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
A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic gla...A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering stage.However,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by NS.The TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/BMGCs.Quasi-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of Wp.When the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering necks.This makes the fracture mode of Wp/BMGCs being predominantly transgranular fracture.However,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more prominent.The aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular fracture.Additionally,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.展开更多
The low porosity of metal-organic framework glass makes it difficult to prepare membranes with high permeability.To solve this problem,we fabricated a series of self-supported zeolite glass composite membranes with di...The low porosity of metal-organic framework glass makes it difficult to prepare membranes with high permeability.To solve this problem,we fabricated a series of self-supported zeolite glass composite membranes with different 4A zeolite loadings using the abundant pore structure of the zeolite.The 4A zeolite embedded in the zeolite glass composite membrane preserved the ligand bonds and chemical structure.The self-supported zeolite glass composite membranes exhibited good interfacial compatibility.More importantly,the incorporation of the 4A zeolite significantly improved the CO_(2)adsorption capacity of the pure a_(g)ZIF-62 membranes.In addition,gas separation performance measurements showed that the(a_(g)ZIF-62)_(0.7)(4A)_(0.3)membrane had a permeability of 13,329 Barrer for pure CO_(2)and an ideal selectivity of 31.7 for CO_(2)/CH_(4),which exceeded Robeson's upper bound.The(a_(g)ZIF-62)_(0.7)(4A)_(0.3)membrane exhibited good operational stability in the variable pressure test and 48 h long-term continuous test.This study provides a method for preparing zeolite glass composite membranes.展开更多
The constraint factor,C,defined as hardness,H,to the yield strength,σ_(y),ratio,is an indirect measure of the pressure sensitivity in materials.Previous investigations determined that while C is less than 3 for cryst...The constraint factor,C,defined as hardness,H,to the yield strength,σ_(y),ratio,is an indirect measure of the pressure sensitivity in materials.Previous investigations determined that while C is less than 3 for crystalline materials,and remains invariant with change in temperature,it is greater than 3 for bulk metallic glasses(BMGs)and increases with increasing temperature,below their glass transition temper-ature,T_(g).In this study,the variations in C for two BMG composites(BMGCs),which have an amorphous matrix and in situ precipitated crystallineβ-Ti dendrites,which in one case transforms under stress toα”-Ti and deforms by slip in the other,as a function of temperature are examined and compared with that of a BMG.For this purpose,instrumented indentation tests,with a Berkovich tip,and uniaxial com-pression tests were performed to measure the H andσ_(y),respectively,on all alloys and their constituents at temperatures in the range of 0.48 T_(g) and 0.75 T_(g).σ_(y) and H of the BMGC with transforming dendrites(BMGC-T)increase and remain invariant with increasing temperature,respectively.Alternately,in BMG and the BMGC with non-transforming dendrites(BMGC–NT),the same properties decrease with increas-ing temperature.BMGC-T has the highest C of∼4.93 whereas that of BMGC–NT and BMG are∼3.72 and∼3.28,respectively,at 0.48 T_(g).With increasing temperature,C of the BMG and BMGC–NT increases with temperature,but that of the BMGC-T decreases.The values of C and their variations as a function of temperature were explained by studying the variation of pressure sensitivity of the amorphous phase and concluding that the plastic flow in BMGCs under constrained conditions,such as indentation,is con-trolled by the flow resistance of the amorphous matrix whereas that in uniaxial compression,which is only partially constrained,is controlled by plasticity in both the dendrites and matrix.展开更多
The glass-forming ability and mechanical properties of metallic glasses and their composites are well known to be sensitive to the preparation conditions and are highly deteriorated by industrial preparing conditions ...The glass-forming ability and mechanical properties of metallic glasses and their composites are well known to be sensitive to the preparation conditions and are highly deteriorated by industrial preparing conditions such as low-purity raw materials and low vacuum.Here,we showed that a series of in-situ bulk metallic glass composites(BMGCs)which exhibit excellent ductility and segmental work hardening were successfully developed utilizing a high vacuum high-pressure die casting(HV-HPDC)technology along with industrial-grade raw materials.The tensile properties of these BMGCs are systematically investigated and correlated with the alloy microstructure.As compared with the copper mold suction casting method,the volume fraction