In view of the composition analysis and identification of ancient glass products, L1 regularization, K-Means cluster analysis, elbow rule and other methods were comprehensively used to build logical regression, cluste...In view of the composition analysis and identification of ancient glass products, L1 regularization, K-Means cluster analysis, elbow rule and other methods were comprehensively used to build logical regression, cluster analysis, hyper-parameter test and other models, and SPSS, Python and other tools were used to obtain the classification rules of glass products under different fluxes, sub classification under different chemical compositions, hyper-parameter K value test and rationality analysis. Research can provide theoretical support for the protection and restoration of ancient glass relics.展开更多
The influence of Ga doping on the structure and mechanical properties of B2-CuZr phase reinforced larger-size CuZrAlY metallic glass composites was investigated by experiments and simulations.The result showed that as...The influence of Ga doping on the structure and mechanical properties of B2-CuZr phase reinforced larger-size CuZrAlY metallic glass composites was investigated by experiments and simulations.The result showed that as Ga content increased,the glass-forming ability of CuZrAlY metallic glass composites was gradually enhanced.Section morphology and thermal analysis indicated that Ga doping induced the decreased content of the crystals and the enlargement of the super-cooled liquid region,and increased activation energy for crystallization.Ga also stabilized the B2-CuZr phase.Characterization of the microstructure and mechanical test results suggested that the B19'-CuZr phase disappeared in the as-cast samples after adding Ga,and the martensitic transformation of the B2-CuZr phase was hindered when Ga content increased.The evolution mechanism of mechanical behaviors of the CuZr-based metallic glass composites during Ga doping was clarified by first-principles calculation.The results would be beneficial to the development and application of large-size CuZr-based metallic glass composites.展开更多
Mullite-silica rich glass(MSRG)composites are a more efficient material than chamotte for industrial utilization of clay in refractory applications.The properties of the MSRG composites depend on the amount and compos...Mullite-silica rich glass(MSRG)composites are a more efficient material than chamotte for industrial utilization of clay in refractory applications.The properties of the MSRG composites depend on the amount and composition of the mulite and glass phases,which are related to the chemical composition of the MSRG composites based on clay.In the present work,the relationship between the phase and the chemical composition of the MSRG composites,and the effects of the chemical composition of the glass phase on the viscosity and coefficient of thermal expansion(CTE)of the glass phase were discussed on the basis of the measurements on 17 MSRG composite samples produced from clay.It is found that the Al_(2)O_(3)/SiO_(2) ratio(AS ratio)in clay strongly affects the amount of the mullite and glass phases in the MSRG composites,and the distributions of SiO_(2),TiO_(2)and Al_(2)O_(3) contents in the mullite and glass phases.With the increase of the A/S ratio of clay,the mullite content increases but the the glass phase content decreases in the MSRG composites.The viscosity and CTE of the glass phase depend on its A/S ratio and the amount of impurity oxides.When the A/S ratio in the glass phase is less than 0.15,the viscosity of the liquid formed by the melting of the glass phase at elevated temperatures rapidly increases with the decrease in the A/S ratio.The CTE of the glass phase depends on the contents of Si0_(2)and(K_(2)O+Na_(2)O).展开更多
A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of sho...A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of short glass fiber-based SMPCs,this work explores the potential for programming below the glass transition temperature(Tg)for epoxy-based SMPCs.To mitigate the inherent brittleness of the SMPC during deformation,a linear polymer is incorporated,and a temperature between room temperature and Tg is chosen as the deformation temperature to study the shape memory properties.The findings demonstrate an enhancement in shape fixity and recovery stress,alongside a reduction in shape recovery,with the incorporation of short glass fibers.In addition to tensile properties,thermal properties such as thermal conductivity,specific heat capacity,and glass transition temperature are investigated for their dependence on fiber content.Microscopic properties,such as fiber-matrix adhesion and the dispersion of glass fibers,are examined through Scanning Electron Microscope imaging.The fiber length distribution and mean fiber lengths are also measured for different fiber fractions.展开更多
This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Com...This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Composite laminates are fabricated with varying glass fiber(40-60 wt.%)and nanoclay(0-4 wt.%)contents.Water absorption is evaluated for 70 days of immersion following ASTM D570-98 standards.The inclusion of nanoclay reduces water uptake by creating a tortuous path for moisture diffusion due to its high aspect ratio and platelet morphology,thereby enhancing the composite’s barrier properties.The ANN model is developed with a 3-4-1 feedforward structure and learned through the Levenberg-Marquardt algorithm with soaking time(7 to 70 days),fiber content(40,50,and 60 wt.%)and nanoclay content(0,2,and 4 wt.%)as input parameters.The model’s output is the water uptake percentage.The model has high prediction efficiency,with a correlation coefficient(R)of 0.998 and a mean squared error of 1.38×10^(-4).Experimental and predicted values are in excellent agreement,ensuring the reliability of the ANN for the simulation of nonlinear water absorption behavior.The results identify the synergistic capability of nanoclay and fiber concentration to reduce water absorption and prove the feasibility of ANN as a substitute for time-consuming testing in composite durability estimation.展开更多
