While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics ...While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.展开更多
High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy re...High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy receives little attention.This paper conducts grinding simulation and surface grinding experiments on FeCoCrNi high entropy and alloys to analyze the grinding removal mechanism of the FeCoCrNi-based High entropy alloy.We also discuss the influence of grinding parameters,element types,element content and forming methods on grinding force and sub-surface plastic deformation after grinding.The simulation and experimental results show that as the increase of grinding depth,both tangential grinding force and normal grinding force increase,and the thickness of sub-surface plastic deformation layer decreases.With the increase of grinding speed,both tangential grinding force and normal grinding force decrease,and the thickness of sub-surface plastic deformation layer caused by grinding process shows a trend of gradual decrease.Under the same processing parameters,the normal grinding force is greater than the tangential grinding force.In FeCoCrNi series high entropy alloys,the grinding force and subsurface plastic deformation layer thickness of high entropy alloys increased with the addition in Ti content.The grinding force and plastic deformation formed by adding Ti element are greater than those formed by adding Al element,and High entropy alloys prepared using laser cladding method exhibit greater grinding force and plastic deformation than those prepared using selective laser melting method.The research results provide theoretical reference and experimental basis for high-quality grinding of high entropy alloys,which may be helpful for the design and manufacturing of high entropy alloy parts.展开更多
The surfaces of brittle materials are susceptible to defects such as scratches,cracks,and chipping during con-ventional grinding processes,which significantly compromise surface quality and service performance.A flexi...The surfaces of brittle materials are susceptible to defects such as scratches,cracks,and chipping during con-ventional grinding processes,which significantly compromise surface quality and service performance.A flexible ball-end body-armor-like abrasive tool(BAAT)can effectively remove micro-convex peaks from the surfaces of brittle materials by employing a high tangential grinding force and a low normal grinding force,thereby achieving nano-level surface roughness and ultra-smooth mirror finishes.However,the surface contact me-chanism,pressure distribution pattern,and grinding force behavior between BAAT and workpiece remain in-adequately understood.This study examines the mechanism of liquid film formation and the distribution pattern of elastohydrodynamic pressure in high-shear and low-pressure grinding areas,drawing on the theories of elastohydrodynamic lubrication,non-Newtonian fluid dynamics,and material mechanics.A high-shear low-pressure grinding force model,which incorporates elastohydrodynamic liquid film thickness and abrasive grain size,was developed.The effects of the main grinding parameters(normal load,spindle rotational speed,and abrasive grain size)on the tangential grinding force were investigated through the processing of lithium niobate crystals using an intelligent precision-grinding system.The experimental results indicated that the relative error between the predicted and experimental values was 10.74%,thereby confirming the accuracy of the grinding force model.This study advances the understanding of elastohydrodynamic lubrication mechanisms in abrasive machining and provides a crucial theoretical foundation for the application of flexible ball-end BAAT.展开更多
During the process of rail grinding,the local high temperature generated in the grinding contact area can affect the physical properties of the rail,thereby affecting its service performance.Therefore,studying the tem...During the process of rail grinding,the local high temperature generated in the grinding contact area can affect the physical properties of the rail,thereby affecting its service performance.Therefore,studying the temperature field of rail grinding is of great significance for improving the quality of rail grinding.In this paper,a calculation model for the grinding depth and contour of the semi elliptical contact area was established based on the contact geometry relationship between the steel rail and the abrasive belt for the first time,and the influence of grinding process parameters on the parameters of the contact area was elucidated.Combined with the characteristics of steel rail abrasive belt grinding process,a calculation model for heat flux density in the semi elliptical contact area was obtained and verified.Based on the above research results,the temperature field of the moving surface heat source with continuous action in the semi elliptical contact area is solved by discretization.Research has shown that under the set grinding process parameters,the simulation and theoretical temperature changes of the rail grinding surface in the semi elliptical contact area are similar and almost reach the maximum temperature at the same time.The relative error between the simulation and theoretical maximum temperature is 6.14%.Comparative analysis of theoretical calculations and simulation of maximum temperature under different grinding speeds shows good consistency in size and trend.The correctness of the above theoretical model has been verified through existing research results.This study proposes a new method for calculating the tem-perature field in the actual semi elliptical grinding area considering the rail profile,which has important the-oretical significance for the calculation of the temperature field and stress field in the grinding area.展开更多
The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment...The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment process was used to increase the fine-grained content and specific surface area of VTM concentrates,to strengthen the oxidation consolidation process of VTM pellets,and oxidation kinetic experiments were carried out.The results showed that the specific surface area of VTM concentrates was increased from 872 to 1457 cm^(2)/g by HPGR and then pelletising and roasting.With preheating at 1000℃ for 10 min and roasting at 1260℃ for 10 min,the strengths of preheated pellets were increased from 329 to 535 N,and the strengths of roasted pellets were increased from 1010 to 2591 N.The limiting link in the early stage of VTM pellets oxidation was the control of chemical reaction,while the limiting link in the later stage of oxidation was the mixed control of chemical reaction and gas diffusion.The activation energies of VTM pellets before and after HPGR pretreatment were 53.07 and 40.03 kJ/mol in the early stage of oxidation reaction,while the activation energies in the later stage of oxidation were 29.24 and 22.75 kJ/mol,respectively.展开更多
Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolan...Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolant to reduce friction,tool wear,and heat during cutting processes.MQL technique has witnessed significant developments in recent years,such as combining MQL with other sustainable techniques to achieve optimum results,using biodegradable lubricants,and innovations in nozzle designs and delivery methods.This review presents an in-depth analysis of machining characteristics(e.g.,cutting forces,temperature,tool wear,chip morphology and surface integrity,etc.)and sustainability characteristics(e.g.,energy consumption,carbon emissions,processing time,machining cost,etc.)of conventional MQL and hybrid MQL techniques like cryogenic MQL,Ranque-Hilsch vortex tube MQL,nanofluids MQL,hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials.Subsequently,the latest research and developments are analyzed and summarized in the field of MQL,and provide a detailed comparison between each technique,considering advantages,challenges,and limitations in practical implementation.In addition,this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs.Ultimately,the potential future aspects of MQL for research and industrial execution are discussed.展开更多
The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can caus...The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can cause changes in cutting force/heat,resulting in affecting gear machining precision.Therefore,this paper studies the effect of different process parameters on gear machining precision.A multi-objective optimization model is established for the relationship between process parameters and tooth surface deviations,tooth profile deviations,and tooth lead deviations through the cutting speed,feed rate,and cutting depth of the worm wheel gear grinding machine.The response surface method(RSM)is used for experimental design,and the corresponding experimental results and optimal process parameters are obtained.Subsequently,gray relational analysis-principal component analysis(GRA-PCA),particle swarm optimization(PSO),and genetic algorithm-particle swarm optimization(GA-PSO)methods are used to analyze the experimental results and obtain different optimal process parameters.The results show that optimal process parameters obtained by the GRA-PCA,PSO,and GA-PSO methods improve the gear machining precision.Moreover,the gear machining precision obtained by GA-PSO is superior to other methods.展开更多
Gear flank modification is essential to reduce the noise generated in the gear meshing process,improve the gear transmission performance,and reduce the meshing impact.Aiming at the problem of solving the additional mo...Gear flank modification is essential to reduce the noise generated in the gear meshing process,improve the gear transmission performance,and reduce the meshing impact.Aiming at the problem of solving the additional motions of each axis in the higher-order topology modification technique and how to accurately add the different movements expressed in the form of higher-order polynomials to the corresponding motion axes of the machine tool,a flexible higher-order gear topology modification technique based on an electronic gearbox is proposed.Firstly,a two-parameter topology gear surface equation and a grinding model of wheel grinding gears are established,and the axial feed and tangential feed are expressed in a fifth-order polynomial formula.Secondly,the polynomial coefficients are solved according to the characteristics of the point contact when grinding gears.Finally,an improved electronic gearbox model is constructed by combining the polynomial interpolation function to achieve gear topology modification.The validity and feasibility of the modification method based on the electronic gearbox are verified by experimental examples,which is of great significance for the machining of modification gears based on the continuous generative grinding method of the worm grinding wheel.展开更多
This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail conta...This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail contact parameters,an optimal design method for rail grinding target profile is proposed from wear profile measurement to grinding profile design according to the actual railway track and vehicle operating conditions.We utilized Isight to create a simulation test and developed an RBF proxy model that incorporated both mechanical and geometric aspects of wheel-rail contact.By integrating rail modeling,wheel-rail contact analysis,and multi-objective optimization,we established a rail grinding optimization model that was solved using the NSGA-II algorithm.After optimization,the study achieved a 31.863%reduction in average contact stress,a 70.5%reduction in matching wear work,and a 100.391%increase in the difference in rolling radius between the wheel and rail.展开更多
The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing indust...The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing industry has ranked first in the world in terms of energy consumption,accounting for 56%of China's total energy consumption.Its electricity consumption exceeds 50%of the total social electricity consumption,and its carbon emissions reach 1.81 billion tons,accounting for 34% of the national total.Against this backdrop,enhancing the sustainability of high-end equipment manufacturing industries represented by aerospace has become a major strategic need for China's modernization,and it also provides strong support for solving global environmental problems.展开更多
The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusio...The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusion height and random position distribution of abrasive grains on the abrasive wheel surface.This study investigated the distribution of undeformed chip thickness and grinding force considering the non-uniform characteristics of abrasive wheel in the grinding of K4002 nickel-based superalloy.First,a novel grinding force model was established through a kinematic-geometric analysis and a grain-workpiece contact analysis.Then,a series of grinding experiments were conducted for verifying the model.The results indicate that the distribution of undeformed chip thickness is highly consistent with the Gaussian distribution formula.The increase in the grinding depth mainly leads to an increase in the average value of Gaussian distribution.On the contrary,the increase in the workpiece infeed speed or the decrease in the grinding speed mainly increases the standard deviation of Gaussian distribution.The average and maximum errors of the grinding force model are 4.9%and 14.6%respectively,indicating that the model is of high predication accuracy.展开更多
