Ultra-high-strength aluminumalloy profile is an ideal choice for aerospace structuralmaterials due to its excellent specific strength and corrosion resistance.However,issues such as uneven metal flow,stress concentrat...Ultra-high-strength aluminumalloy profile is an ideal choice for aerospace structuralmaterials due to its excellent specific strength and corrosion resistance.However,issues such as uneven metal flow,stress concentration,and forming defects are prone to occur during their extrusion.This study focuses on an Al-Zn-Mg-Cu ultra-high-strength aluminum alloy profile with a double-U,multi-cavity thin-walled structure.Firstly,hot compression experiments were conducted at temperatures of 350○C,400○C,and 450○C,with strain rates of 0.01 and 1.0 s^(−1),to investigate the plastic deformation behavior of the material.Subsequently,a 3D coupled thermo-mechanical extrusion simulation model was established using Deform-3D to systematically analyze the influence of die structure and process parameters on metal flow velocity,effective stress/strain,and temperature distribution.The simulation revealed significant velocity differences,stress concentration,and uneven temperature distribution.Key parameters,including mesh density,extrusion ratio,die fillet,and bearing length,were optimized through full-factorial experiments.This optimization,combined with a stepped flow-guiding die design,effectively improved the metal flow pattern during extrusion.Trial production based on both the initial and optimized parameters were carried out.A comparative analysis demonstrates that the optimized scheme results in a final profile whose cross-section matches the target design closely,with complete filling of complex features and no obvious forming defects.This research provides a valuable reference for the extrusion process optimization and die design of complex-section profiles made from ultra-high-strength aluminum alloys.展开更多
The microstructure and mechanical properties of ZK60 extruded alloy by rapid solidification(RS)and as-cast ingot processes were investigated using optical microscope,scanning electron microscope,X-ray diffraction,elec...The microstructure and mechanical properties of ZK60 extruded alloy by rapid solidification(RS)and as-cast ingot processes were investigated using optical microscope,scanning electron microscope,X-ray diffraction,electron back-scatter diffraction,and mechanical tests.The results show that the RS ZK60 extruded alloy exhibits relatively high tensile yield strength(TYS),compressive yield strength(CYS)and elongation of 300.8 MPa,303.6 MPa and 18.6%,respectively.The RS ZK60 extruded alloy with an ultra-fine grain size of 1.28μm not only has a weak texture with a maximum polar density of 3.3 but also addresses the tension-compression asymmetry with a CYS/TYS ratio of approximately 1.0.The calculation of the strengthening mechanism indicates that the improvement in the mechanical properties of the RS ZK60 extruded alloy is primarily attributed to grain refinement.展开更多
A comparative analysis was performed on poly(lactic acid)(PLA),poly(caprolactone)(PCL),basalt fiber(BF)composites produced using two distinct approaches:direct blending and masterbatching.The limitations of PLA-BF com...A comparative analysis was performed on poly(lactic acid)(PLA),poly(caprolactone)(PCL),basalt fiber(BF)composites produced using two distinct approaches:direct blending and masterbatching.The limitations of PLA-BF composites with regard to distribution and adhesion are well-documented,as are chemical treatment methods(addition of compatibilisers,surface treatments,silanization).This work aimed to study an industrially relevant potential solution of utilising a PCL-BF masterbatch,prepared as a 50/50 wt.%blend using planetary roller extrusion(PEX)to both improve the distribution and homogeneity of the fibers as well as provide a secondary adhesion site to facilitate improved mechanical properties of the final PLA-PCL-BF composite.The resultant materials were injection moulded to prepare ISO standard test specimens and tested on the basis of their physical properties via tensile testing,impact strength testing,flexural analysis,Fourier transforminfrared spectroscopy and water absorption capability.The results displayed that the incorporation of PCL and BF led to an increase in ductility of the composite materials,allowing for improvements in the inherent brittleness of virgin PLA.Major increases in the impact strength were achieved with the utilisation of a 25% PCL/BF masterbatch,allowing for a greater than 50%increase.As an overall observation,the use of a masterbatching process,opposed to direct blending of the constituent materials allows for a greater consistency of composite to be achieved at the expense of increased gains.展开更多
To investigate the effects of extrusion temperature on the microstructure and mechanical properties of WE43 magnesium alloy,extrusion experiments were conducted under 330,380,430,and 450℃,and the extrusion ratio was ...To investigate the effects of extrusion temperature on the microstructure and mechanical properties of WE43 magnesium alloy,extrusion experiments were conducted under 330,380,430,and 450℃,and the extrusion ratio was 16.The experimental results indicate that,at a low temperature of 330℃,the alloy precipitates a large amount of second phases rich in Zr elements.Moreover,the texture strength and kernel average misorientation value are the highest,with values of 27.77 and 0.71,respectively.The increase in extrusion temperature leads to a gradual decrease in texture strength and kernel average misorientation value.The strength of the alloy is the highest at an extrusion temperature of 330℃.Its tensile yield stress is 254.7 MPa and ultimate tensile strength is 302.7 MPa,respectively.As the extrusion temperature increases,the strength of the alloy gradually decreases.At an extrusion temperature of 450℃,the tensile yield stress is 181.3 MPa and ultimate tensile strength is 265.7 MPa,respectively.The elongation first increases and then decreases,with an elongation of 20.9%at an extrusion temperature of 330℃.At an extrusion temperature of 430℃,the elongation reaches its maximum value,which is 23.6%.At an extrusion temperature of 450℃,the elongation reaches its lowest value,which is 16.4%.展开更多