Metallic glass matrix composites(BMGCs)with compositions of[(Zr_(0.5)Cu_(0.5))_(0.925)Al_(0.07)Sn_(0.005)]_(100-x)Ta_(x)(atomic fraction,%,x=3,5,7)were successfully prepared via dealloying in metallic melt.The reinfor...Metallic glass matrix composites(BMGCs)with compositions of[(Zr_(0.5)Cu_(0.5))_(0.925)Al_(0.07)Sn_(0.005)]_(100-x)Ta_(x)(atomic fraction,%,x=3,5,7)were successfully prepared via dealloying in metallic melt.The reinforcing phase in these alloys has core-shell hybrid structure with Ta-rich particles as core and B2-CuZr as shell.In this method,the dealloyed Ta from Zr-Ta pre-alloys maintained in solid state and aggregated to form the fine Ta-rich phase in the final products.This effectively decreases the size of Ta-rich phase compared with that prepared via conventional arc-melting,where the Ta-rich phase was formed through dissolving and precipitation.Among the three compositions,[(Zr_(0.5)Cu_(0.5))_(0.925)Al_(0.07)Sn_(0.005)]_(95)Ta_(5) showed the highest plastic strain of 11.2%,much higher than that of the arc-melted counterparts(4.3%).Such improvement in mechanical properties was related with the refined core-shell hybrid reinforcing structure,which could hinder the rapid propagation of main shear band more efficiently and cause them to branch and proliferate at the interface.展开更多
Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite an...Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite and 3D printing have promising applications in aerospace,automobile,rail transit,etc.In this paper,a high-temperature melt impregnation method was used to successfully prepare the 3D printing prepreg filaments of the aforementioned composite.In the FDM 3D printing equipment,a nozzle of high thermal conductivity and wear-resistant copper alloy and a PEEK-based carbon fiber thermoplastic composite build plate with uniform temperature control were innovatively introduced to effectively improve the quality of 3D printing.The porosity of the 3D printed samples produced from the composite prepreg filament was analyzed under different printing parameters,and the mechanical properties and fracture mechanism of the printed parts were studied.The results show that the printing layer thickness,printing speed,printing temperature and build plate temperature have varying effects on the porosity of printed parts,which in turn affects tensile strength and the interlaminar shear strength(ILSS).When the printing layer thickness is 0.4 mm,printing speed is 2 mm/s,nozzle temperature is 430℃ and build plate temperature is 150℃,the tensile strength and ILSS of the composite printed parts reach their maximum values of 463.76 and 24.95 MPa,respectively.Microscopic analysis of the fracture morphology of the tensile specimens reveals that the 3D printed CGF/PEEK composite sample has three types of fracture mode,which are single filament bundle fracture,fracture mode of delamination,and fracture failure of the sample at the cross-section.The essence of the above three kinds of fracture mode is the difference of the interface bonding force of 3D printed CGF/PEEK composites.The fracture failure at the cross-section is that the continuous glass fibers in the composite are pulled out until they break,which is the main form of the failure of the composite under tensile load.The interfacial region of the composite is prone to microscopic defects such as voids and delamination during 3D printing,which become the most vulnerable link of the composite.Understanding the relationship between voids and fracture behavior lays a foundation for defect suppression and performance improvement of subsequent printed parts.展开更多
Li_(2)O-Al_(2)O_(3)-SiO_(2) based glasses were investigated as potential protection glass for electronic devices due to their excellent mechanical properties,such as high hardness,toughness,and scratch resistance.In t...Li_(2)O-Al_(2)O_(3)-SiO_(2) based glasses were investigated as potential protection glass for electronic devices due to their excellent mechanical properties,such as high hardness,toughness,and scratch resistance.In this paper,Li_(2)O-Na_(2)O-Al_(2)O_(3)-SiO_(2) glass with different Li_(2)O/Na_(2)O ratio components were prepared by meltquenching method,and the effects of Na_(2)O/Li_(2)O ratio on the glass densities,structure,thermal,mechanical properties,and chemical stabilities were studied.The experimental results indicate that the glass transition temperature increases with the increases in Na_(2)O/Li_(2)O ratios,due to larger ion radius.While the thermal expansion coefficient slightly decreases from 11.4×10^(-6) to 11.09×10^(-6)/℃.The elastic modulus increases from 57 to 72 GPa.The bending strength reaches maximum 80.90 MPa when the Na_(2)O/Li_(2)O ratio is 1.7,then decreases as the ratio further increases.In addition,the Vicker’s hardness gets to 7.37 GPa with largest Na_(2)O/Li_(2)O ratio.Moreover,the dielectric loss and dielectric constant increases as the ratio increases.The Raman structure analysis shows the Q4[Si-O-Si]decreases as Na_(2)O/Li_(2)O ratio increases,which is responsible for the characteristic properties change.Moreover,the glass shows lowest mass loss in 10vol%HF solutions when the ratio is 1.4,while 1.7 in 5wt%NaOH solution.展开更多
BaO is the most common consideration in the preparation of newcrystal glass for getting rid of lead content in the glass andceramic wares to protect hu- man health and environment. But forkeeping the glass products...BaO is the most common consideration in the preparation of newcrystal glass for getting rid of lead content in the glass andceramic wares to protect hu- man health and environment. But forkeeping the glass products' properties to meet the requirements ofthe tradi- tional crystal glass, B_2O_3, Al_2O_3, TiO_2, SrO and ZnOetc (at a special ratio) had been researched with BaO to con- stitutea mixture to replace the lead content in the glass compositions.展开更多
