron during solidifi cation. The wear volume loss rates of ATZ ceramic particle reinforced gray iron matrix surface composite decreases fi rst, and then tends to be stable. The wear resistance of the composite is 2.7 times higher than that of gray iron matrix. The reason is a combination of the surface hardness increase of gray iron matrix and ATZ ceramic particles and alloy carbides protecting effect on gray iron matrix.展开更多
In the present work, the surface characteristics of Electrical Discharge Machined (EDM) Al (6351)eSiC and Al (6351)eSiCeB4C composites are investigated. The composites are prepared by employing the conventional stir c...In the present work, the surface characteristics of Electrical Discharge Machined (EDM) Al (6351)eSiC and Al (6351)eSiCeB4C composites are investigated. The composites are prepared by employing the conventional stir casting technique, as it can produce better particle dispersion in the matrix. The detailed experimental study is performed on the composites by varying current (I), duty factor (t), pulse on time (Ton), and the gap voltage (V) in order to analyze the Heat Affected Zone (HAZ) formed in the sub surface and the average crater diameter formed on the machined surface of the composites as an output function. The formation of recast layers, presence of bubbles and the surface texture of the composites at various machining conditions are observed. The results show that the increased Metal Removal Rate (MRR) increases the depth of HAZ and the average crater diameter on the machined area. Further, the addition of B4C particles to the composite produces more surface defect than the AleSiC composite.展开更多
Al-matrix composites reinforced with 56.5 vol% SiC were prepared by powder metallurgy with different amounts of additives and surface modifications of SiCp. The crystalline phase, morphology, elements on the surface o...Al-matrix composites reinforced with 56.5 vol% SiC were prepared by powder metallurgy with different amounts of additives and surface modifications of SiCp. The crystalline phase, morphology, elements on the surface of SiCp and the interface between SiCp and Al were characterized by XRD, SEM, EDS and EPMA. The results show that it is favorable for the reaction between TiO2-C on the surface of SiCp and Al at the SiCp-Al interface at 1 050 ℃. Besides, the process of Na3 AlF6 melting, dissolving and then contacting with Al2 O3 formed the NaF-AlF3-Al2 O3 system, which generated OAlF2-, promoting the dessolution of Al2 O3 film on the surface of Al powder. Na3 AlF6 meets the needs of chemical reaction in TiO2-C-Al system at the SiCpAl interface in the way of offering more molten Al. After 0.75 wt% Na3 AlF6 was added into raw materials, the whole TiO2-C film and most SiO2 film were destroyed and the interfacial bonding between SiCp and Al was keeping good, in which no obvious void and crack were observed. Meanwhile, no brittle Al4 C3 phase formed in the system. At this time, the flexure strength and density of samples presented optimal values, reaching up to 106.5 MPa and 90.77% respectively.展开更多
In-situ ceramics particle reinforced aluminum matrix composites are favored in the aerospace industry due to excellent properties.However,the hard ceramic particles as the reinforcement phase bring challenges to machi...In-situ ceramics particle reinforced aluminum matrix composites are favored in the aerospace industry due to excellent properties.However,the hard ceramic particles as the reinforcement phase bring challenges to machining.To study the effect of in-situ TiB_(2)particles on machinability and surface integrity of TiB_(2)/2024 composite and TiB_(2)/7075 composite,milling experiments were performed,and compared with conventional 2024 and 7075 aluminum alloys.In-situ TiB_(2)particles clustered at the grain boundaries and dispersed inside the matrix alloy grains hinder the dislocation movement of the matrix alloy.Therefore,the milling force and temperature of the composites are higher than those of the aluminum alloys due to the increase of the strength and the decrease of the plasticity.In the milling of composites,abrasive wear is the main wear form of carbide tools,due to the scratching of hard nano-TiB_(2)particles.The composites containing in-situ TiB_(2)particles have machining defects such as smearing,micro-scratches,micro-pits and tail on the machined surface.However,in-situ TiB_(2)particles impede the plastic deformation of the composites,which greatly reduces cutting edge marks on the machined surface.Therefore,under the same milling parameters,the surface roughness of TiB_(2)/2024 composite and TiB_(2)/7075 composite is much less than that of2024 and 7075 aluminum alloy respectively.Under the milling conditions of this experiment,the machined subsurface has no metamorphic layer,and the microhardness of the machined surface is almost the same as that of the material.Besides,compared with 2024 and 7075 aluminum alloy,machined surfaces of TiB_(2)/2024 composite and TiB_(2)/7075 composite both show tensile residual stress or low magnitude of compressive residual stress.展开更多