Most failures in component operation occur due to cyclic loads.Validation has been performed under quasistatic loads,but the fatigue life of components under dynamic loads should be predicted to prevent failures durin...Most failures in component operation occur due to cyclic loads.Validation has been performed under quasistatic loads,but the fatigue life of components under dynamic loads should be predicted to prevent failures during component service life.Fatigue is a damage accumulation process where loads degrade the material,depending on the characteristics and number of repetitions of the load.Studies on themechanical fatigue of 3D-printedOnyx are limited.In this paper,the strength of 3D-printed Onyx components under dynamic conditions(repetitive loads)is estimated.Fatigue life prediction is influenced bymanufacturing processes,material properties,and applied loads,which can cause scatter in the results due to the interplay of these factors.By utilizing synthetic parameters derived from mechanical properties,the accuracy of fatigue life predictions has been improved significantly,from 23.13%to 98.33%.Additive manufacturing is flexible,but this flexibility generates scatter in the mechanical properties of produced components.This work also proposes the use of synthetic data with a neural network to improve the fatigue life prediction of printedOnyx subjected to tension–tension loads.Experimental uniaxial loads were used to characterize themechanical behaviorofprinted specimens.The experimental datawereused to evaluate thenumerical predictionsobtainedthrough finite element analysis using commercial software and an artificial neural network.The results showed that the use of synthetic data helped improve fatigue life prediction.展开更多
Additive Manufacturing,also known as 3D printing,has transformed conventional manufacturing by building objects layer by layer,with material extrusion or fused deposition modeling standing out as particularly popular....Additive Manufacturing,also known as 3D printing,has transformed conventional manufacturing by building objects layer by layer,with material extrusion or fused deposition modeling standing out as particularly popular.However,due to its manufacturing process and thermal nature,internal voids and pores are formed within the thermoplastic materials being fabricated,potentially leading to a decrease in mechanical properties.This paper discussed the effect of printing parameters on the porosity and the mechanical properties of the 3D printed polylactic acid(PLA)through micro-computed tomography(microCT),computational image analysis,and Charpy impact testing.The results for both tests were correlated to investigate the relationship between porosity and Charpy impact strength.PLA samples of 1 cm^(3)×1 cm^(3)×1 cm^(3) were 3D printed at printing temperatures of 180℃,200℃,220℃,and 240℃,and at printing speeds of 50,80,and 110 mm/s,while porosity was measured frommicroCT-reconstructed data.Additionally,impact strength was assessed using a notched Charpy impact tester following ASTMD6610-18.In general,results show that higher printing temperatures and lower printing speeds reduced pore size by improving material flow and fusion,while also increasing impact strength due to better thermal bonding and interlayer adhesion.A maximum 36.8% reduction in mean pore size and a 114% improvement in impact strength were observed at 110 mm/s and 220℃.Conversely,increasing printing speed led to lowerCharpy impact strength.Optimal impact behavior andminimal voids were observed at a printing temperature of 220℃ and a printing speed of 50 mm/s.展开更多
The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process ...The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.展开更多
High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products.Unfortunately,the extrusi...High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products.Unfortunately,the extrusion process has been seen as a“black box”with limited information about what occurs inside,causing serious obstacles in developing meat substitutes.This study designed a high-moisture extrusion process and developed 10 new plant-based meat substitutes comparable to the fibrous structure of real animal meat.The study used the Feature-Augmented Principal Component Analysis(FA-PCA)method to visualize and understand the whole extrusion process in three ways systematically and accurately.It established six sets of mathematical models of the high-moisture extrusion process based on 8000 pieces of data,including five types of parameters.The FA-PCA method improved the R^(2) values significantly compared with the PCA method.The Way 3 was the best to predict product quality(Z),demonstrating that the gradually molecular conformational changes(Y^(n'))were critical in controlling the final quality of the plant-based meat substitutes.Moreover,the first visualization platform software for the high-moisture extrusion process has been established to clearly show the“black box”by combining the virtual simulation technology.Through the software,some practice work such as equipment installation,parameter adjustment,equipment disassembly,and data prediction can be easily achieved.展开更多
To fully utilize the in-situ resources on the moon to facilitate the establishment of a lunar habitat is significant to realize the long-term residence of mankind on the moon and the deep space exploration in the futu...To fully utilize the in-situ resources on the moon to facilitate the establishment of a lunar habitat is significant to realize the long-term residence of mankind on the moon and the deep space exploration in the future.Thus,intensive research works have been conducted to develop types of 3D printing approach to adapt to the extreme environment and utilize the lunar regolith for in-situ construction.However,the in-situ 3D printing using raw lunar regolith consumes extremely high energy and time.In this work,we proposed a cost-effective melting extrusion system for lunar regolith-based composite printing,and engineering thermoplastic powders are employed as a bonding agent for lunar regolith composite.The high-performance nylon and lunar regolith are uniformly pre-mixed in powder form with different weight fractions.The high-pressure extrusion system is helpful to enhance the interface affinity of polymer binders with lunar regolith as well as maximize the loading ratio of in-situ resources of lunar regolith.Mechanical properties such as tensile strength,elastic modulus,and Poisson’s ratio of the printed specimens were evaluated systematically.Especially,the impact performance was emphasized to improve the resistance of the meteorite impact on the moon.The maximum tensile strength and impact toughness reach 36.2 MPa and 5.15 kJ/m2,respectively.Highpressure melt extrusion for lunar regolith composite can increase the effective loading fraction up to 80 wt.% and relatively easily adapt to extreme conditions for in-situ manufacturing.展开更多