In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has mu...In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present （Cu0.6Zr0.3Ti0.1）95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.展开更多
With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawat...With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawater lubrication are still very fewer, especially experimental research. The influences of smooth and non-smooth surface on the frictional properties of the glass fiber-epoxy resin composite（GF/EPR） coupled with stainless steel 316 L are investigated under natural seawater lubrication in this paper. The tested non-smooth surfaces include the surfaces with semi-spherical pits, the conical pits, the cone-cylinder combined pits, the cylindrical pits and through holes. The friction and wear tests are performed using a ring-on-disc test rig under 60 N load and 1000 r/min rotational speed. The tests results show that GF/EPR with bionic non-smooth surface has quite lower friction coefficient and better wear resistance than GF/EPR with smooth surface without pits. The average friction coefficient of GF/EPR with semi-spherical pits is 0.088, which shows the largest reduction is approximately 63.18% of GF/EPR with smooth surface. In addition, the wear debris on the worn surfaces of GF/EPR are observed by a confocal scanning laser microscope. It is shown that the primary wear mechanism is the abrasive wear. The research results provide some design parameters for non-smooth surface, and the experiment results can serve as a beneficial supplement to non-smooth surface study.展开更多
Bionic non-smooth surface is widely applied in metal and ceramics materials. In order to introduce this technology to high pressure seawater pump, the influence of bionic non-smooth surface on the engineering plastics...Bionic non-smooth surface is widely applied in metal and ceramics materials. In order to introduce this technology to high pressure seawater pump, the influence of bionic non-smooth surface on the engineering plastics used in pump should be investigated. The comparative tests are carried out with a ring-on-disc configuration under 800, 1000, 1200 and 1400 r/min in order to research the influence of the bionic non-smooth surface on glass fiber-epoxy resin composite（GF/EPR） under natural seawater lubrication. The disc surfaces are textured with five kinds of pits, which are semi-spherical, conical, cone-cylinder combined, cylindrical pits and through holes, respectively. A smooth surface is tested as reference. The results show that the lubrication performance of dimpled GF/EPR sample is much better than that of the smooth sample under all rotational speeds. The semi-spherical pits surface has more obvious friction reduction than the others, which shows that the least reduction is approximately 43.29% of smooth surface under 1200 r/rain. However, the wear level is only marginally influenced by dimples. The surface morphology investigations disclose severe modifications caused by abrasive wear primarily. The results are helpful to vary friction properties of GF/EPR by non-smooth surface, or provide references to the design of non-smooth surfaces under certain condition.展开更多
Introducing ductile crystalline dendrites into a glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to improve the poor ductility of bulk metallic glasses(BMGs).However,the presence of s...Introducing ductile crystalline dendrites into a glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to improve the poor ductility of bulk metallic glasses(BMGs).However,the presence of soft crystalline phases tends to decrease the strength and causes the strength-ductility tradeoff.Here,relying on the flexible laser additive manufacturing(LAM)technique that allows the composition tailoring of each layer,we successfully fabricate a lamellated Zr-based BMGC constructed by the alternating superimposition of soft and hard layers.The lamellated BMGC shows an exceptional combination of yield strength(∼1.2 GPa)and ductility(∼5%).Such enhanced strength-ductility synergy is attributed to the asynchronous deformation at two scales,i.e.,inter-laminar and intra-laminar,and the unique dual-scale Ta particles that uniformly distribute on the amorphous matrix.The lamellated structure design motif,enabled by the flexible LAM technology,provides a new window for the development of high-performance BMGCs.It is also applicable to the synergistic enhancement of strength and plasticity of other brittle metallic materials.展开更多
The synthesis of martensitic or shape-memory bulk metallic glass composites(BMGCs)via solidification of the glass-forming melts requires the meticulous selection of the chemical composition and the proper choice of th...The synthesis of martensitic or shape-memory bulk metallic glass composites(BMGCs)via solidification of the glass-forming melts requires the meticulous selection of the chemical composition and the proper choice of the processing parameters in order to ensure that the glassy matrix coexists with the desired amount of austenitic phase.Unfortunately,a relatively limited number of such systems,where austenite and glassy matrix coexist over a wide range of compositions,is available.Here,we study the effective-ness of powder metallurgy as an alternative to solidification for the synthesis of shape memory BMGCs.Zr_(48)Cu_(36)Al_(8)Ag_(8)matrix composites with different volume fractions of Ni_(50.6)Ti_(49.4)are fabricated using hot pressing and their microstructure,mechanical properties and deformation mechanism are investigated employing experiments and simulations.The results demonstrate that shape-memory BMGCs with tun-able microstructures and properties can be synthesized by hot pressing.The phase stability of the glass and austenitic components across a wide range of compositions allows us to examine fundamental as-pects in the field of shape memory BMGCs,including the effect of the confining stress on the martensitic transformation exerted by the glassy matrix,the contribution of each phase to the plasticity and the mechanism responsible for shear band formation.The present method gives a virtually infinite choice among the possible combinations of glassy matrices and shape memory phases,expanding the range of accessible shape memory BMGCs to systems where the glassy and austenitic phases do not form simul-taneously using the solidification route.展开更多