The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with C...The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with Cu,Ni and Cu/Ni,respectively,was carried out by electroless plating method.SiCp/Al composites were prepared by hot pressed sintering followed by hot extrusion.The results show that the surface modification of SiC particles plays an effective role,which is relative to the type of surface coating,and the interfacial bonding become stronger in the following order:untreated SiCp<Ni(Cu)-coated SiCp<Ni/Cu-coated SiCp.The Ni/Cu-coated SiCp/Al composites exhibit the best comprehensive mechanical properties,with ultimate tensile strength(σUTS)and fracture strain(εf)of 389 MPa and 6.3%,respectively.Compared with that of untreated-SiCp/Al composites,theσUTS andεf are enhanced by 19.3%and 57.5%.展开更多
The mathematical models were developed to predict the ultimate tensile strength （UTS） and hardness of Al/TiB2 MMCs fabricated by in situ reaction process. The process parameters include temperature, reaction time an...The mathematical models were developed to predict the ultimate tensile strength （UTS） and hardness of Al/TiB2 MMCs fabricated by in situ reaction process. The process parameters include temperature, reaction time and mass fraction of TiB2. The in-situ casting was carried out based on three-factor five-level central composite rotatable design using response surface methodology （RSM）. The validation of the model was carried out using ANOVA. The mathematical models developed for the mechanical properties were predicted at 95% confidence limit.展开更多
For higher efficiency and precision manufacturing,more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life.At present,the in-situ TiB_2/7050 Al ...For higher efficiency and precision manufacturing,more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life.At present,the in-situ TiB_2/7050 Al metal matrix composites are widely researched due to its attractive properties such as low density,good wear resistance and improved strength.It is of great significance to investigate the machined surface roughness,residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind material.In this study,the surface roughness including two-dimensional and three-dimensional roughness,residual stress and fatigue life of milling in-situ TiB_2/7050 Al metal matrix composites were analyzed.It was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix composites.The cutting temperature played a great role on the residual stress.However,the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270°C.An exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins,river pattern veins and wave shaped veins in fracture surface.展开更多
Surface metal matrix composites(MMCs)are a group of modern engineered materials where the surface of the material is modified by dispersing secondary phase in the form of particles or fibers and the core of the materi...Surface metal matrix composites(MMCs)are a group of modern engineered materials where the surface of the material is modified by dispersing secondary phase in the form of particles or fibers and the core of the material experience no change in chemical composition and structure.The potential applications of the surface MMCs can be found in automotive,aerospace,biomedical and power industries.Recently,friction stir processing(FSP)technique has been gaining wide popularity in producing surface composites in solid state itself.Magnesium and its alloys being difficult to process metals also have been successfully processed by FSP to fabricate surface MMCs.The aim of the present paper is to provide a comprehensive summary of state-of-the-art in fabricating magnesium based composites by FSP.Influence of the secondary phase particles and grain refinement resulted from FSP on the properties of these composites is also discussed.展开更多
Alumina （Al2O3） particles reinforced copper matrix surface composites were fabricated on the bronze substrate using the vacuum infiltration casting technique. Three cases were obtained in the vacuum infiltration cas...Alumina （Al2O3） particles reinforced copper matrix surface composites were fabricated on the bronze substrate using the vacuum infiltration casting technique. Three cases were obtained in the vacuum infiltration casting technique： no infiltration, partial infiltration and full infiltration （the thickness of preforms do not exceed 3.5mm）. The reason of no infiltration is that the vacuum degree is not enough so that the force acting on the liquid metal is lower than the resistance due to the surface tension. Partial infiltration is because of somewhat lower vacuum degree and pouring temperature. Full desired infiltration is on account of suitable infiltration casting conditions, such as vacuum degree, pouring temperature, grain size and preheating temperature of the preform. The most important factor of affecting formation of surface composites is the vacuum degree, then pouring temperature and particle size. The infiltration mechanism was discussed on the bases of different processing conditions. The surface composite up to 3.5 mm in thickness with uniformly distributed Al2O3 particles could be fabricated via the vacuum infiltration casting technique.展开更多
Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing...Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field.展开更多
（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforc...（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.展开更多
The effects of Ag on the microstructure, mechanical properties, and electrical conductivity of AA2024 aluminum alloy coating were investigated. It was fabricated by friction surfacing as an additive manufacturing proc...The effects of Ag on the microstructure, mechanical properties, and electrical conductivity of AA2024 aluminum alloy coating were investigated. It was fabricated by friction surfacing as an additive manufacturing process. To carry out this investigation, Ag was added by 5.3, 10.6, and 16.0 wt.% to an AA2024 consumable rod by inserting holes in it. It was found that due to the strengthening by solid solution and the formation of precipitates and intermetallic containing Ag, the driving force for grain growth is reduced and consequently the grain size of the coating is decreased. After artificial aging heat treatment, the electrical conductivities of the coatings containing 0 and 16.0 wt.% Ag are increased by 4.15%(IACS) and decreased by 2.15%(IACS), respectively. While considering a linear relationship, it can be proposed that for a 1 wt.% Ag increase, the strength and hardness of the coating will be increased by 1.8% and 1.0%, respectively. It was established that the effect of Al6(Cu,Ag)Mg4 precipitate formation on strengthening is greater than that of Ag-rich intermetallic.展开更多
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research,China(No.2019B030302010)the National Natural Science Foundation of China(Nos.52071222,52301212,52101191,52192601,52192602,52192603)+1 种基金the National Key Research and Development Program of China(No.2021YFA0716302)Dongguan Key Research and Development Projects(No.20221200300062).
文摘Owing to the presence of large residual internal stress during cold compaction,it is difficult to optimize the multiple high-frequency magnetic properties of amorphous soft magnetic composites(ASMCs)simultaneously.Here,a surface nanoengineering strategy was proposed to address the above dilemma by constructing a stress buffer layer composed of amorphous nano-particles,between amorphous powder and insulation coating.The amorphous FeSiBCCr@x wt.%FeB(x=0.5,1,3)composite powders with coreshell structures were successfully prepared via an in-situ chemical reduction method.Especially,when the composite ratio of nano-particles is 1 wt.%,the comprehensive properties of the ASMC reach the best balance.Compared with the FeSiBCCr ASMC,the saturation magnetization of the modified ASMC enhances from 153 to 171 emu/g.Meanwhile,the core loss decreases by 28.25%,while the effective permeability increases by 25% and can stabilize to∼20 MHz.Therefore,our work provides a strategy for achieving superior comprehensive soft magnetic properties of ASMCs via surface nanoengineering,which presents enormous application potential in high-frequency electric devices.
基金support of the National Natural Science Foundation of China(61971301)In part by the Central Guidance on Local Science and Technology Development Fund of Shanxi Province under Grant YDZJSX2021A018+1 种基金Shanxi Province Higher Education Science and Technology Innovation Plan Project(2022L060)the Fundamental Research Program of Shanxi Province(Nos.202203021212227,202303021212082).
文摘The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the Two-Dimensional (2D) nanomaterials with unique lamellar structures and biological properties have been demonstrated to have excellent antibacterial properties. Antibacterial properties can be improved by feasible chemical strategies for preparing 2D nanomaterials coating on the surface of CFR-P. In this work, Black Phosphorus (BP) coating was prepared on the originally chemically inert CFR-P surface based on wet chemical pretreatment. The physical and chemical properties, including surface microstructure, chemical composition and state, roughness and hydrophilicity were characterized. The antibacterial ratios against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Streptococcus mutans (S. mutans) were evaluated. The results indicated that hydrophilicity of BP coating on CFR-P was significantly higher compared to that of the pure CFR-P. Wet chemical pretreatment using mixed acid reagents (concentrated sulfuric acid and concentrated nitric acid) introduced hydroxyl, carboxyl and nitro groups on CFR-P. The BP coating exhibited the antibacterial rate of over 98% against both S. aureus and E. coli. In addition, the antibacterial rate of BP coating against the main pathogenic bacteria of dental caries, Streptococcus mutans, reached 45%.