Microgrinding is widely used in clinical bone surgery,but saline spray cooling faces technical challenges such as low wettability at the microgrinding tool–bone interface,easy clogging of the microgrinding tools,and ...Microgrinding is widely used in clinical bone surgery,but saline spray cooling faces technical challenges such as low wettability at the microgrinding tool–bone interface,easy clogging of the microgrinding tools,and high grinding temperatures.These issues can lead to bone necrosis,irreversible thermal damage to nerves,or even surgical failure.Inspired by the water-trapping and directional transportation abilities of desert beetles,this study proposes a biomimetic desert beetle microgrinding tool.The flow-field distribution directly influences the convective heat transfer of the cooling medium in the grinding zone,which in turn affects the grinding temperature.To address this,a mathematical model of the two-phase flow field at the biomimetic microgrinding tool–bone interface is developed.The results indicate an average error of 14.74%between the calculated and experimentally obtained airflow field velocities.Next,a biomimetic desert beetle microgrinding tool is prepared.Experiments with physiological saline spray cooling were conducted on fresh bovine femur bone,which has mechanical properties similar to human bone.Results show that,compared with conventional microgrinding tools,the biomimetic tools reduced bone surface temperature by 21.7%,13.2%,5.8%,20.3%,and 25.8%at particle sizes of 150#,200#,240#,270#,and 300#,respectively.The surface morphology of the biomimetic microgrinding tools after grinding is observed and analyzed,revealing a maximum clogging area reduction of 23.0%,which is 6.1%,6.0%,10.0%,15.6%,and 9.5%less than that observed with conventional tools.Finally,this study unveils the dynamic mechanism of cooling medium transfer in the flow field at the biomimetic microgrinding tool–bone interface.This research provides theoretical guidance and technical support for clinical bone resection surgery.展开更多
As the manufacturing industry shifts toward environmentally sustainable practices,grinding—a high-precision pro-cessing method—is commonly used to ensure final workpiece dimensions and surface quality.The greening o...As the manufacturing industry shifts toward environmentally sustainable practices,grinding—a high-precision pro-cessing method—is commonly used to ensure final workpiece dimensions and surface quality.The greening of grind-ing processes has emerged as an important challenge for both academia and industry.Numerous studies proposing different methods for sustainable grinding have increased rapidly;however,the technical mechanisms and develop-ment trends remain unclear.This paper applies bibliometric methods to analyze relevant articles published on WOS from 2008 to 2023.Results show that China has the highest number of publications(45.38%),with research institu-tions primarily located in China,India,and Brazil.Among publishing journals,70%are classified as Q2 or above.Addi-tionally,popular authors and influential articles in this field are identified.Keyword frequency and hotspot literature analysis reveal that research focuses primarily on minimal quantity lubrication(MQL)grinding,especially using biolubricants and nanoparticles to improve grinding performance.This article reviews the mechanisms and effects of biolubricants and nanoparticles in MQL.It further examines how multi-energy field applications enhance MQL by influencing droplet atomization,wettability,and machining performance.A low-temperature field improves the heat exchange capacity of MQL droplets,while an electrostatic field enhances droplet contact angles and disper-sion.Ultrasonic energy enhances the atomization of biolubricants,and magnetic fields facilitate nanoparticle penetra-tion into the grinding zone,reducing grinding forces.Additionally,innovations in grinding wheel structures and solid lubrication grinding can reduce grinding temperatures and forces.This paper presents a comprehensive review of eco-friendly grinding development hotspots,providing technical support and theoretical guidance for academia and industry.展开更多
Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro...Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro-structure has been applied on the micro-grinding tool.A morphology modeling has been established in this study to characterize the surface of microstructured micro-grinding tool,and the grinding performance of micro-structured micro-grinding tool has been analyzed through undeformed chip thickness,abrasive edge width,and effective distance between abrasives.Then deviation analysis,path optimization and parameter optimization of microchannel array precision grinding have been finished to improve processing quality and efficiency,and the deflection angle has the most obvious effects on the rectangular slot depth,micro-structured micro-grinding tool could reduce 10%surface roughness and 20%grinding force compared to original micro-grinding tool.Finally,the microchannel array has been machined with a size deviation of 2μm and surface roughness of 0.2μm.展开更多
During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wh...During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.展开更多
SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant dispari...SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.展开更多