difference of the dendrite phase for the BMGCs with the same composition is not significant when fabricated by the HV-HPDC,whereas the size of theβ-phase is generally larger.Insitu BMGCs with the composition of Ti_(48)Zr_(20)(V_(12/17)Cu_(5/17))19 Be 13 obtained by the HV-HPDC process show ductility up to 11.3%under tension at room temperature and exhibit a certain amount of work hardening.Two conditions need to be met to enable the BMGCs,which are prepared by vacuum die-casting to retain favorable ductility:(1)The volume fraction ofβphase stays below 62%±2%;(2)The equiaxed crystals with a more uniform size in the range of 5-10μm.Meanwhile,the results of the present study provided guidance for developing BMGCs with good ductile properties under industrial conditions.展开更多
Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and geometry.Nevertheless,the BMGs prepared ...Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and geometry.Nevertheless,the BMGs prepared by LPBF usually suffered from less plasticity and poorer fracture toughness as compared to their cast counterparts due to partial crystallization in heat-affected zones(HAZs).Since crystallization in HAZs is hard to avoid completely in LPBF BMGs,it is desirable to design a suitable alloy system,in which only ductile crystalline phase,instead of brittle intermetallics,is formed in HAZs.This unique structure could effectively increase the toughness/plasticity of the LPBF BMGs.To achieve this goal,a quaternary BMG system with a composition of Zr_(47.5)Cu_(45.5)Al_(5)Co_(2)is adopted and subjected to LPBF.It is found that nearly a single phase of B_(2)-ZrCu is precipitated in HAZs,while a fully amorphous phase is formed in molten pools(MPs).This B_(2)phase reinforced BMG composite exhibits excellent mechanical properties with enhanced plasticity and toughness.Furthermore,it is easy to modulate the mechanical properties by altering the amount of the B_(2)phase via adjusting the laser energy input.Finally,the best combination of strength,plasticity,and notch toughness is obtained in the BMG composite containing 27.4%B_(2)phase and 72.6%amorphous phase,which exhibits yield strength(σ_(s))of 1423 MPa,plastic strain(ε_(p))of 4.65%,and notch toughness(K_(q))of 53.9 MPa m 1/2.Furthermore,a notable strain-hardening is also observed.The improvement of plasticity/toughness and appearance of strain-hardening behavior are mainly due to the martensite phase transformation from the B_(2)phase to the Cm phase during plastic deformation(i.e.,the phase transformation-induced plasticity effect).The current work provides a guide for making advanced BMGs and BMG composites by additive manufacturing.展开更多
Introducing soft crystalline phases into the glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to enhance the ductility of bulk metallic glasses(BMGs).However,the introduction of soft c...Introducing soft crystalline phases into the glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to enhance the ductility of bulk metallic glasses(BMGs).However,the introduction of soft crystalline phases severely sacrifices the strength,resulting in the strength-ductility trade-off.To defeat this dilemma,here,we successfully fabricate a bioinspired BMGC with architecture mimicking a porcupine fish spine.The bioinspired BMGC shows a pronounced yield strength of∼800 MPa with an excellent fracture strain of∼35%.The fabrication of the bioinspired BMGC is achieved through infiltration and vitrification of molten Zr50 Ti5 Cu27 Ni10 Al8(Zr50)melt into the crystalline Nb skeleton fabricated by laser additive manufacturing(LAM).Such enhanced strength-ductility synergy is attributed to the asynchronous deformation associated with the delicate bioinspired heterogeneous architecture.The bioinspired structural design motif,enabled by the combination of LAM and infiltration casting technologies,opens a new window to develop high-performance BMGCs on a large scale for structural applications.展开更多
In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in har...In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.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
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financially supported by the National Natural Science Foundation of China(Nos.52371154,52090043,52175371 and 52271147)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012158)+1 种基金the Knowledge Innovation Program of Wuhan-Basic Researchthe Fundamental Research Funds for the Central Universities(No.2021GCRC003)。
文摘A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering stage.However,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by NS.The TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/BMGCs.Quasi-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of Wp.When the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering necks.This makes the fracture mode of Wp/BMGCs being predominantly transgranular fracture.However,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more prominent.The aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular fracture.Additionally,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.