基金supported by the Mainland-Hong Kong Joint Funding Scheme(MHKJFS)(Project No:MHP/040/22)RGC Theme-based Research Scheme AoE/M-402/20+1 种基金National Natural Science Foundation of China/Hong Kong Research Grants Council Joint Research Scheme(Project No:N_CityU151/23)Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Materials Engineering Research Center.
文摘Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this challenge,this study introduces a novel Mg-based interpenetratingphase composite reinforced with a nickel-titanium(NiTi)scaffold featuring a triply periodic minimal surface(TPMS)configuration.By combining experimental investigations with finite element simulations,we systematically elucidate the dual impact of the scaffold’s unit cell size(a)on manufacturing viability and mechanical enhancement.To compensate for compromised infiltration dynamics induced by decreasing a,a critical permeability threshold of 1×10^(-8) m^(2) is proposed for achieving successful composite fabrication.Mechanically,reducing a strengthens the interaction between the scaffold and matrix:the TPMS-configured NiTi scaffolds improve stress transfer,deflect crack propagation,and facilitate damage delocalization,whereas the Mg matrix preserves structural integrity and enables load redistribution.Consequently,the composites significantly outperform pure Mg,and lowering a leads to more substantial enhancements in compressive strength,energy dissipation,and deformation recoverability.This study offers valuable insight into the design and fabrication of highperformance Mg-based materials for structural and biomedical applications.
基金supported by the National Science Fund for Distinguished Young Scholars(No.52225312)Zhejiang Provincial Natural Science Foundation of China(No.LMS25E010004)the National Natural Science Foundation of China(Nos.52271173 and 52377022).
文摘Soft magnetic composites(SMCs),coated with ultrahydrophobic insulating layer,are greatly desired to enhance corrosion resistance in practical applications.However,it still lacks scheme on simultaneously achieving in-situ insulating layer with ultrahydrophobicity.In this work,we design an ultrahydrophobic insulation approach through surface modification of FeSiAl by polyvinylpyrrolidone,achieving uniform Al_(2)O_(3)/CeO_(2)layers on FeSiAl.The ultrahydrophobic CeO_(2)layer significantly improves corrosion resistance of FeSiAl SMC in NaCl solution,exhibiting a high charge transfer resistance of 823 cm²even after immersion in a 5 wt.%NaCl solution for 48 h.Meanwhile,the in-situ Al_(2)O_(3)/CeO_(2)structure formed by solid-state reaction ensures effective permeability of 59 and power loss of 92 mW/cm3(50 mT/100 kHz)with cut-off frequency of 88 MHz.This study not only presents a novel solution for enhancing corrosion resistance but also offers valuable insights into the development of high-frequency FeSiAl SMCs.
基金The National Natural Science Foundation of China(No.51978504).
文摘Practical applications of desulfurization gypsum are limited owing to its brittleness and low strength.To overcome these challenges,researchers have developed engineered desulfurization gypsum composites(EDGCs)by incorporating ultrahigh molecular weight polyethylene(UHMWPE)fiber and sulfoaluminate cement(SAC).The mix ratio was optimized using response surface methodology(RSM).Experimental testing of EDGC under compressive and tensile loads led to the creation of a regression model that investigates the influence of variables and their interactions on the material’s compressive and tensile strengths.Additionally,microscopic morphology and hydration product composition were analyzed to explore the influence mechanism.The results indicated that EDGC’s compressive strength increased by up to 38.4%owing to a decreased water-binder ratio and higher SAC content.Similarly,tensile strength increased by up to 38.6%owing to increased SAC and fiber content.Moreover,EDGC demonstrated excellent strain-hardening behavior and multiple cracking characteristics,achieving a maximum tensile strain of nearly 3%.The research findings provide valuable insights for optimizing the performance of desulfurization gypsum.