The use of Minimum Quantity Lubrication(MQL)with bio-lubricants has been extensively studied in aerospace sustainable manufacturing.Enhanced MQL technologies have been proposed to reduce tool wear and improve workpiec...The use of Minimum Quantity Lubrication(MQL)with bio-lubricants has been extensively studied in aerospace sustainable manufacturing.Enhanced MQL technologies have been proposed to reduce tool wear and improve workpiece surface integrity by increasing lubricant activity.However,the relationship between enhancement behavior,physicochemical properties of biolubricants,and processability remains unclear,presenting challenges for MQL technologies,particularly with difficult-to-machine materials.To address this gap,this paper provides an in-depth mechanism analysis and a comprehensive quantitative evaluation of the machinability of enhanced MQL technologies,considering chemistry,molecular dynamics,fluid dynamics,tribology,and heat transfer.Firstly,the cooling and lubrication enhancement mechanisms of nano-lubricants were systematically summarized.focusing on molecular structure.physical properties,and preparation processes.Secondly,the atomization enhancement mechanism of Electrostatic Minimum Quantity Lubrication(EMQL)was analyzed.revealing a 49%reduction in PM2.5 concentration during the atomization process compared to conventional MQL.Thirdly,the transport and infiltration enhancement mechanisms of bio-lubricants in cutting and grinding zones were summarized,incorporating electromagnetic fields and ultrasound-assisted processes.Finally,for cutting and grinding applications involving difficult-to-machine materials in aerospace,the optimized machinability of enhanced MQL technologies was concluded,showing a 50.1%increase in lubricant heat transfer coefficient and a 31.6%decrease in grinding temperature compared to standard MQL.This paper aims to help scientists understand the effective mechanisms,formulate process specifications,and identify future development trends in this technology.展开更多
The effects of calcination temperature and mechanical ball milling on the physicochemical properties of electrolytic manganese residue(EMR),mineral phase transition,pozzolanic activity,and pore structure were studied....The effects of calcination temperature and mechanical ball milling on the physicochemical properties of electrolytic manganese residue(EMR),mineral phase transition,pozzolanic activity,and pore structure were studied.The experimental results show that the strength activity index(SAI)of 20%EMR mixed mortar at 28 days is 90.54%,95.40%,and 90.73%,respectively,after pretreatment with EMR at 800℃calcined for 3,5,and 8 min.This is mainly attributed to the high temperature decomposition of gypsum dihydrate to form activated calcium oxide.In addition,high temperature and mechanical force destroys the Si-O chemical bond and promotes the formation of calcium silicate gel structure.Due to the existence of a large number of gypsum phases in EMR mixed mortar,a large number of ettringite,C-S-H,aluminosilicate,C-A-S-H,and AFm are formed,which strongly verifies the volcanic activity of EMR.The leaching test shows that high temperature calcination has a significant effect on the stabilization of NH_(3)-N.However,the curing effect of Mn^(2+)is significant only in the calcination at 1000℃,but both Mn^(2+)and NH_(3)-N in the calcined EMR are higher than the emission standard.The encapsulation effect of EMR composite mortar provided by hydration products,and the buffering capacity of the Si-Al system for solidification of heavy metals and strong alkalis are conducive to the stability of Mn^(2+)and NH_(3)-N.After the EMR mixed mortar is aged for 3 days,Mn and NH_(3)-N are completely lower than the emission standard.In general,the EMR mixed mortar can meet the requirements for green building use.展开更多
In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size...In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size.Here,for a given number of large grinding balls,the ratio of large to small ones is set to 1:2,1:3,1:4,and 1:5 by altering the number of small ones,and how this affects the morphology,structure,and electrochemical properties of ball-milled graphene nanosheets is investigated.The results show that changing the ball ratio causes distinct changes in the morphology,structure,and properties of the graphene nanosheets.Increasing the number of small(6 mm)grinding balls decreases the nanosheet grain size monotonically;meanwhile,the crystal plane spacing,defect density,and specific surface area increase and then decrease,but the graphitization degree decreases and then increases.Ball-milled samples are then used as anodes for lithium-ion batteries,and both the specific capacity and rate capability exhibit the same trend of increase and then decrease.The ball ratio of 1:3 gives the best electrochemical performance,i.e.,a reversible specific capacity of 262.09 mA·h/g at a current density of 100 mA/g,and even after 2000 cycles at 2000 mA/g,the reversible specific capacity is 87.4%of the optimal value.展开更多
基金Supported by Hunan Provincial Natural Science Foundation(Grant Nos.2023JJ60182 and 2025JJ50273)Scientific Research Fund of Hunan Provincial Education Department(Grant Nos.22B0561 and 23C0188)National Natural Science Foundation of China(Grant No.52305465).
文摘While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.
基金Supported by National Natural Science Foundation of China(Grant No.52275412)Fundamental Research Funds for the Central Universities of China(Grant No.N2403015).
文摘High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy receives little attention.This paper conducts grinding simulation and surface grinding experiments on FeCoCrNi high entropy and alloys to analyze the grinding removal mechanism of the FeCoCrNi-based High entropy alloy.We also discuss the influence of grinding parameters,element types,element content and forming methods on grinding force and sub-surface plastic deformation after grinding.The simulation and experimental results show that as the increase of grinding depth,both tangential grinding force and normal grinding force increase,and the thickness of sub-surface plastic deformation layer decreases.With the increase of grinding speed,both tangential grinding force and normal grinding force decrease,and the thickness of sub-surface plastic deformation layer caused by grinding process shows a trend of gradual decrease.Under the same processing parameters,the normal grinding force is greater than the tangential grinding force.In FeCoCrNi series high entropy alloys,the grinding force and subsurface plastic deformation layer thickness of high entropy alloys increased with the addition in Ti content.The grinding force and plastic deformation formed by adding Ti element are greater than those formed by adding Al element,and High entropy alloys prepared using laser cladding method exhibit greater grinding force and plastic deformation than those prepared using selective laser melting method.The research results provide theoretical reference and experimental basis for high-quality grinding of high entropy alloys,which may be helpful for the design and manufacturing of high entropy alloy parts.