The unusual glass-forming ability（GFA） of the Zr48Cu36Ag8Al8 alloy and the high ductility of the Zr48Cu36Ag8Al8 metallic glass-matrix composites containing Ta powder were reported.The bulk metallic glass rod with a ...The unusual glass-forming ability（GFA） of the Zr48Cu36Ag8Al8 alloy and the high ductility of the Zr48Cu36Ag8Al8 metallic glass-matrix composites containing Ta powder were reported.The bulk metallic glass rod with a diameter of 25 mm was successfully synthesized using copper mold casting for the Zr48Cu36Ag8Al8 alloy.High GFA of this alloy was found to be related to a large supercooled liquid region and a quaternary eutectic point with low melting temperature.The bulk metallic glass matrix composites were prepared by introducing extra Ta particles into the Zr48Cu36Ag8Al8 melt.The composites consist of Ta particles homogenously distributed in the Zr48Cu36Ag8Al8 metallic glass matrix.The optimum content of Ta powder is 10at%for the composite with the highest plasticity,which shows a plastic strain of 31%.展开更多
Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization proce...Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.展开更多
Using melt infiltration casting at different temperatures （965, 990 and 1015 °C） for different time （10 and 15 min）, the composites of （Cu50Zr43Al7）99.5Si0.5 bulk metallic glass reinforced with tungsten wir...Using melt infiltration casting at different temperatures （965, 990 and 1015 °C） for different time （10 and 15 min）, the composites of （Cu50Zr43Al7）99.5Si0.5 bulk metallic glass reinforced with tungsten wires were produced. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and quasi-static compression tests were carried out to evaluate the microstructure and mechanical properties. The results show that the maximum ultimate compressive strength and strain-to-failure of about 1880 MPa and 16.7% were achieved, respectively, at the infiltration temperature of 965 °C for 15 min.展开更多
Monolithic bulk metallic glass and glass matrix composites with a relative density above 98%were produced by processing Cu_(46)Zr_(46)Al_(8)(at.%)via selective laser melting(SLM).Their microstructures and mechanical p...Monolithic bulk metallic glass and glass matrix composites with a relative density above 98%were produced by processing Cu_(46)Zr_(46)Al_(8)(at.%)via selective laser melting(SLM).Their microstructures and mechanical properties were systematically examined.B2 CuZr nanocrystals(30-100 nm in diameter)are uniformly dispersed in the glassy matrix when SLM is conducted at an intermediate energy input.These B2 CuZr nanocrystals nucleate the oxygen-stabilized big cube phase during a remelting step.The presence of these nanocrystals increases the structural heterogeneity as indirectly revealed by mircrohardness and nanoindentation measurements.The corresponding maps in combination with calorimetric data indicate that the glassy phase is altered by the processing conditions.Despite the formation of crystals and a high overall free volume content,all additively manufactured samples fail at lower stress than the as-cast glass and without any plastic strain.The inherent brittleness is attributed to the presence of relatively large pores and the increased oxygen content after selective laser melting.展开更多
In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs wa...In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_（47.5）Zr_（33）Cu_（5.8）Co_3Be_（12.5）（at.%） BMGC was studied by the secondary ion mass spectrometry（SIMS） and the electron energy loss spectroscopy（EELS）.It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.展开更多
In this study,non-toxic in-situβphases of reinforced Ti/Zr-based bulk metallic glass matrix composites(BMGCs)of(Ti_(0.65)Zr_(0.35))100-xCux(x=5,10,15 at.%)are fabricated via selective laser melting.The effect of Cu c...In this study,non-toxic in-situβphases of reinforced Ti/Zr-based bulk metallic glass matrix composites(BMGCs)of(Ti_(0.65)Zr_(0.35))100-xCux(x=5,10,15 at.%)are fabricated via selective laser melting.The effect of Cu content on phase formation,microstructure,and mechanical properties is investigated.The average volume fraction and width of theβphase decreases with increasing Cu content,while a more amorphous phase and the(Ti,Zr)_(2)Cu phase forms.In the center zone of the molten pool,theβphase grows in the direction of the temperature gradient,and the amorphous phase distributes among theβphases.This occurs using:sphere morphology(for x=5),a more continuous elongated sphere and network morphology(for x=10),and network morphology(for x=15),respectively.In the edge zone of the molten pool,due to the smaller cooling rate and the existence of a partially molten zone,theβphase becomes coarser,and an amorphous phase forms for more continuous networks.Furthermore,the hardness improves significantly with increasing Cu content.No crack is found for x=5.Although the average volume fraction of theβphase for x=5 is about 90%,the compression yield strength is 1386±64 MPa,reaching to an average level of conventionally fabricated counterparts,due to finer microstructure,and twinning and martensitic transformation of theβphase.展开更多
文摘In view of the composition analysis and identification of ancient glass products, L1 regularization, K-Means cluster analysis, elbow rule and other methods were comprehensively used to build logical regression, cluster analysis, hyper-parameter test and other models, and SPSS, Python and other tools were used to obtain the classification rules of glass products under different fluxes, sub classification under different chemical compositions, hyper-parameter K value test and rationality analysis. Research can provide theoretical support for the protection and restoration of ancient glass relics.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2020A1515110065).