文摘This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast iron(CI)filler particles.Hybrid G-E composite with added cast iron(CI)filler particles enhances stiffness,strength,and vibration damping,offering enhanced performance for vibration-sensitive engineering applications.Unlike conventional approaches,this work simultaneously employs Artificial Neural Networks(ANN)for highaccuracy property prediction and Response Surface Methodology(RSM)for in-depth analysis of factor interactions and optimization.A total of 24 experimental test data sets of varying input factors(granite weight%,epoxy weight%,and CI filler weight%)were utilized to train and test the prediction models using an ANN approach and further analyze the interaction effects using RSM.Mechanical properties,including tensile,compressive,and flexural strength,elastic modulus,density and damping properties measured under various testing conditions,were set as output parameters for prediction.This study analyzed and optimized the performance of the ANN model using Bayesian Regularization and Levenberg-Marquardt algorithms to identify the best performing number of neurons in the hidden layer for achieving the highest prediction accuracy.The proposed ANN framework achieved an exceptional average determination coefficient(R2)exceeding 99%,with Bayesian Regularization demonstrating remarkable stability in the 22-neuron range and minimal variation across all properties.RSM and ANN form a powerful framework for predicting and optimizing hybrid G-E composite properties,enabling efficient design for vibration-critical applications with reduced experimental effort and performance optimization.
基金the National Natural Science Foundation of China(Nos.42206076,42476078)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-SCSCJB01)the China-Malaysia Cooperation Project‘Effect on variability of seasonal monsoon on sedimentary process in Peninsular Malaysia waters’。
文摘The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait.The results reveal that the MS can be divided into three distinct geochemical provinces.ProvinceⅠ,located in the central region of the strait,is characterized by residual deposits.The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions.ProvinceⅡ,situated to the north of ProvinceⅠ,exhibits provenance differences between its southern and northern regions.The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea,whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of ProvinceⅡ.ProvinceⅢextends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf,while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible.River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents,which also facilitate the transportation of Sunda Shelf sediments within the strait,while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period.The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait.This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region.
文摘The present investigation focuses on the parametric influence of machining parameters on the surface finish obtained in turning of glass fiber reinforced polymer （GFRP） composites. The experiments were conducted based on Taguchi＇s experimental design technique. Response surface methodology and analysis of variance （ANOVA） were used to evaluate the composite machining process to perform the optimization. The results revealed that the feed rate was main influencing parameter on the surface roughness. The surface roughness increased with increasing the feed rate but decreased with increasing the cutting speed. Among the other parameters, depth of cut was more insensitive. The predicted values and measured values were fairly close to each other, which indicates that the developed model can be effectively used to predict the surface roughness on the machining of GFRP composites with 95% confidence intervals. Using such model could remarkablely save the time and cost.
基金financially supported by the Scientific Research Fund of Si Chuan Provincial Education Department(No.17ZA0395)the Doctoral Program Foundation of Southwest University of Science and Technology(No.10zx7113)
文摘The alumina toughened zirconia(ATZ) ceramic particle reinforced gray iron matrix surface composite was successfully manufactured by pressureless infi ltration. The porous preform played a key role in the infi ltrating progress. The microstructure was observed by scanning electron microscopy(SEM); the phase constitutions was analyzed by X-ray diffraction(XRD); and the hardness and wear resistance of selected specimens were tested by hardness testing machine and abrasion testing machine, respectively. The addition of high carbon ferrochromium powders leads to the formation of white iron during solidifi cation. The wear volume loss rates of ATZ ceramic particle reinforced gray iron matrix surface composite decreases fi rst, and then tends to be stable. The wear resistance of the composite is 2.7 times higher than that of gray iron matrix. The reason is a combination of the surface hardness increase of gray iron matrix and ATZ ceramic particles and alloy carbides protecting effect on gray iron matrix.
文摘In the present work, the surface characteristics of Electrical Discharge Machined (EDM) Al (6351)eSiC and Al (6351)eSiCeB4C composites are investigated. The composites are prepared by employing the conventional stir casting technique, as it can produce better particle dispersion in the matrix. The detailed experimental study is performed on the composites by varying current (I), duty factor (t), pulse on time (Ton), and the gap voltage (V) in order to analyze the Heat Affected Zone (HAZ) formed in the sub surface and the average crater diameter formed on the machined surface of the composites as an output function. The formation of recast layers, presence of bubbles and the surface texture of the composites at various machining conditions are observed. The results show that the increased Metal Removal Rate (MRR) increases the depth of HAZ and the average crater diameter on the machined area. Further, the addition of B4C particles to the composite produces more surface defect than the AleSiC composite.