基金Supported by National Natural Science Foundation of China(Grant Nos.52575516,51875329)Taishan Scholar Special Foundation of Shandong Province(Grant Nos.tstp20240826,tsqn201812064)+2 种基金Shandong Provincial Natural Science Foundation(Grant No.ZR2023ME112)Key Research and Development Project of the Ningxia Hui Autonomous Region(Grant No.2024BEE02019)Innovation Capacity Improvement Programme for High-tech SMEs of Shandong Province(Grant Nos.2022TSGC1333,2022TSGC1261).
文摘The surfaces of brittle materials are susceptible to defects such as scratches,cracks,and chipping during con-ventional grinding processes,which significantly compromise surface quality and service performance.A flexible ball-end body-armor-like abrasive tool(BAAT)can effectively remove micro-convex peaks from the surfaces of brittle materials by employing a high tangential grinding force and a low normal grinding force,thereby achieving nano-level surface roughness and ultra-smooth mirror finishes.However,the surface contact me-chanism,pressure distribution pattern,and grinding force behavior between BAAT and workpiece remain in-adequately understood.This study examines the mechanism of liquid film formation and the distribution pattern of elastohydrodynamic pressure in high-shear and low-pressure grinding areas,drawing on the theories of elastohydrodynamic lubrication,non-Newtonian fluid dynamics,and material mechanics.A high-shear low-pressure grinding force model,which incorporates elastohydrodynamic liquid film thickness and abrasive grain size,was developed.The effects of the main grinding parameters(normal load,spindle rotational speed,and abrasive grain size)on the tangential grinding force were investigated through the processing of lithium niobate crystals using an intelligent precision-grinding system.The experimental results indicated that the relative error between the predicted and experimental values was 10.74%,thereby confirming the accuracy of the grinding force model.This study advances the understanding of elastohydrodynamic lubrication mechanisms in abrasive machining and provides a crucial theoretical foundation for the application of flexible ball-end BAAT.
基金Supported by National Natural Science Foundation of China(Grant No.52275399).
文摘During the process of rail grinding,the local high temperature generated in the grinding contact area can affect the physical properties of the rail,thereby affecting its service performance.Therefore,studying the temperature field of rail grinding is of great significance for improving the quality of rail grinding.In this paper,a calculation model for the grinding depth and contour of the semi elliptical contact area was established based on the contact geometry relationship between the steel rail and the abrasive belt for the first time,and the influence of grinding process parameters on the parameters of the contact area was elucidated.Combined with the characteristics of steel rail abrasive belt grinding process,a calculation model for heat flux density in the semi elliptical contact area was obtained and verified.Based on the above research results,the temperature field of the moving surface heat source with continuous action in the semi elliptical contact area is solved by discretization.Research has shown that under the set grinding process parameters,the simulation and theoretical temperature changes of the rail grinding surface in the semi elliptical contact area are similar and almost reach the maximum temperature at the same time.The relative error between the simulation and theoretical maximum temperature is 6.14%.Comparative analysis of theoretical calculations and simulation of maximum temperature under different grinding speeds shows good consistency in size and trend.The correctness of the above theoretical model has been verified through existing research results.This study proposes a new method for calculating the tem-perature field in the actual semi elliptical grinding area considering the rail profile,which has important the-oretical significance for the calculation of the temperature field and stress field in the grinding area.
基金supports provided from Guangxi Science and Technology Major Project(AA24263047).
文摘The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment process was used to increase the fine-grained content and specific surface area of VTM concentrates,to strengthen the oxidation consolidation process of VTM pellets,and oxidation kinetic experiments were carried out.The results showed that the specific surface area of VTM concentrates was increased from 872 to 1457 cm^(2)/g by HPGR and then pelletising and roasting.With preheating at 1000℃ for 10 min and roasting at 1260℃ for 10 min,the strengths of preheated pellets were increased from 329 to 535 N,and the strengths of roasted pellets were increased from 1010 to 2591 N.The limiting link in the early stage of VTM pellets oxidation was the control of chemical reaction,while the limiting link in the later stage of oxidation was the mixed control of chemical reaction and gas diffusion.The activation energies of VTM pellets before and after HPGR pretreatment were 53.07 and 40.03 kJ/mol in the early stage of oxidation reaction,while the activation energies in the later stage of oxidation were 29.24 and 22.75 kJ/mol,respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415,and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-IV-002-001 and P2023-B-IV-003-001)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the National Key Laboratory of Science and Technology on Helicopter Transmission in NUAA(No.HTL-A-22G12).
文摘Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolant to reduce friction,tool wear,and heat during cutting processes.MQL technique has witnessed significant developments in recent years,such as combining MQL with other sustainable techniques to achieve optimum results,using biodegradable lubricants,and innovations in nozzle designs and delivery methods.This review presents an in-depth analysis of machining characteristics(e.g.,cutting forces,temperature,tool wear,chip morphology and surface integrity,etc.)and sustainability characteristics(e.g.,energy consumption,carbon emissions,processing time,machining cost,etc.)of conventional MQL and hybrid MQL techniques like cryogenic MQL,Ranque-Hilsch vortex tube MQL,nanofluids MQL,hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials.Subsequently,the latest research and developments are analyzed and summarized in the field of MQL,and provide a detailed comparison between each technique,considering advantages,challenges,and limitations in practical implementation.In addition,this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs.Ultimately,the potential future aspects of MQL for research and industrial execution are discussed.