文摘The influence of Ga doping on the structure and mechanical properties of B2-CuZr phase reinforced larger-size CuZrAlY metallic glass composites was investigated by experiments and simulations.The result showed that as Ga content increased,the glass-forming ability of CuZrAlY metallic glass composites was gradually enhanced.Section morphology and thermal analysis indicated that Ga doping induced the decreased content of the crystals and the enlargement of the super-cooled liquid region,and increased activation energy for crystallization.Ga also stabilized the B2-CuZr phase.Characterization of the microstructure and mechanical test results suggested that the B19'-CuZr phase disappeared in the as-cast samples after adding Ga,and the martensitic transformation of the B2-CuZr phase was hindered when Ga content increased.The evolution mechanism of mechanical behaviors of the CuZr-based metallic glass composites during Ga doping was clarified by first-principles calculation.The results would be beneficial to the development and application of large-size CuZr-based metallic glass composites.
基金Research Project of Hubei Provincial Department of Science and Technology(Grant no.2024CSA075)Key Project of the National Natural Science Foundation of China(Grant No.U21A2058)for fnancially supporting this work.
文摘Mullite-silica rich glass(MSRG)composites are a more efficient material than chamotte for industrial utilization of clay in refractory applications.The properties of the MSRG composites depend on the amount and composition of the mulite and glass phases,which are related to the chemical composition of the MSRG composites based on clay.In the present work,the relationship between the phase and the chemical composition of the MSRG composites,and the effects of the chemical composition of the glass phase on the viscosity and coefficient of thermal expansion(CTE)of the glass phase were discussed on the basis of the measurements on 17 MSRG composite samples produced from clay.It is found that the Al_(2)O_(3)/SiO_(2) ratio(AS ratio)in clay strongly affects the amount of the mullite and glass phases in the MSRG composites,and the distributions of SiO_(2),TiO_(2)and Al_(2)O_(3) contents in the mullite and glass phases.With the increase of the A/S ratio of clay,the mullite content increases but the the glass phase content decreases in the MSRG composites.The viscosity and CTE of the glass phase depend on its A/S ratio and the amount of impurity oxides.When the A/S ratio in the glass phase is less than 0.15,the viscosity of the liquid formed by the melting of the glass phase at elevated temperatures rapidly increases with the decrease in the A/S ratio.The CTE of the glass phase depends on the contents of Si0_(2)and(K_(2)O+Na_(2)O).
文摘A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of short glass fiber-based SMPCs,this work explores the potential for programming below the glass transition temperature(Tg)for epoxy-based SMPCs.To mitigate the inherent brittleness of the SMPC during deformation,a linear polymer is incorporated,and a temperature between room temperature and Tg is chosen as the deformation temperature to study the shape memory properties.The findings demonstrate an enhancement in shape fixity and recovery stress,alongside a reduction in shape recovery,with the incorporation of short glass fibers.In addition to tensile properties,thermal properties such as thermal conductivity,specific heat capacity,and glass transition temperature are investigated for their dependence on fiber content.Microscopic properties,such as fiber-matrix adhesion and the dispersion of glass fibers,are examined through Scanning Electron Microscope imaging.The fiber length distribution and mean fiber lengths are also measured for different fiber fractions.
文摘This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Composite laminates are fabricated with varying glass fiber(40-60 wt.%)and nanoclay(0-4 wt.%)contents.Water absorption is evaluated for 70 days of immersion following ASTM D570-98 standards.The inclusion of nanoclay reduces water uptake by creating a tortuous path for moisture diffusion due to its high aspect ratio and platelet morphology,thereby enhancing the composite’s barrier properties.The ANN model is developed with a 3-4-1 feedforward structure and learned through the Levenberg-Marquardt algorithm with soaking time(7 to 70 days),fiber content(40,50,and 60 wt.%)and nanoclay content(0,2,and 4 wt.%)as input parameters.The model’s output is the water uptake percentage.The model has high prediction efficiency,with a correlation coefficient(R)of 0.998 and a mean squared error of 1.38×10^(-4).Experimental and predicted values are in excellent agreement,ensuring the reliability of the ANN for the simulation of nonlinear water absorption behavior.The results identify the synergistic capability of nanoclay and fiber concentration to reduce water absorption and prove the feasibility of ANN as a substitute for time-consuming testing in composite durability estimation.
基金supported by the National Natural Science Foundation of China(Nos.52101138,52201075)Natural Science Foundation of Hubei Province,China(Nos.2023AFB798,2022CFB614)+3 种基金Shenzhen Science and Technology Program,China(No.JCYJ20220530160813032)State Key Laboratory of Solidification Processing in NWPU,China(Nos.SKLSP202309,SKLSP202308)Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515011227)State Key Laboratory of Powder Metallurgy of Central South University,China(No.Sklpm-KF-05).