文摘Al-matrix composites reinforced with 56.5 vol% SiC were prepared by powder metallurgy with different amounts of additives and surface modifications of SiCp. The crystalline phase, morphology, elements on the surface of SiCp and the interface between SiCp and Al were characterized by XRD, SEM, EDS and EPMA. The results show that it is favorable for the reaction between TiO2-C on the surface of SiCp and Al at the SiCp-Al interface at 1 050 ℃. Besides, the process of Na3 AlF6 melting, dissolving and then contacting with Al2 O3 formed the NaF-AlF3-Al2 O3 system, which generated OAlF2-, promoting the dessolution of Al2 O3 film on the surface of Al powder. Na3 AlF6 meets the needs of chemical reaction in TiO2-C-Al system at the SiCpAl interface in the way of offering more molten Al. After 0.75 wt% Na3 AlF6 was added into raw materials, the whole TiO2-C film and most SiO2 film were destroyed and the interfacial bonding between SiCp and Al was keeping good, in which no obvious void and crack were observed. Meanwhile, no brittle Al4 C3 phase formed in the system. At this time, the flexure strength and density of samples presented optimal values, reaching up to 106.5 MPa and 90.77% respectively.
基金the National Natural Science Foundation of China(No.51875356)。
文摘In-situ ceramics particle reinforced aluminum matrix composites are favored in the aerospace industry due to excellent properties.However,the hard ceramic particles as the reinforcement phase bring challenges to machining.To study the effect of in-situ TiB_(2)particles on machinability and surface integrity of TiB_(2)/2024 composite and TiB_(2)/7075 composite,milling experiments were performed,and compared with conventional 2024 and 7075 aluminum alloys.In-situ TiB_(2)particles clustered at the grain boundaries and dispersed inside the matrix alloy grains hinder the dislocation movement of the matrix alloy.Therefore,the milling force and temperature of the composites are higher than those of the aluminum alloys due to the increase of the strength and the decrease of the plasticity.In the milling of composites,abrasive wear is the main wear form of carbide tools,due to the scratching of hard nano-TiB_(2)particles.The composites containing in-situ TiB_(2)particles have machining defects such as smearing,micro-scratches,micro-pits and tail on the machined surface.However,in-situ TiB_(2)particles impede the plastic deformation of the composites,which greatly reduces cutting edge marks on the machined surface.Therefore,under the same milling parameters,the surface roughness of TiB_(2)/2024 composite and TiB_(2)/7075 composite is much less than that of2024 and 7075 aluminum alloy respectively.Under the milling conditions of this experiment,the machined subsurface has no metamorphic layer,and the microhardness of the machined surface is almost the same as that of the material.Besides,compared with 2024 and 7075 aluminum alloy,machined surfaces of TiB_(2)/2024 composite and TiB_(2)/7075 composite both show tensile residual stress or low magnitude of compressive residual stress.
基金Project(2017zzts111)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The effects of SiCp surface modifications(Cu coating,Ni coating and Ni/Cu coating)on the microstructures and mechanical properties of Al matrix composites were investigated.Surface modification of SiC particles with Cu,Ni and Cu/Ni,respectively,was carried out by electroless plating method.SiCp/Al composites were prepared by hot pressed sintering followed by hot extrusion.The results show that the surface modification of SiC particles plays an effective role,which is relative to the type of surface coating,and the interfacial bonding become stronger in the following order:untreated SiCp<Ni(Cu)-coated SiCp<Ni/Cu-coated SiCp.The Ni/Cu-coated SiCp/Al composites exhibit the best comprehensive mechanical properties,with ultimate tensile strength(σUTS)and fracture strain(εf)of 389 MPa and 6.3%,respectively.Compared with that of untreated-SiCp/Al composites,theσUTS andεf are enhanced by 19.3%and 57.5%.