The samples obtained by Finite Element Method (FEM) simulation for section extrusion process have been trained on BP Neural Networks. The mapping relationsbetween die's geometrical parameters and energetic paramet...The samples obtained by Finite Element Method (FEM) simulation for section extrusion process have been trained on BP Neural Networks. The mapping relationsbetween die's geometrical parameters and energetic parameters, such as stress and strain generated in the die are established. The extrusion process model and its expert system are also determined. The excellent expansibility this system possesses provides a new prospect for the future development of expert system for section extrusion dies.展开更多
BACKGROUND Intra-gastric migration of the distal ventriculoperitoneal shunt(VPS)catheter clinically presenting with or without trans-oral extrusion is one of the rare complications of VPS catheter insertion.AIM To ide...BACKGROUND Intra-gastric migration of the distal ventriculoperitoneal shunt(VPS)catheter clinically presenting with or without trans-oral extrusion is one of the rare complications of VPS catheter insertion.AIM To identify the demographics,clinical presentation,clinical findings,and results of surgical therapy offered for the treatment of intra-gastric migration of the distal VPS catheter,clinically presented with or without trans-oral extrusion.METHODS An online search was performed for the extraction/retrieval of the published/available literature pertaining to the above-mentioned VPS complication.Manuscripts were searched from PubMed,PMC(PubMed Central),ResearchGate,and Google Scholar databases using various terminology relating to the VPS complications.The first case of migration of a VPS catheter into the stomach was reported in the year 1980,and the data were retrieved from 1980 to December 2022.Cases were categorized into two groups;Group A:Cases who had migration of the distal VPS catheter into the stomach and clinically presented with trans-oral extrusion of the same,and Group B:Cases who had migration of the distal VPS catheter into the stomach,but presented without trans-oral extrusion.RESULTS A total of n=46 cases(n=27;58.69%male,and n=19;41.3%females)were recruited for the systematic review.Group A included n=32,and Group B n=14 cases.Congenital hydrocephalus was the indication for the primary VPS insertion for approximately half of the(n=22)cases.Approximately sixty percent(n=27)of them were children≤5 years of age at the time of the diagnosis of the complication mentioned above.In seventy-two percent(n=33)cases,this complication was detected within 24 mo after the VPS insertion/last shunt revision.Clinical diagnosis was evident for the entire group A cases.Various diagnostic modalities were used to confirm the diagnosis for Group B cases.Various surgical procedures were offered for the management of the complication in n=43 cases of both Groups.In two instances,intra-gastric migration of the distal VPS catheter was detected during the autopsy.This review documented four deaths.CONCLUSION Intra-gastric migration of the peritoneal end of a VPS catheter is one of the rare complications of VPS catheter implantation done for the treatment of hydrocephalus across all age groups.It was more frequently reported in children,although also reported in adults and older people.A very high degree of clinical suspicion is required for the diagnosis of a case of an intra-gastric migration of the distal VPS catheter clinically presenting without transoral extrusion.展开更多
Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusi...Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.展开更多
Solvent evaporation method for preparation of nanomatrix has the disadvantages,such as residual organic solvent,environmental pollution,explosion-proofing and so on.To overcome these shortcomings,a series of fenofibra...Solvent evaporation method for preparation of nanomatrix has the disadvantages,such as residual organic solvent,environmental pollution,explosion-proofing and so on.To overcome these shortcomings,a series of fenofibrate nanomatrix drug delivery system(NDDS)consisting of nano-porous silica Sylysia■350(S350)and pH sensitive material Eudragit■L100-55(EL100-55)were prepared using hot-melt extrusion(HME),and their in vitro dissolution and in vivo bioavailability were compared.Finally,the formulation with the highest in vivo bioavailability was selected as the optimized formulation for DSC and PXRD characterization.The results showed that the optimized NDDS showed a higher bioavailability than the reference formulation,although there was crystalline form drug remaining in NDDS.The relative bioavailability of the optimized formulation was 157.1%compared with the commercial product Lipanthyl■.In addition,the relative bioavailability of the optimized formulation was 124.8%in comparison with the formulation prepared by solvent evaporation method,showing that the NDDS prepared by the HME method was effective in improving the bioavailability of fenofibrate.In conclusion,HME was a promising method to prepare NDDS.展开更多