文摘Metallic glass matrix composites(BMGCs)with compositions of[(Zr_(0.5)Cu_(0.5))_(0.925)Al_(0.07)Sn_(0.005)]_(100-x)Ta_(x)(atomic fraction,%,x=3,5,7)were successfully prepared via dealloying in metallic melt.The reinforcing phase in these alloys has core-shell hybrid structure with Ta-rich particles as core and B2-CuZr as shell.In this method,the dealloyed Ta from Zr-Ta pre-alloys maintained in solid state and aggregated to form the fine Ta-rich phase in the final products.This effectively decreases the size of Ta-rich phase compared with that prepared via conventional arc-melting,where the Ta-rich phase was formed through dissolving and precipitation.Among the three compositions,[(Zr_(0.5)Cu_(0.5))_(0.925)Al_(0.07)Sn_(0.005)]_(95)Ta_(5) showed the highest plastic strain of 11.2%,much higher than that of the arc-melted counterparts(4.3%).Such improvement in mechanical properties was related with the refined core-shell hybrid reinforcing structure,which could hinder the rapid propagation of main shear band more efficiently and cause them to branch and proliferate at the interface.
基金supported by the National Key Research and Development Program Project of China(Grant No.2018YFB1106700).
文摘Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite and 3D printing have promising applications in aerospace,automobile,rail transit,etc.In this paper,a high-temperature melt impregnation method was used to successfully prepare the 3D printing prepreg filaments of the aforementioned composite.In the FDM 3D printing equipment,a nozzle of high thermal conductivity and wear-resistant copper alloy and a PEEK-based carbon fiber thermoplastic composite build plate with uniform temperature control were innovatively introduced to effectively improve the quality of 3D printing.The porosity of the 3D printed samples produced from the composite prepreg filament was analyzed under different printing parameters,and the mechanical properties and fracture mechanism of the printed parts were studied.The results show that the printing layer thickness,printing speed,printing temperature and build plate temperature have varying effects on the porosity of printed parts,which in turn affects tensile strength and the interlaminar shear strength(ILSS).When the printing layer thickness is 0.4 mm,printing speed is 2 mm/s,nozzle temperature is 430℃ and build plate temperature is 150℃,the tensile strength and ILSS of the composite printed parts reach their maximum values of 463.76 and 24.95 MPa,respectively.Microscopic analysis of the fracture morphology of the tensile specimens reveals that the 3D printed CGF/PEEK composite sample has three types of fracture mode,which are single filament bundle fracture,fracture mode of delamination,and fracture failure of the sample at the cross-section.The essence of the above three kinds of fracture mode is the difference of the interface bonding force of 3D printed CGF/PEEK composites.The fracture failure at the cross-section is that the continuous glass fibers in the composite are pulled out until they break,which is the main form of the failure of the composite under tensile load.The interfacial region of the composite is prone to microscopic defects such as voids and delamination during 3D printing,which become the most vulnerable link of the composite.Understanding the relationship between voids and fracture behavior lays a foundation for defect suppression and performance improvement of subsequent printed parts.
基金by the Key Research Project of Hainan Province(No.ZDYF2021GXJS027)the Shenzhen Free Investigation Fundamental Research Project(2021Szvup107)。
文摘Li_(2)O-Al_(2)O_(3)-SiO_(2) based glasses were investigated as potential protection glass for electronic devices due to their excellent mechanical properties,such as high hardness,toughness,and scratch resistance.In this paper,Li_(2)O-Na_(2)O-Al_(2)O_(3)-SiO_(2) glass with different Li_(2)O/Na_(2)O ratio components were prepared by meltquenching method,and the effects of Na_(2)O/Li_(2)O ratio on the glass densities,structure,thermal,mechanical properties,and chemical stabilities were studied.The experimental results indicate that the glass transition temperature increases with the increases in Na_(2)O/Li_(2)O ratios,due to larger ion radius.While the thermal expansion coefficient slightly decreases from 11.4×10^(-6) to 11.09×10^(-6)/℃.The elastic modulus increases from 57 to 72 GPa.The bending strength reaches maximum 80.90 MPa when the Na_(2)O/Li_(2)O ratio is 1.7,then decreases as the ratio further increases.In addition,the Vicker’s hardness gets to 7.37 GPa with largest Na_(2)O/Li_(2)O ratio.Moreover,the dielectric loss and dielectric constant increases as the ratio increases.The Raman structure analysis shows the Q4[Si-O-Si]decreases as Na_(2)O/Li_(2)O ratio increases,which is responsible for the characteristic properties change.Moreover,the glass shows lowest mass loss in 10vol%HF solutions when the ratio is 1.4,while 1.7 in 5wt%NaOH solution.
基金Supported by the Youth Foundation of Beijing Graduate School of Wuhan University of Technology(No.97-QW)
文摘BaO is the most common consideration in the preparation of newcrystal glass for getting rid of lead content in the glass andceramic wares to protect hu- man health and environment. But forkeeping the glass products' properties to meet the requirements ofthe tradi- tional crystal glass, B_2O_3, Al_2O_3, TiO_2, SrO and ZnOetc (at a special ratio) had been researched with BaO to con- stitutea mixture to replace the lead content in the glass compositions.
基金Project(51371149)supported by the National Natural Science Foundation of ChinaProject(151048)supported by the HUO Ying-dong Young Teacher Fund+4 种基金Project(2015ZF53066)supported by the Aeronautical Science Foundation of ChinaProject(92-QZ-2014)supported by the Free Research Fund of State Key Laboratory of Solidification Processing,ChinaProject(2015KJXX-10)supported by Shaanxi Young Stars of Science and Technology,ChinaProejct(2011CB610403)supported by the National Basic Research Program of ChinaProject(51125002)supported by the National Science Funds for Distinguished Young Scientists,China
文摘In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present （Cu0.6Zr0.3Ti0.1）95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.