文摘The mathematical models were developed to predict the ultimate tensile strength （UTS） and hardness of Al/TiB2 MMCs fabricated by in situ reaction process. The process parameters include temperature, reaction time and mass fraction of TiB2. The in-situ casting was carried out based on three-factor five-level central composite rotatable design using response surface methodology （RSM）. The validation of the model was carried out using ANOVA. The mathematical models developed for the mechanical properties were predicted at 95% confidence limit.
基金National Natural Science Foundation of China(No.51775443)National Science and Technology Major Project of China(No.2017-VII-00150111)。
文摘For higher efficiency and precision manufacturing,more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life.At present,the in-situ TiB_2/7050 Al metal matrix composites are widely researched due to its attractive properties such as low density,good wear resistance and improved strength.It is of great significance to investigate the machined surface roughness,residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind material.In this study,the surface roughness including two-dimensional and three-dimensional roughness,residual stress and fatigue life of milling in-situ TiB_2/7050 Al metal matrix composites were analyzed.It was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix composites.The cutting temperature played a great role on the residual stress.However,the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270°C.An exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins,river pattern veins and wave shaped veins in fracture surface.
文摘Surface metal matrix composites(MMCs)are a group of modern engineered materials where the surface of the material is modified by dispersing secondary phase in the form of particles or fibers and the core of the material experience no change in chemical composition and structure.The potential applications of the surface MMCs can be found in automotive,aerospace,biomedical and power industries.Recently,friction stir processing(FSP)technique has been gaining wide popularity in producing surface composites in solid state itself.Magnesium and its alloys being difficult to process metals also have been successfully processed by FSP to fabricate surface MMCs.The aim of the present paper is to provide a comprehensive summary of state-of-the-art in fabricating magnesium based composites by FSP.Influence of the secondary phase particles and grain refinement resulted from FSP on the properties of these composites is also discussed.
基金This work was financially supported by the National Natural Science Foundation of Gansu Province (No.ZS021-A25-024-C), theChun-Hui Plan of the Ministry of Education of China (Z2004-1-62013) and the Young Teacher Startup Foundation Project of Lanz-hou University of Technology
文摘Alumina （Al2O3） particles reinforced copper matrix surface composites were fabricated on the bronze substrate using the vacuum infiltration casting technique. Three cases were obtained in the vacuum infiltration casting technique： no infiltration, partial infiltration and full infiltration （the thickness of preforms do not exceed 3.5mm）. The reason of no infiltration is that the vacuum degree is not enough so that the force acting on the liquid metal is lower than the resistance due to the surface tension. Partial infiltration is because of somewhat lower vacuum degree and pouring temperature. Full desired infiltration is on account of suitable infiltration casting conditions, such as vacuum degree, pouring temperature, grain size and preheating temperature of the preform. The most important factor of affecting formation of surface composites is the vacuum degree, then pouring temperature and particle size. The infiltration mechanism was discussed on the bases of different processing conditions. The surface composite up to 3.5 mm in thickness with uniformly distributed Al2O3 particles could be fabricated via the vacuum infiltration casting technique.
文摘Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field.
基金co-supported by the National Natural Science Foundation of China (Nos. 51235004, 51375235)the Fundamental Research Funds for the Central Universities (No. NE2014103) of ChinaPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) of China
文摘（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.
基金funding support of Babol Noshirvani University of Technology,Iran,through Grant Program No.BNUT/370167/99。
文摘The effects of Ag on the microstructure, mechanical properties, and electrical conductivity of AA2024 aluminum alloy coating were investigated. It was fabricated by friction surfacing as an additive manufacturing process. To carry out this investigation, Ag was added by 5.3, 10.6, and 16.0 wt.% to an AA2024 consumable rod by inserting holes in it. It was found that due to the strengthening by solid solution and the formation of precipitates and intermetallic containing Ag, the driving force for grain growth is reduced and consequently the grain size of the coating is decreased. After artificial aging heat treatment, the electrical conductivities of the coatings containing 0 and 16.0 wt.% Ag are increased by 4.15%(IACS) and decreased by 2.15%(IACS), respectively. While considering a linear relationship, it can be proposed that for a 1 wt.% Ag increase, the strength and hardness of the coating will be increased by 1.8% and 1.0%, respectively. It was established that the effect of Al6(Cu,Ag)Mg4 precipitate formation on strengthening is greater than that of Ag-rich intermetallic.