Extrusion is a common process technique used to fabricate porous materials such as catalysts and membranes. The performance and efficiency of such materials are governed by porosity and pore distribution. The spatial ...Extrusion is a common process technique used to fabricate porous materials such as catalysts and membranes. The performance and efficiency of such materials are governed by porosity and pore distribution. The spatial variation of porosity within the catalyst structure can be linked to process variables in the extrusion processes such as extrusion velocity. A change in extrusion velocity can lead to a change in extrusion pressure. The extrusion pressure effect is a combination of die entry deformation and frictional die land shear. In this work, the effect of extrusion velocity on the spatial variation of porosity in a titania-binder extrudate has been studied. Capillary rheometer analysis was done to investigate the effect of extrusion velocity. A segmentation approach was developed to study the spatial variation of porosity at the die wall (sheared region) compared to the unsheared (center) region of the extrudate. The results show that the extrusion pressure effect increases as the velocity increases. The extrusion conditions affect the spatial variation of porosity.展开更多
To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,t...To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.展开更多
Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of lo...Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of low-temperature extrusion shear specimens(200℃)demonstrates the exceptional strength-ductility synergy,yield strength of 277 MPa,yield strength ratio of 0.95,and elongation of 24%.Microstructural observations reveal the mechanisms underlying its high strength-plasticity synergy at room temperature.This study investigates the effects of different temperature gradients on the microstructure by analyzing experiments conducted at three temperatures:300℃,250℃,and 200◦C.Ultimately,the formation mechanism of the bimodal microstructure obtained at 200℃ is elucidated.The distinctive crystallographic texture oriented at 34°relative to the loading axis direction effectively mitigates stress concentration by inducing the synergistic activation of multiple slip systems.Furthermore,the transition trends of different slip systems and texture evolution during tensile deformation are validated through Visco-Plastic Self-Consistent(VPSC)simulations and corroborated by microstructural analysis.With geometrically necessary dislocation(GND)density(4.28×10^(15)m^(-2))and pyramidal slip activation(~45%).This study has successfully broken through the bottleneck of strength-ductility trade-off in magnesium alloys,providing theoretical support for the development of high-reliability magnesium alloys.展开更多
Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys...Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys were analyzed by XRD,SEM,and TEM.The effects of master alloy addition and holding time on the microstructure and mechanical properties of A356 alloy were investigated.Under the optimum refiner addition of 0.3wt.%and the holding time of 20 min,the average grain size of the refined A356 alloy is 151.8±9.11μm,89.62%lower than that of original A356 alloy.The tensile strength and elongation of as-cast A356refined alloy are 196.11 MPa and 5.75%,respectively.After T6 treatment,the tensile strength and elongation of A356 refined alloy are 290.1 MPa and 3.09%,respectively.The fracture morphology is characterized by a predominance of along-crystal fracture with a small amount of through-crystal fracture,attributed to the refined grains.Finer grains promote crack path deflection and localized plastic deformation,enhancing energy dissipation and reducing the tendency for brittle fracture.This study provides a novel approach to improving the mechanical properties of A356 alloy through grain refinement using CRE Al-Ti-V-B master alloy.展开更多
The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods w...The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.展开更多
The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are asso...The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are associated with the specific microstructure known as the Mille-Feuille(MF)structure that can occur in this alloy as well after proper heat treatment.This study systematically compares the traditional ingot metallurgy method with the Bridgman method(slow cooling),coupled with diverse heat treatments and extrusion process.Microscopic analyses reveal variations in the presence of LPSO phases,MF structure,and especially grain size,leading to divergent mechanical and corrosion properties.The Bridgman approach surprisingly stands out,ensuring superior mechanical properties due to kink and texture strengthening.展开更多
Abiraterone acetate(ABTA)was approved by the USFDA in 2011 for treating metastatic castrationresistant prostate cancer(mCRPC).ABTA exhibits poor aqueous solubility,inadequate dissolution,low oral bioavailability(<1...Abiraterone acetate(ABTA)was approved by the USFDA in 2011 for treating metastatic castrationresistant prostate cancer(mCRPC).ABTA exhibits poor aqueous solubility,inadequate dissolution,low oral bioavailability(<10%),and significant positive food effects.To overcome these limitations,in the present work,ABTA solid dispersions(SDs)were developed by using hot melt extrusion technology(HME)with various grades of hydroxypropyl methylcellulose HME(HPMC HME 15LV and 100LV)at different extrusion temperatures.HPMC HME demonstrated the ability to prevent drug precipitation for up to 120 min compared to the free drug(10 min),sustaining the supersaturation state of the drug in the solution phase and demonstrating the spring and parachute effect.The physical interactions of the ABTA SD’s were evaluated by Fourier transform infrared spectroscopy,powder X-ray diffraction,and differential scanning calorimetry confirming the conversion of ABTA into the amorphous state and the molecular interaction between HPMC and ABTA.The bio-relevant dissolution study of ABTA SD showed 2–5 times higher dissolution in fasted(FaSSIF)and fed(FeSSIF)conditions compared to free ABTA.Pharmacokinetic studies in Wistar rats revealed a 6.22 and 4.94-fold increase in Cmax and AUC0–t for the optimized ABTA SD formulation compared to free ABTA.Accelerated stability testing(40±2℃/75±5%RH,90 days)confirmed retained amorphous state,unchanged drug content and dissolution performance for the optimized formulations.The dissolution and bioavailability studies reflected that the prepared SD of ABTA may improve the therapeutic efficacy of ABTA in prostate cancer.The manufacturing technology is scalable and easy to commercialize,revealing the hope of a better treatment strategy for prostate cancer.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB3710805).