基金supported by the S&T Program of Hebei(no.22373709D).
文摘The low porosity of metal-organic framework glass makes it difficult to prepare membranes with high permeability.To solve this problem,we fabricated a series of self-supported zeolite glass composite membranes with different 4A zeolite loadings using the abundant pore structure of the zeolite.The 4A zeolite embedded in the zeolite glass composite membrane preserved the ligand bonds and chemical structure.The self-supported zeolite glass composite membranes exhibited good interfacial compatibility.More importantly,the incorporation of the 4A zeolite significantly improved the CO_(2)adsorption capacity of the pure a_(g)ZIF-62 membranes.In addition,gas separation performance measurements showed that the(a_(g)ZIF-62)_(0.7)(4A)_(0.3)membrane had a permeability of 13,329 Barrer for pure CO_(2)and an ideal selectivity of 31.7 for CO_(2)/CH_(4),which exceeded Robeson's upper bound.The(a_(g)ZIF-62)_(0.7)(4A)_(0.3)membrane exhibited good operational stability in the variable pressure test and 48 h long-term continuous test.This study provides a method for preparing zeolite glass composite membranes.
基金support provided by the Science and Engineering Research Board,Department of Science&Technology(No.SRG/2020/000095)the Prime Minister Fellowship(PMRF)(No.PMRF/2021/1401226)+2 种基金support of the National Natural Science Foundation of China(No.52171164)the National Key Laboratory of Science and Technology on Materials under Shock and Impact(No.WDZC2022–13)the Youth Innovation Promotion Association CAS(No.2021188).
文摘The constraint factor,C,defined as hardness,H,to the yield strength,σ_(y),ratio,is an indirect measure of the pressure sensitivity in materials.Previous investigations determined that while C is less than 3 for crystalline materials,and remains invariant with change in temperature,it is greater than 3 for bulk metallic glasses(BMGs)and increases with increasing temperature,below their glass transition temper-ature,T_(g).In this study,the variations in C for two BMG composites(BMGCs),which have an amorphous matrix and in situ precipitated crystallineβ-Ti dendrites,which in one case transforms under stress toα”-Ti and deforms by slip in the other,as a function of temperature are examined and compared with that of a BMG.For this purpose,instrumented indentation tests,with a Berkovich tip,and uniaxial com-pression tests were performed to measure the H andσ_(y),respectively,on all alloys and their constituents at temperatures in the range of 0.48 T_(g) and 0.75 T_(g).σ_(y) and H of the BMGC with transforming dendrites(BMGC-T)increase and remain invariant with increasing temperature,respectively.Alternately,in BMG and the BMGC with non-transforming dendrites(BMGC–NT),the same properties decrease with increas-ing temperature.BMGC-T has the highest C of∼4.93 whereas that of BMGC–NT and BMG are∼3.72 and∼3.28,respectively,at 0.48 T_(g).With increasing temperature,C of the BMG and BMGC–NT increases with temperature,but that of the BMGC-T decreases.The values of C and their variations as a function of temperature were explained by studying the variation of pressure sensitivity of the amorphous phase and concluding that the plastic flow in BMGCs under constrained conditions,such as indentation,is con-trolled by the flow resistance of the amorphous matrix whereas that in uniaxial compression,which is only partially constrained,is controlled by plasticity in both the dendrites and matrix.
基金supported by the National Key Research and Development Plan(Grant Nos.2018YFA0703603,2021YFA0716302)Guangdong Major Project of Basic and Applied Basic Research,China(Grant Nos.2019B030302010,2020B1515120092)+2 种基金Guangdong Basic and Applied Basic Research Foundation,China(Grant Nos.2020B1515120092,2019B030302010)the National Natural Science Foundation of China(Grant Nos.52192602,52192603,51971092,11790291,and 61888102)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000).