基金Projects(U22B2084,52275483,52075142)supported by the National Natural Science Foundation of ChinaProject(2023ZY01050)supported by the Ministry of Industry and Information Technology High Quality Development,China。
文摘The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can cause changes in cutting force/heat,resulting in affecting gear machining precision.Therefore,this paper studies the effect of different process parameters on gear machining precision.A multi-objective optimization model is established for the relationship between process parameters and tooth surface deviations,tooth profile deviations,and tooth lead deviations through the cutting speed,feed rate,and cutting depth of the worm wheel gear grinding machine.The response surface method(RSM)is used for experimental design,and the corresponding experimental results and optimal process parameters are obtained.Subsequently,gray relational analysis-principal component analysis(GRA-PCA),particle swarm optimization(PSO),and genetic algorithm-particle swarm optimization(GA-PSO)methods are used to analyze the experimental results and obtain different optimal process parameters.The results show that optimal process parameters obtained by the GRA-PCA,PSO,and GA-PSO methods improve the gear machining precision.Moreover,the gear machining precision obtained by GA-PSO is superior to other methods.
基金Projects(52275483,52075142,U22B2084)supported by the National Natural Science Foundation of ChinaProject(JZ2023HGPA0292)supported by the Fundamental Research Funds for the Central Universities of China。
文摘Gear flank modification is essential to reduce the noise generated in the gear meshing process,improve the gear transmission performance,and reduce the meshing impact.Aiming at the problem of solving the additional motions of each axis in the higher-order topology modification technique and how to accurately add the different movements expressed in the form of higher-order polynomials to the corresponding motion axes of the machine tool,a flexible higher-order gear topology modification technique based on an electronic gearbox is proposed.Firstly,a two-parameter topology gear surface equation and a grinding model of wheel grinding gears are established,and the axial feed and tangential feed are expressed in a fifth-order polynomial formula.Secondly,the polynomial coefficients are solved according to the characteristics of the point contact when grinding gears.Finally,an improved electronic gearbox model is constructed by combining the polynomial interpolation function to achieve gear topology modification.The validity and feasibility of the modification method based on the electronic gearbox are verified by experimental examples,which is of great significance for the machining of modification gears based on the continuous generative grinding method of the worm grinding wheel.
基金Supported by Fundamental Research Funds for the Central Universities(Grant No.2019JBM050).
文摘This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail contact parameters,an optimal design method for rail grinding target profile is proposed from wear profile measurement to grinding profile design according to the actual railway track and vehicle operating conditions.We utilized Isight to create a simulation test and developed an RBF proxy model that incorporated both mechanical and geometric aspects of wheel-rail contact.By integrating rail modeling,wheel-rail contact analysis,and multi-objective optimization,we established a rail grinding optimization model that was solved using the NSGA-II algorithm.After optimization,the study achieved a 31.863%reduction in average contact stress,a 70.5%reduction in matching wear work,and a 100.391%increase in the difference in rolling radius between the wheel and rail.
基金the support of the National Natural Science Foundation of China(Nos.52205476 and 52175415)the Natural Science Foundation of Jiangsu Province(No.BK20242040)+1 种基金the Fundamental Research Funds for the Central Universities(No.NG2024008)the Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(No.1005ZAA20003-14)。
文摘The manufacturing industry is the core support for the development of the real economy.While promoting rapid economic growth,it also brings severe resource and environmental challenges.China's manufacturing industry has ranked first in the world in terms of energy consumption,accounting for 56%of China's total energy consumption.Its electricity consumption exceeds 50%of the total social electricity consumption,and its carbon emissions reach 1.81 billion tons,accounting for 34% of the national total.Against this backdrop,enhancing the sustainability of high-end equipment manufacturing industries represented by aerospace has become a major strategic need for China's modernization,and it also provides strong support for solving global environmental problems.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-Ⅳ-002-001 and P2023-B-Ⅳ-003-001)+3 种基金the Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(No.JSKL2223K01)the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the Henan Science and Technology Public Relations Project(No.212102210445).
文摘The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusion height and random position distribution of abrasive grains on the abrasive wheel surface.This study investigated the distribution of undeformed chip thickness and grinding force considering the non-uniform characteristics of abrasive wheel in the grinding of K4002 nickel-based superalloy.First,a novel grinding force model was established through a kinematic-geometric analysis and a grain-workpiece contact analysis.Then,a series of grinding experiments were conducted for verifying the model.The results indicate that the distribution of undeformed chip thickness is highly consistent with the Gaussian distribution formula.The increase in the grinding depth mainly leads to an increase in the average value of Gaussian distribution.On the contrary,the increase in the workpiece infeed speed or the decrease in the grinding speed mainly increases the standard deviation of Gaussian distribution.The average and maximum errors of the grinding force model are 4.9%and 14.6%respectively,indicating that the model is of high predication accuracy.