文摘Ultra-high-strength aluminumalloy profile is an ideal choice for aerospace structuralmaterials due to its excellent specific strength and corrosion resistance.However,issues such as uneven metal flow,stress concentration,and forming defects are prone to occur during their extrusion.This study focuses on an Al-Zn-Mg-Cu ultra-high-strength aluminum alloy profile with a double-U,multi-cavity thin-walled structure.Firstly,hot compression experiments were conducted at temperatures of 350○C,400○C,and 450○C,with strain rates of 0.01 and 1.0 s^(−1),to investigate the plastic deformation behavior of the material.Subsequently,a 3D coupled thermo-mechanical extrusion simulation model was established using Deform-3D to systematically analyze the influence of die structure and process parameters on metal flow velocity,effective stress/strain,and temperature distribution.The simulation revealed significant velocity differences,stress concentration,and uneven temperature distribution.Key parameters,including mesh density,extrusion ratio,die fillet,and bearing length,were optimized through full-factorial experiments.This optimization,combined with a stepped flow-guiding die design,effectively improved the metal flow pattern during extrusion.Trial production based on both the initial and optimized parameters were carried out.A comparative analysis demonstrates that the optimized scheme results in a final profile whose cross-section matches the target design closely,with complete filling of complex features and no obvious forming defects.This research provides a valuable reference for the extrusion process optimization and die design of complex-section profiles made from ultra-high-strength aluminum alloys.
基金supported by Sichuan LTWT Metal Materials Co.,Ltd.,Sichuan Province,China(No.21H1367)。
文摘The microstructure and mechanical properties of ZK60 extruded alloy by rapid solidification(RS)and as-cast ingot processes were investigated using optical microscope,scanning electron microscope,X-ray diffraction,electron back-scatter diffraction,and mechanical tests.The results show that the RS ZK60 extruded alloy exhibits relatively high tensile yield strength(TYS),compressive yield strength(CYS)and elongation of 300.8 MPa,303.6 MPa and 18.6%,respectively.The RS ZK60 extruded alloy with an ultra-fine grain size of 1.28μm not only has a weak texture with a maximum polar density of 3.3 but also addresses the tension-compression asymmetry with a CYS/TYS ratio of approximately 1.0.The calculation of the strengthening mechanism indicates that the improvement in the mechanical properties of the RS ZK60 extruded alloy is primarily attributed to grain refinement.
文摘A comparative analysis was performed on poly(lactic acid)(PLA),poly(caprolactone)(PCL),basalt fiber(BF)composites produced using two distinct approaches:direct blending and masterbatching.The limitations of PLA-BF composites with regard to distribution and adhesion are well-documented,as are chemical treatment methods(addition of compatibilisers,surface treatments,silanization).This work aimed to study an industrially relevant potential solution of utilising a PCL-BF masterbatch,prepared as a 50/50 wt.%blend using planetary roller extrusion(PEX)to both improve the distribution and homogeneity of the fibers as well as provide a secondary adhesion site to facilitate improved mechanical properties of the final PLA-PCL-BF composite.The resultant materials were injection moulded to prepare ISO standard test specimens and tested on the basis of their physical properties via tensile testing,impact strength testing,flexural analysis,Fourier transforminfrared spectroscopy and water absorption capability.The results displayed that the incorporation of PCL and BF led to an increase in ductility of the composite materials,allowing for improvements in the inherent brittleness of virgin PLA.Major increases in the impact strength were achieved with the utilisation of a 25% PCL/BF masterbatch,allowing for a greater than 50%increase.As an overall observation,the use of a masterbatching process,opposed to direct blending of the constituent materials allows for a greater consistency of composite to be achieved at the expense of increased gains.
基金Funded by the Fundamental Research Program of Shanxi Province(No.202203021211191)。
文摘To investigate the effects of extrusion temperature on the microstructure and mechanical properties of WE43 magnesium alloy,extrusion experiments were conducted under 330,380,430,and 450℃,and the extrusion ratio was 16.The experimental results indicate that,at a low temperature of 330℃,the alloy precipitates a large amount of second phases rich in Zr elements.Moreover,the texture strength and kernel average misorientation value are the highest,with values of 27.77 and 0.71,respectively.The increase in extrusion temperature leads to a gradual decrease in texture strength and kernel average misorientation value.The strength of the alloy is the highest at an extrusion temperature of 330℃.Its tensile yield stress is 254.7 MPa and ultimate tensile strength is 302.7 MPa,respectively.As the extrusion temperature increases,the strength of the alloy gradually decreases.At an extrusion temperature of 450℃,the tensile yield stress is 181.3 MPa and ultimate tensile strength is 265.7 MPa,respectively.The elongation first increases and then decreases,with an elongation of 20.9%at an extrusion temperature of 330℃.At an extrusion temperature of 430℃,the elongation reaches its maximum value,which is 23.6%.At an extrusion temperature of 450℃,the elongation reaches its lowest value,which is 16.4%.
文摘Most failures in component operation occur due to cyclic loads.Validation has been performed under quasistatic loads,but the fatigue life of components under dynamic loads should be predicted to prevent failures during component service life.Fatigue is a damage accumulation process where loads degrade the material,depending on the characteristics and number of repetitions of the load.Studies on themechanical fatigue of 3D-printedOnyx are limited.In this paper,the strength of 3D-printed Onyx components under dynamic conditions(repetitive loads)is estimated.Fatigue life prediction is influenced bymanufacturing processes,material properties,and applied loads,which can cause scatter in the results due to the interplay of these factors.By utilizing synthetic parameters derived from mechanical properties,the accuracy of fatigue life predictions has been improved significantly,from 23.13%to 98.33%.Additive manufacturing is flexible,but this flexibility generates scatter in the mechanical properties of produced components.This work also proposes the use of synthetic data with a neural network to improve the fatigue life prediction of printedOnyx subjected to tension–tension loads.Experimental uniaxial loads were used to characterize themechanical behaviorofprinted specimens.The experimental datawereused to evaluate thenumerical predictionsobtainedthrough finite element analysis using commercial software and an artificial neural network.The results showed that the use of synthetic data helped improve fatigue life prediction.