基金Supported by National Natural Science Foundation of China(Grant No.51375421)Hebei Provincial Key Project of Science and Technology Research of(ZD20131027)
文摘With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawater lubrication are still very fewer, especially experimental research. The influences of smooth and non-smooth surface on the frictional properties of the glass fiber-epoxy resin composite（GF/EPR） coupled with stainless steel 316 L are investigated under natural seawater lubrication in this paper. The tested non-smooth surfaces include the surfaces with semi-spherical pits, the conical pits, the cone-cylinder combined pits, the cylindrical pits and through holes. The friction and wear tests are performed using a ring-on-disc test rig under 60 N load and 1000 r/min rotational speed. The tests results show that GF/EPR with bionic non-smooth surface has quite lower friction coefficient and better wear resistance than GF/EPR with smooth surface without pits. The average friction coefficient of GF/EPR with semi-spherical pits is 0.088, which shows the largest reduction is approximately 63.18% of GF/EPR with smooth surface. In addition, the wear debris on the worn surfaces of GF/EPR are observed by a confocal scanning laser microscope. It is shown that the primary wear mechanism is the abrasive wear. The research results provide some design parameters for non-smooth surface, and the experiment results can serve as a beneficial supplement to non-smooth surface study.
基金Supported by National Natural Science Foundation of China(Grant No.51375421)Key Project of Science and Technology Research of Hebei Province,China(ZD20131027)
文摘Bionic non-smooth surface is widely applied in metal and ceramics materials. In order to introduce this technology to high pressure seawater pump, the influence of bionic non-smooth surface on the engineering plastics used in pump should be investigated. The comparative tests are carried out with a ring-on-disc configuration under 800, 1000, 1200 and 1400 r/min in order to research the influence of the bionic non-smooth surface on glass fiber-epoxy resin composite（GF/EPR） under natural seawater lubrication. The disc surfaces are textured with five kinds of pits, which are semi-spherical, conical, cone-cylinder combined, cylindrical pits and through holes, respectively. A smooth surface is tested as reference. The results show that the lubrication performance of dimpled GF/EPR sample is much better than that of the smooth sample under all rotational speeds. The semi-spherical pits surface has more obvious friction reduction than the others, which shows that the least reduction is approximately 43.29% of smooth surface under 1200 r/rain. However, the wear level is only marginally influenced by dimples. The surface morphology investigations disclose severe modifications caused by abrasive wear primarily. The results are helpful to vary friction properties of GF/EPR by non-smooth surface, or provide references to the design of non-smooth surfaces under certain condition.
基金supported by the National Natural Science Foundation of China(Nos.51971047 and 52271022)the project of Liaoning Province’s“Rejuvenating Liaoning talents plan”(No.XLYC1907046)+2 种基金Dalian High-Level Talent Innovation Support Program(No.2020RJ07)the State Key Lab of Advanced Metals and Materials(No.2021-ZD10)the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(No.2019JH3/30100032).
文摘Introducing ductile crystalline dendrites into a glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to improve the poor ductility of bulk metallic glasses(BMGs).However,the presence of soft crystalline phases tends to decrease the strength and causes the strength-ductility tradeoff.Here,relying on the flexible laser additive manufacturing(LAM)technique that allows the composition tailoring of each layer,we successfully fabricate a lamellated Zr-based BMGC constructed by the alternating superimposition of soft and hard layers.The lamellated BMGC shows an exceptional combination of yield strength(∼1.2 GPa)and ductility(∼5%).Such enhanced strength-ductility synergy is attributed to the asynchronous deformation at two scales,i.e.,inter-laminar and intra-laminar,and the unique dual-scale Ta particles that uniformly distribute on the amorphous matrix.The lamellated structure design motif,enabled by the flexible LAM technology,provides a new window for the development of high-performance BMGCs.It is also applicable to the synergistic enhancement of strength and plasticity of other brittle metallic materials.
基金B.Bartusch,H.Merker,N.Geiβler and B.Opitz for technical support,and L.Deng,P.Zhao for stimulating discussions.T.He and X.Han acknowledge the financial support from the China Scholarship Council(CSC).We acknowledge DESY(Hamburg,Germany),a member of the Helmholtz Association HGF,for the provision of experimental facilities.Parts of this research were carried out at PETRA III and we would like to thank Dr.Z.Hegedues and Dr.U.Lienert for assistance in using beamline P21.2.Beamtime was allocated for proposal I-20200178.
文摘The synthesis of martensitic or shape-memory bulk metallic glass composites(BMGCs)via solidification of the glass-forming melts requires the meticulous selection of the chemical composition and the proper choice of the processing parameters in order to ensure that the glassy matrix coexists with the desired amount of austenitic phase.Unfortunately,a relatively limited number of such systems,where austenite and glassy matrix coexist over a wide range of compositions,is available.Here,we study the effective-ness of powder metallurgy as an alternative to solidification for the synthesis of shape memory BMGCs.Zr_(48)Cu_(36)Al_(8)Ag_(8)matrix composites with different volume fractions of Ni_(50.6)Ti_(49.4)are fabricated using hot pressing and their microstructure,mechanical properties and deformation mechanism are investigated employing experiments and simulations.The results demonstrate that shape-memory BMGCs with tun-able microstructures and properties can be synthesized by hot pressing.The phase stability of the glass and austenitic components across a wide range of compositions allows us to examine fundamental as-pects in the field of shape memory BMGCs,including the effect of the confining stress on the martensitic transformation exerted by the glassy matrix,the contribution of each phase to the plasticity and the mechanism responsible for shear band formation.The present method gives a virtually infinite choice among the possible combinations of glassy matrices and shape memory phases,expanding the range of accessible shape memory BMGCs to systems where the glassy and austenitic phases do not form simul-taneously using the solidification route.