基金Supported by National Natural Science Foundation of China(Grant Nos.52205481,52305477)Outstanding Youth Innovation Team in Universities of Shandong Province(Grant No.2023KJ114)+2 种基金Qingdao Science and Technology Planning Park Cultivation Plan(Grant No.23-1-5-yqpy-17-qy)Young Talent of Lifting engineering for Science and Technology in Shandong(Grant No.SDAST2024QTA043)Key Lab of Industrial Fluid Energy Conservation and Pollution Control(Ministry of Education)(Grant No.CK-2024-0033)。
文摘Microgrinding is widely used in clinical bone surgery,but saline spray cooling faces technical challenges such as low wettability at the microgrinding tool–bone interface,easy clogging of the microgrinding tools,and high grinding temperatures.These issues can lead to bone necrosis,irreversible thermal damage to nerves,or even surgical failure.Inspired by the water-trapping and directional transportation abilities of desert beetles,this study proposes a biomimetic desert beetle microgrinding tool.The flow-field distribution directly influences the convective heat transfer of the cooling medium in the grinding zone,which in turn affects the grinding temperature.To address this,a mathematical model of the two-phase flow field at the biomimetic microgrinding tool–bone interface is developed.The results indicate an average error of 14.74%between the calculated and experimentally obtained airflow field velocities.Next,a biomimetic desert beetle microgrinding tool is prepared.Experiments with physiological saline spray cooling were conducted on fresh bovine femur bone,which has mechanical properties similar to human bone.Results show that,compared with conventional microgrinding tools,the biomimetic tools reduced bone surface temperature by 21.7%,13.2%,5.8%,20.3%,and 25.8%at particle sizes of 150#,200#,240#,270#,and 300#,respectively.The surface morphology of the biomimetic microgrinding tools after grinding is observed and analyzed,revealing a maximum clogging area reduction of 23.0%,which is 6.1%,6.0%,10.0%,15.6%,and 9.5%less than that observed with conventional tools.Finally,this study unveils the dynamic mechanism of cooling medium transfer in the flow field at the biomimetic microgrinding tool–bone interface.This research provides theoretical guidance and technical support for clinical bone resection surgery.
基金Supported by National Natural Science Foundation of China(Grant Nos.52375447,52305477 and 52105457)Shandong Provincial Natural Science Foundation(Grant Nos.ZR2023QE057,ZR2024QE100 and ZR2024ME255)+2 种基金Qingdao Municipal Science and Technology Planning Park Cultivation Plan(Grant No.23-1-5-yqpy-17-qy)Shandong Provincial Science and Technology SMEs Innovation Capacity Improvement Project(Grant No.2022TSGC1115)the Special Fund of Taishan Scholars。
文摘As the manufacturing industry shifts toward environmentally sustainable practices,grinding—a high-precision pro-cessing method—is commonly used to ensure final workpiece dimensions and surface quality.The greening of grind-ing processes has emerged as an important challenge for both academia and industry.Numerous studies proposing different methods for sustainable grinding have increased rapidly;however,the technical mechanisms and develop-ment trends remain unclear.This paper applies bibliometric methods to analyze relevant articles published on WOS from 2008 to 2023.Results show that China has the highest number of publications(45.38%),with research institu-tions primarily located in China,India,and Brazil.Among publishing journals,70%are classified as Q2 or above.Addi-tionally,popular authors and influential articles in this field are identified.Keyword frequency and hotspot literature analysis reveal that research focuses primarily on minimal quantity lubrication(MQL)grinding,especially using biolubricants and nanoparticles to improve grinding performance.This article reviews the mechanisms and effects of biolubricants and nanoparticles in MQL.It further examines how multi-energy field applications enhance MQL by influencing droplet atomization,wettability,and machining performance.A low-temperature field improves the heat exchange capacity of MQL droplets,while an electrostatic field enhances droplet contact angles and disper-sion.Ultrasonic energy enhances the atomization of biolubricants,and magnetic fields facilitate nanoparticle penetra-tion into the grinding zone,reducing grinding forces.Additionally,innovations in grinding wheel structures and solid lubrication grinding can reduce grinding temperatures and forces.This paper presents a comprehensive review of eco-friendly grinding development hotspots,providing technical support and theoretical guidance for academia and industry.
基金co-supported by the Enterprise Innovation and Development Joint Program of the National Natural Science Foundation of China(No.U20B2032)Open Project Funding of State Key Laboratory for High Performance Tools(GXNGJSKL-2024-08)+1 种基金Open Foundation of the State Key Laboratory of Intelligent Manufacturing Equipment and Technology(IMETKF2023005)Introduced Innovative Scientific Research Team Project of Zhongshan(the tenth batch)(CXTD2023008)。
文摘Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro-structure has been applied on the micro-grinding tool.A morphology modeling has been established in this study to characterize the surface of microstructured micro-grinding tool,and the grinding performance of micro-structured micro-grinding tool has been analyzed through undeformed chip thickness,abrasive edge width,and effective distance between abrasives.Then deviation analysis,path optimization and parameter optimization of microchannel array precision grinding have been finished to improve processing quality and efficiency,and the deflection angle has the most obvious effects on the rectangular slot depth,micro-structured micro-grinding tool could reduce 10%surface roughness and 20%grinding force compared to original micro-grinding tool.Finally,the microchannel array has been machined with a size deviation of 2μm and surface roughness of 0.2μm.