文摘Additive Manufacturing,also known as 3D printing,has transformed conventional manufacturing by building objects layer by layer,with material extrusion or fused deposition modeling standing out as particularly popular.However,due to its manufacturing process and thermal nature,internal voids and pores are formed within the thermoplastic materials being fabricated,potentially leading to a decrease in mechanical properties.This paper discussed the effect of printing parameters on the porosity and the mechanical properties of the 3D printed polylactic acid(PLA)through micro-computed tomography(microCT),computational image analysis,and Charpy impact testing.The results for both tests were correlated to investigate the relationship between porosity and Charpy impact strength.PLA samples of 1 cm^(3)×1 cm^(3)×1 cm^(3) were 3D printed at printing temperatures of 180℃,200℃,220℃,and 240℃,and at printing speeds of 50,80,and 110 mm/s,while porosity was measured frommicroCT-reconstructed data.Additionally,impact strength was assessed using a notched Charpy impact tester following ASTMD6610-18.In general,results show that higher printing temperatures and lower printing speeds reduced pore size by improving material flow and fusion,while also increasing impact strength due to better thermal bonding and interlayer adhesion.A maximum 36.8% reduction in mean pore size and a 114% improvement in impact strength were observed at 110 mm/s and 220℃.Conversely,increasing printing speed led to lowerCharpy impact strength.Optimal impact behavior andminimal voids were observed at a printing temperature of 220℃ and a printing speed of 50 mm/s.
基金support of the Korea Institute of Industrial Technol-ogy as“Development of a remote manufacturing system for high-risk,high-difficulty pipe production processes”(kitech EH-25-0004)supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(RS-2023–00237714+2 种基金Development of Dynamic Metrology Tool for CMP Process StabilizationRS-2025–02634755Development of Real-Time Electrical Fire Prevention System Technology Reflecting the Characteristics of Traditional Markets)funded by the Ministry of Trade,Industry&Energy(MOTIE,Republic of Korea).
文摘The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.
基金supported by the National Natural Science Foundation of China(31901608)the National Key Research and Development Plan of China(2021YFC2101402)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2022-IFST)。
文摘High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products.Unfortunately,the extrusion process has been seen as a“black box”with limited information about what occurs inside,causing serious obstacles in developing meat substitutes.This study designed a high-moisture extrusion process and developed 10 new plant-based meat substitutes comparable to the fibrous structure of real animal meat.The study used the Feature-Augmented Principal Component Analysis(FA-PCA)method to visualize and understand the whole extrusion process in three ways systematically and accurately.It established six sets of mathematical models of the high-moisture extrusion process based on 8000 pieces of data,including five types of parameters.The FA-PCA method improved the R^(2) values significantly compared with the PCA method.The Way 3 was the best to predict product quality(Z),demonstrating that the gradually molecular conformational changes(Y^(n'))were critical in controlling the final quality of the plant-based meat substitutes.Moreover,the first visualization platform software for the high-moisture extrusion process has been established to clearly show the“black box”by combining the virtual simulation technology.Through the software,some practice work such as equipment installation,parameter adjustment,equipment disassembly,and data prediction can be easily achieved.
基金supported by the National Key R&D Program of China(Grant No.2017YFB1102800)the National Natural Science Foundation of China for Excellent Young Scholars(Grant No.11722219)+1 种基金the National Natural Science Foundation of China(Grant No.51905439)the Emerging(Interdisciplinary)Cultivation Project of Northwestern Polytechnical University,China(Grant Nos.19SH030403,20SH030201,and 21SH030601).
文摘To fully utilize the in-situ resources on the moon to facilitate the establishment of a lunar habitat is significant to realize the long-term residence of mankind on the moon and the deep space exploration in the future.Thus,intensive research works have been conducted to develop types of 3D printing approach to adapt to the extreme environment and utilize the lunar regolith for in-situ construction.However,the in-situ 3D printing using raw lunar regolith consumes extremely high energy and time.In this work,we proposed a cost-effective melting extrusion system for lunar regolith-based composite printing,and engineering thermoplastic powders are employed as a bonding agent for lunar regolith composite.The high-performance nylon and lunar regolith are uniformly pre-mixed in powder form with different weight fractions.The high-pressure extrusion system is helpful to enhance the interface affinity of polymer binders with lunar regolith as well as maximize the loading ratio of in-situ resources of lunar regolith.Mechanical properties such as tensile strength,elastic modulus,and Poisson’s ratio of the printed specimens were evaluated systematically.Especially,the impact performance was emphasized to improve the resistance of the meteorite impact on the moon.The maximum tensile strength and impact toughness reach 36.2 MPa and 5.15 kJ/m2,respectively.Highpressure melt extrusion for lunar regolith composite can increase the effective loading fraction up to 80 wt.% and relatively easily adapt to extreme conditions for in-situ manufacturing.
文摘The samples obtained by Finite Element Method (FEM) simulation for section extrusion process have been trained on BP Neural Networks. The mapping relationsbetween die's geometrical parameters and energetic parameters, such as stress and strain generated in the die are established. The extrusion process model and its expert system are also determined. The excellent expansibility this system possesses provides a new prospect for the future development of expert system for section extrusion dies.