基金supported by Grant-In-Aid for Scientific Research(C)(No.19560689)
文摘The unusual glass-forming ability（GFA） of the Zr48Cu36Ag8Al8 alloy and the high ductility of the Zr48Cu36Ag8Al8 metallic glass-matrix composites containing Ta powder were reported.The bulk metallic glass rod with a diameter of 25 mm was successfully synthesized using copper mold casting for the Zr48Cu36Ag8Al8 alloy.High GFA of this alloy was found to be related to a large supercooled liquid region and a quaternary eutectic point with low melting temperature.The bulk metallic glass matrix composites were prepared by introducing extra Ta particles into the Zr48Cu36Ag8Al8 melt.The composites consist of Ta particles homogenously distributed in the Zr48Cu36Ag8Al8 metallic glass matrix.The optimum content of Ta powder is 10at%for the composite with the highest plasticity,which shows a plastic strain of 31%.
文摘Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.
文摘Using melt infiltration casting at different temperatures （965, 990 and 1015 °C） for different time （10 and 15 min）, the composites of （Cu50Zr43Al7）99.5Si0.5 bulk metallic glass reinforced with tungsten wires were produced. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and quasi-static compression tests were carried out to evaluate the microstructure and mechanical properties. The results show that the maximum ultimate compressive strength and strain-to-failure of about 1880 MPa and 16.7% were achieved, respectively, at the infiltration temperature of 965 °C for 15 min.
基金L.Deng acknowledges financial support by the Chinese Scholarship Council(CSC)support by German Research Foundation(DFG)(Nos.PA 2275/4-1,PA2275/6-1 and KO5771/1-1)+1 种基金support by the National Natural Science Foundation of China(Nos.51701213 and 51790484)the National key research and development program(2018YFB0703402)。
文摘Monolithic bulk metallic glass and glass matrix composites with a relative density above 98%were produced by processing Cu_(46)Zr_(46)Al_(8)(at.%)via selective laser melting(SLM).Their microstructures and mechanical properties were systematically examined.B2 CuZr nanocrystals(30-100 nm in diameter)are uniformly dispersed in the glassy matrix when SLM is conducted at an intermediate energy input.These B2 CuZr nanocrystals nucleate the oxygen-stabilized big cube phase during a remelting step.The presence of these nanocrystals increases the structural heterogeneity as indirectly revealed by mircrohardness and nanoindentation measurements.The corresponding maps in combination with calorimetric data indicate that the glassy phase is altered by the processing conditions.Despite the formation of crystals and a high overall free volume content,all additively manufactured samples fail at lower stress than the as-cast glass and without any plastic strain.The inherent brittleness is attributed to the presence of relatively large pores and the increased oxygen content after selective laser melting.
基金support from the National Natural Science Foundation of China (Nos. 51434008, U1435204, and 51531005)the China’s Manned Space Station Project (Mission No.: TGJZ800-2-RW024)the Shuangchuang Project of Jiangsu Province, China
文摘In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites（BMGCs）. The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_（47.5）Zr_（33）Cu_（5.8）Co_3Be_（12.5）（at.%） BMGC was studied by the secondary ion mass spectrometry（SIMS） and the electron energy loss spectroscopy（EELS）.It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained.
基金supported by the National Key Research and Development Plan of China(No.2018YFB0704101)the Fundamental Research Funds for the Central Universities(No.3102019ZX013)the Planning Programme of Shan Xi Province’s Co-Ordination and Innovation Project of Science and Technology(No.2016KTZDCY02-02)。
文摘In this study,non-toxic in-situβphases of reinforced Ti/Zr-based bulk metallic glass matrix composites(BMGCs)of(Ti_(0.65)Zr_(0.35))100-xCux(x=5,10,15 at.%)are fabricated via selective laser melting.The effect of Cu content on phase formation,microstructure,and mechanical properties is investigated.The average volume fraction and width of theβphase decreases with increasing Cu content,while a more amorphous phase and the(Ti,Zr)_(2)Cu phase forms.In the center zone of the molten pool,theβphase grows in the direction of the temperature gradient,and the amorphous phase distributes among theβphases.This occurs using:sphere morphology(for x=5),a more continuous elongated sphere and network morphology(for x=10),and network morphology(for x=15),respectively.In the edge zone of the molten pool,due to the smaller cooling rate and the existence of a partially molten zone,theβphase becomes coarser,and an amorphous phase forms for more continuous networks.Furthermore,the hardness improves significantly with increasing Cu content.No crack is found for x=5.Although the average volume fraction of theβphase for x=5 is about 90%,the compression yield strength is 1386±64 MPa,reaching to an average level of conventionally fabricated counterparts,due to finer microstructure,and twinning and martensitic transformation of theβphase.