文摘The glass-forming ability and mechanical properties of metallic glasses and their composites are well known to be sensitive to the preparation conditions and are highly deteriorated by industrial preparing conditions such as low-purity raw materials and low vacuum.Here,we showed that a series of in-situ bulk metallic glass composites(BMGCs)which exhibit excellent ductility and segmental work hardening were successfully developed utilizing a high vacuum high-pressure die casting(HV-HPDC)technology along with industrial-grade raw materials.The tensile properties of these BMGCs are systematically investigated and correlated with the alloy microstructure.As compared with the copper mold suction casting method,the volume fraction difference of the dendrite phase for the BMGCs with the same composition is not significant when fabricated by the HV-HPDC,whereas the size of theβ-phase is generally larger.Insitu BMGCs with the composition of Ti_(48)Zr_(20)(V_(12/17)Cu_(5/17))19 Be 13 obtained by the HV-HPDC process show ductility up to 11.3%under tension at room temperature and exhibit a certain amount of work hardening.Two conditions need to be met to enable the BMGCs,which are prepared by vacuum die-casting to retain favorable ductility:(1)The volume fraction ofβphase stays below 62%±2%;(2)The equiaxed crystals with a more uniform size in the range of 5-10μm.Meanwhile,the results of the present study provided guidance for developing BMGCs with good ductile properties under industrial conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.52192604 and 52201181)the Key R&D Program of Hubei(No.2022BAA023).
文摘Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and geometry.Nevertheless,the BMGs prepared by LPBF usually suffered from less plasticity and poorer fracture toughness as compared to their cast counterparts due to partial crystallization in heat-affected zones(HAZs).Since crystallization in HAZs is hard to avoid completely in LPBF BMGs,it is desirable to design a suitable alloy system,in which only ductile crystalline phase,instead of brittle intermetallics,is formed in HAZs.This unique structure could effectively increase the toughness/plasticity of the LPBF BMGs.To achieve this goal,a quaternary BMG system with a composition of Zr_(47.5)Cu_(45.5)Al_(5)Co_(2)is adopted and subjected to LPBF.It is found that nearly a single phase of B_(2)-ZrCu is precipitated in HAZs,while a fully amorphous phase is formed in molten pools(MPs).This B_(2)phase reinforced BMG composite exhibits excellent mechanical properties with enhanced plasticity and toughness.Furthermore,it is easy to modulate the mechanical properties by altering the amount of the B_(2)phase via adjusting the laser energy input.Finally,the best combination of strength,plasticity,and notch toughness is obtained in the BMG composite containing 27.4%B_(2)phase and 72.6%amorphous phase,which exhibits yield strength(σ_(s))of 1423 MPa,plastic strain(ε_(p))of 4.65%,and notch toughness(K_(q))of 53.9 MPa m 1/2.Furthermore,a notable strain-hardening is also observed.The improvement of plasticity/toughness and appearance of strain-hardening behavior are mainly due to the martensite phase transformation from the B_(2)phase to the Cm phase during plastic deformation(i.e.,the phase transformation-induced plasticity effect).The current work provides a guide for making advanced BMGs and BMG composites by additive manufacturing.
基金supported by the National Key Research and Development Program of China under Grant No.2023YFB3408101the National Natural Science Foundation of China under Grant Nos.52171164 and 52271022the Youth Innovation Promotion Association CAS(No.2021188).
文摘Introducing soft crystalline phases into the glassy matrix to produce bulk metallic glass composites(BMGCs)is an effective way to enhance the ductility of bulk metallic glasses(BMGs).However,the introduction of soft crystalline phases severely sacrifices the strength,resulting in the strength-ductility trade-off.To defeat this dilemma,here,we successfully fabricate a bioinspired BMGC with architecture mimicking a porcupine fish spine.The bioinspired BMGC shows a pronounced yield strength of∼800 MPa with an excellent fracture strain of∼35%.The fabrication of the bioinspired BMGC is achieved through infiltration and vitrification of molten Zr50 Ti5 Cu27 Ni10 Al8(Zr50)melt into the crystalline Nb skeleton fabricated by laser additive manufacturing(LAM).Such enhanced strength-ductility synergy is attributed to the asynchronous deformation associated with the delicate bioinspired heterogeneous architecture.The bioinspired structural design motif,enabled by the combination of LAM and infiltration casting technologies,opens a new window to develop high-performance BMGCs on a large scale for structural applications.
文摘In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.
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.