文摘BACKGROUND Intra-gastric migration of the distal ventriculoperitoneal shunt(VPS)catheter clinically presenting with or without trans-oral extrusion is one of the rare complications of VPS catheter insertion.AIM To identify the demographics,clinical presentation,clinical findings,and results of surgical therapy offered for the treatment of intra-gastric migration of the distal VPS catheter,clinically presented with or without trans-oral extrusion.METHODS An online search was performed for the extraction/retrieval of the published/available literature pertaining to the above-mentioned VPS complication.Manuscripts were searched from PubMed,PMC(PubMed Central),ResearchGate,and Google Scholar databases using various terminology relating to the VPS complications.The first case of migration of a VPS catheter into the stomach was reported in the year 1980,and the data were retrieved from 1980 to December 2022.Cases were categorized into two groups;Group A:Cases who had migration of the distal VPS catheter into the stomach and clinically presented with trans-oral extrusion of the same,and Group B:Cases who had migration of the distal VPS catheter into the stomach,but presented without trans-oral extrusion.RESULTS A total of n=46 cases(n=27;58.69%male,and n=19;41.3%females)were recruited for the systematic review.Group A included n=32,and Group B n=14 cases.Congenital hydrocephalus was the indication for the primary VPS insertion for approximately half of the(n=22)cases.Approximately sixty percent(n=27)of them were children≤5 years of age at the time of the diagnosis of the complication mentioned above.In seventy-two percent(n=33)cases,this complication was detected within 24 mo after the VPS insertion/last shunt revision.Clinical diagnosis was evident for the entire group A cases.Various diagnostic modalities were used to confirm the diagnosis for Group B cases.Various surgical procedures were offered for the management of the complication in n=43 cases of both Groups.In two instances,intra-gastric migration of the distal VPS catheter was detected during the autopsy.This review documented four deaths.CONCLUSION Intra-gastric migration of the peritoneal end of a VPS catheter is one of the rare complications of VPS catheter implantation done for the treatment of hydrocephalus across all age groups.It was more frequently reported in children,although also reported in adults and older people.A very high degree of clinical suspicion is required for the diagnosis of a case of an intra-gastric migration of the distal VPS catheter clinically presenting without transoral extrusion.
基金supported by the National Science and Technology Major Project,China(No.2019-VI-0004-0118)the National Natural Science Foundation of China(No.51771152)the National Key R&D Program of China(No.2018YFB1106800)。
文摘Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.
基金National Basic Research Program of China(Grant No.2015CB932100)
文摘Solvent evaporation method for preparation of nanomatrix has the disadvantages,such as residual organic solvent,environmental pollution,explosion-proofing and so on.To overcome these shortcomings,a series of fenofibrate nanomatrix drug delivery system(NDDS)consisting of nano-porous silica Sylysia■350(S350)and pH sensitive material Eudragit■L100-55(EL100-55)were prepared using hot-melt extrusion(HME),and their in vitro dissolution and in vivo bioavailability were compared.Finally,the formulation with the highest in vivo bioavailability was selected as the optimized formulation for DSC and PXRD characterization.The results showed that the optimized NDDS showed a higher bioavailability than the reference formulation,although there was crystalline form drug remaining in NDDS.The relative bioavailability of the optimized formulation was 157.1%compared with the commercial product Lipanthyl■.In addition,the relative bioavailability of the optimized formulation was 124.8%in comparison with the formulation prepared by solvent evaporation method,showing that the NDDS prepared by the HME method was effective in improving the bioavailability of fenofibrate.In conclusion,HME was a promising method to prepare NDDS.
文摘Extrusion is a common process technique used to fabricate porous materials such as catalysts and membranes. The performance and efficiency of such materials are governed by porosity and pore distribution. The spatial variation of porosity within the catalyst structure can be linked to process variables in the extrusion processes such as extrusion velocity. A change in extrusion velocity can lead to a change in extrusion pressure. The extrusion pressure effect is a combination of die entry deformation and frictional die land shear. In this work, the effect of extrusion velocity on the spatial variation of porosity in a titania-binder extrudate has been studied. Capillary rheometer analysis was done to investigate the effect of extrusion velocity. A segmentation approach was developed to study the spatial variation of porosity at the die wall (sheared region) compared to the unsheared (center) region of the extrudate. The results show that the extrusion pressure effect increases as the velocity increases. The extrusion conditions affect the spatial variation of porosity.
基金supported by the Key Project of Chinese Academy of Engineering(No.2019-XZ-11)the General Project of Chinese Academy of Engineering(No.2023-XY-18)+1 种基金the Open Fund of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials of China(No.HKDNM201907)the Independent Project of State Key Laboratory of Powder Metallurgy,China。
文摘To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.
基金the financial support from Basic Research Projects of Higher Education Institutions of Liaoning Province(Key Research Projects)(No.JYTZD2023108)General Project of Liaoning Provincial Department of Education(Nos.LJKMZ20220462 and JYTMS20231199).