基金Supported by National Natural Science Foundation of China(Grant No.52475137)Sichuan Provincial Science and Technology Program(Grant No.2024YFHZ0280)Sichuan Provincial Nature and Science Foundation Innovation Research Group Project(Grant No.2023NSFSC1975).
文摘During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.
基金Supported by National Natural Science Foundation of China(Grant Nos.52475480,51805334)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030249,2023A1515110059)Shenzhen Science and Technology Program(Grant No.GJHZ20220913144212023).
文摘SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.
基金supported by the following organizations:the Special Fund of Taishan Scholars Project(No.tsqn202211179)the National Natural Science Foundation of China(No.52105457)+2 种基金Young Talent of Lifting engineering for Science and Technology in Shandong,China(No.SDAST2021qt12)the National Natural Science Foundation of China(No.52375447)China Postdoctoral Science Foundation Funded Project(No.2023M732826).
文摘The use of Minimum Quantity Lubrication(MQL)with bio-lubricants has been extensively studied in aerospace sustainable manufacturing.Enhanced MQL technologies have been proposed to reduce tool wear and improve workpiece surface integrity by increasing lubricant activity.However,the relationship between enhancement behavior,physicochemical properties of biolubricants,and processability remains unclear,presenting challenges for MQL technologies,particularly with difficult-to-machine materials.To address this gap,this paper provides an in-depth mechanism analysis and a comprehensive quantitative evaluation of the machinability of enhanced MQL technologies,considering chemistry,molecular dynamics,fluid dynamics,tribology,and heat transfer.Firstly,the cooling and lubrication enhancement mechanisms of nano-lubricants were systematically summarized.focusing on molecular structure.physical properties,and preparation processes.Secondly,the atomization enhancement mechanism of Electrostatic Minimum Quantity Lubrication(EMQL)was analyzed.revealing a 49%reduction in PM2.5 concentration during the atomization process compared to conventional MQL.Thirdly,the transport and infiltration enhancement mechanisms of bio-lubricants in cutting and grinding zones were summarized,incorporating electromagnetic fields and ultrasound-assisted processes.Finally,for cutting and grinding applications involving difficult-to-machine materials in aerospace,the optimized machinability of enhanced MQL technologies was concluded,showing a 50.1%increase in lubricant heat transfer coefficient and a 31.6%decrease in grinding temperature compared to standard MQL.This paper aims to help scientists understand the effective mechanisms,formulate process specifications,and identify future development trends in this technology.
基金Funded by the National Natural Science Foundation of China(No.52178216)the Gansu Provincial Science and Technology Programme(No.23JRRA813)。
文摘The effects of calcination temperature and mechanical ball milling on the physicochemical properties of electrolytic manganese residue(EMR),mineral phase transition,pozzolanic activity,and pore structure were studied.The experimental results show that the strength activity index(SAI)of 20%EMR mixed mortar at 28 days is 90.54%,95.40%,and 90.73%,respectively,after pretreatment with EMR at 800℃calcined for 3,5,and 8 min.This is mainly attributed to the high temperature decomposition of gypsum dihydrate to form activated calcium oxide.In addition,high temperature and mechanical force destroys the Si-O chemical bond and promotes the formation of calcium silicate gel structure.Due to the existence of a large number of gypsum phases in EMR mixed mortar,a large number of ettringite,C-S-H,aluminosilicate,C-A-S-H,and AFm are formed,which strongly verifies the volcanic activity of EMR.The leaching test shows that high temperature calcination has a significant effect on the stabilization of NH_(3)-N.However,the curing effect of Mn^(2+)is significant only in the calcination at 1000℃,but both Mn^(2+)and NH_(3)-N in the calcined EMR are higher than the emission standard.The encapsulation effect of EMR composite mortar provided by hydration products,and the buffering capacity of the Si-Al system for solidification of heavy metals and strong alkalis are conducive to the stability of Mn^(2+)and NH_(3)-N.After the EMR mixed mortar is aged for 3 days,Mn and NH_(3)-N are completely lower than the emission standard.In general,the EMR mixed mortar can meet the requirements for green building use.
基金supported financially by the National Natural Science Foundation of China(Grant No.12275047).
文摘In ball milling,the process parameters are decisive in influencing the quality and performance of the final ball-milled product,and crucial but often neglected is the ratio of the grinding balls in terms of their size.Here,for a given number of large grinding balls,the ratio of large to small ones is set to 1:2,1:3,1:4,and 1:5 by altering the number of small ones,and how this affects the morphology,structure,and electrochemical properties of ball-milled graphene nanosheets is investigated.The results show that changing the ball ratio causes distinct changes in the morphology,structure,and properties of the graphene nanosheets.Increasing the number of small(6 mm)grinding balls decreases the nanosheet grain size monotonically;meanwhile,the crystal plane spacing,defect density,and specific surface area increase and then decrease,but the graphitization degree decreases and then increases.Ball-milled samples are then used as anodes for lithium-ion batteries,and both the specific capacity and rate capability exhibit the same trend of increase and then decrease.The ball ratio of 1:3 gives the best electrochemical performance,i.e.,a reversible specific capacity of 262.09 mA·h/g at a current density of 100 mA/g,and even after 2000 cycles at 2000 mA/g,the reversible specific capacity is 87.4%of the optimal value.