文摘Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of low-temperature extrusion shear specimens(200℃)demonstrates the exceptional strength-ductility synergy,yield strength of 277 MPa,yield strength ratio of 0.95,and elongation of 24%.Microstructural observations reveal the mechanisms underlying its high strength-plasticity synergy at room temperature.This study investigates the effects of different temperature gradients on the microstructure by analyzing experiments conducted at three temperatures:300℃,250℃,and 200◦C.Ultimately,the formation mechanism of the bimodal microstructure obtained at 200℃ is elucidated.The distinctive crystallographic texture oriented at 34°relative to the loading axis direction effectively mitigates stress concentration by inducing the synergistic activation of multiple slip systems.Furthermore,the transition trends of different slip systems and texture evolution during tensile deformation are validated through Visco-Plastic Self-Consistent(VPSC)simulations and corroborated by microstructural analysis.With geometrically necessary dislocation(GND)density(4.28×10^(15)m^(-2))and pyramidal slip activation(~45%).This study has successfully broken through the bottleneck of strength-ductility trade-off in magnesium alloys,providing theoretical support for the development of high-reliability magnesium alloys.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFB3706801)the National Natural Science Foundation of China (Grant Nos.U2341253,52371019,U2241232)+2 种基金the Dalian High-level Talents Innovation Support Program (Grant No.2021RD06)the Applied Basic Research Program of Liaoning Province (Grant No.2022JH2/101300003)the Natural Science Foundation of Liaoning Province (Grant Nos.2022-BS-262,JYTMS20230031)。
文摘Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys were analyzed by XRD,SEM,and TEM.The effects of master alloy addition and holding time on the microstructure and mechanical properties of A356 alloy were investigated.Under the optimum refiner addition of 0.3wt.%and the holding time of 20 min,the average grain size of the refined A356 alloy is 151.8±9.11μm,89.62%lower than that of original A356 alloy.The tensile strength and elongation of as-cast A356refined alloy are 196.11 MPa and 5.75%,respectively.After T6 treatment,the tensile strength and elongation of A356 refined alloy are 290.1 MPa and 3.09%,respectively.The fracture morphology is characterized by a predominance of along-crystal fracture with a small amount of through-crystal fracture,attributed to the refined grains.Finer grains promote crack path deflection and localized plastic deformation,enhancing energy dissipation and reducing the tendency for brittle fracture.This study provides a novel approach to improving the mechanical properties of A356 alloy through grain refinement using CRE Al-Ti-V-B master alloy.
基金supported by the general project of the National Natural Science Foundation of China(No.52071042)Chongqing Natural Science Foundation Project,China(Nos.CSTB2023NSCQ-MSX0079,cstc2021ycjh-bgzxm0148)Graduate Student Innovation Program of Chongqing University of Technology,China(No.gzlcx20232008).
文摘The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.
基金supported by Japan Society for the Promotion of Science(KAKENHI Grant-in-Aid for Scientific Research,18H05475,18H05476 and JP20H00312)MRC International Collaborative Research Grant+4 种基金The authors would like to thank the Czech Science Foundation(Project No.22-22248S)specific university research(A1_FCHT_2024_007)for financial supportsupported by the Ministry of Education,Youth,and Sports of the Czech Republic.Project No.CZ.02.01.01/00/22_008/0004591co-funded by the European UnionCzechNanoLab project LM2023051 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements/sample fabrication at LNSM Research Infrastructure。
文摘The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are associated with the specific microstructure known as the Mille-Feuille(MF)structure that can occur in this alloy as well after proper heat treatment.This study systematically compares the traditional ingot metallurgy method with the Bridgman method(slow cooling),coupled with diverse heat treatments and extrusion process.Microscopic analyses reveal variations in the presence of LPSO phases,MF structure,and especially grain size,leading to divergent mechanical and corrosion properties.The Bridgman approach surprisingly stands out,ensuring superior mechanical properties due to kink and texture strengthening.
文摘Abiraterone acetate(ABTA)was approved by the USFDA in 2011 for treating metastatic castrationresistant prostate cancer(mCRPC).ABTA exhibits poor aqueous solubility,inadequate dissolution,low oral bioavailability(<10%),and significant positive food effects.To overcome these limitations,in the present work,ABTA solid dispersions(SDs)were developed by using hot melt extrusion technology(HME)with various grades of hydroxypropyl methylcellulose HME(HPMC HME 15LV and 100LV)at different extrusion temperatures.HPMC HME demonstrated the ability to prevent drug precipitation for up to 120 min compared to the free drug(10 min),sustaining the supersaturation state of the drug in the solution phase and demonstrating the spring and parachute effect.The physical interactions of the ABTA SD’s were evaluated by Fourier transform infrared spectroscopy,powder X-ray diffraction,and differential scanning calorimetry confirming the conversion of ABTA into the amorphous state and the molecular interaction between HPMC and ABTA.The bio-relevant dissolution study of ABTA SD showed 2–5 times higher dissolution in fasted(FaSSIF)and fed(FeSSIF)conditions compared to free ABTA.Pharmacokinetic studies in Wistar rats revealed a 6.22 and 4.94-fold increase in Cmax and AUC0–t for the optimized ABTA SD formulation compared to free ABTA.Accelerated stability testing(40±2℃/75±5%RH,90 days)confirmed retained amorphous state,unchanged drug content and dissolution performance for the optimized formulations.The dissolution and bioavailability studies reflected that the prepared SD of ABTA may improve the therapeutic efficacy of ABTA in prostate cancer.The manufacturing technology is scalable and easy to commercialize,revealing the hope of a better treatment strategy for prostate cancer.
