Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building ...Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.展开更多
Titanium matrix composite reinforced by graphene nanoplatelets(GNPs)was fabricated via powder metallurgy route.Hot isostatic pressing and hot extrusion were used to consolidate the mixed powder of GNPs and TC4 titaniu...Titanium matrix composite reinforced by graphene nanoplatelets(GNPs)was fabricated via powder metallurgy route.Hot isostatic pressing and hot extrusion were used to consolidate the mixed powder of GNPs and TC4 titanium(Ti)alloy.The microstructures,mechanical properties and sliding wear performance of Ti/GNPs composite had been researched to evaluate the rein forcing effect of GNPs on tita nium matrix.Microstructure observation indicates that GNPs could restrain grai n growth slightly in titanium matrix.Titanium matrix and graphene exhibit a clean and firm interface formed by means of metallurgical bonding on atomic scale.Compared with the monolithic titanium alloy,the composite with 1.2 vol.%GNPs exhibits significantly improved elastic modulus and strength.The sliding wear test shows that there is an obvious enhancement in the tribological performance of Ti/GNPs composite with 1.2 vol.%GNPs.The results of this work indicate that GNP is an efficient reinforcenient material in titanium matrix.The strengthening mechanism including precipitates strengthening,load transfer and grain refinement mechanism of GNPs in titanium matrix was discussed.A modified shear-lag model was used to analyze the reinforcement contribution of the stress transfer mechanism.The calculation shows that the stress load mechanism constitutes the main strengthening mechanism in Ti/GNPs composite.展开更多
In light of the burgeoning energy technology sector and the ever-growing demand for lithium across diverse industrial domains,conventional lithium extraction methods have been proven inadequate due to their limited pr...In light of the burgeoning energy technology sector and the ever-growing demand for lithium across diverse industrial domains,conventional lithium extraction methods have been proven inadequate due to their limited production capacity and high operational costs.This work introduces a novel approach to the manganese-titanium based composite HMTO(Mn:Ti=1:4)lithium ion-sieve(LIS)nanospheres,employing lithium acetate dihydrate,manganese carbonate and titanium dioxide P25 as the primary materials.These nanospheres exhibit relatively uniform spherical morphology,narrow size distribution,small average particle size(ca.55 nm),large specific surface area(43.58 m^(2)g^(-1))and high surface O_(2)-content(59.01%).When utilized as the adsorbents for Li^(+)ions,the HMTO(Mn:Ti=1:4)LIS demonstrates a fast adsorption rate,approaching equilibrium within 6.0 h with an equilibrium adsorption capacity(qe)of 79.5 mg g^(-1)and a maximum adsorption capacity(qm)of 87.26 mg g^(-1)(initial concentration CO:1.8 g L^(-1)).In addition,the HMTO(Mn:Ti=1:4)also delivers a high lithium extraction from the simulated high magnesium-lithium molar ratio salt lake brine(Mg:Li=103),achieving a qeof 33.85 mg g^(-1)along with a remarkable selectivity(α_(Mg)^(Li)=2192.76).Particularly,the HMTO(Mn:Ti=1:4)LIS showcases a satisfactory recycling adsorption performance.The adsorption capacity remains at a high level,even that determined after the 5th cycle(55.45 mg g^(-1))surpasses that of the most recently reported adsorbents.Ultimately,the fantastic synergistic lithium adsorption mechanism is deliberately uncovered by leveraging the ion exchange principles and molecular dynamics(MD)simulations.展开更多
A porous yttrium oxide crucible with both thermal shock resistance and erosion resistance was developed by structural optimization.The structure-optimized yttrium oxide crucible was proved to be suitable for melting h...A porous yttrium oxide crucible with both thermal shock resistance and erosion resistance was developed by structural optimization.The structure-optimized yttrium oxide crucible was proved to be suitable for melting highly reactive titanium alloys.Low-cost(TiB+Y2O_(3))-reinforced titanium matrix composites were prepared by vacuum induction melting using the prepared crucible.The thermal deformation behavior and microstructure evolution of(TiB+Y2O_(3))-reinforced tita-nium matrix composites were investigated at deformation temperatures of 900-1100℃with strain rates of 0.001-1 s-1.The results showed that the prepared yttrium oxide crucible had both thermal shock and erosion resistance,the low-cost titanium matrix composites could be prepared by the developed yttrium oxide crucibles which were homogeneous in composition and highly sensitive to strain rate and deformation temperature,and the peak and theological stresses decreased with increasing deformation temperature or decreasing strain rate.In addition,the average thermal deformation activation energy of the composites was calculated to be 574.6 kJ/mol by establishing the Arrhenius constitutive equation in consideration of the strain variables,and the fitting goodness between the predicted stress value and the measured value was 97.624%.The calculated analysis of the hot processing map showed that the best stable thermal deformation zone was located in the deformation temperature range of 1000-1100℃and strain rate range of 0.001-0.01 s^(-1),where the peak dissipation coefficient wasη=71%.In this zone,the deformation of the reinforcement and matrix was harmonious,the reinforcement was less likely to fracture,dynamic recrystallization occurred more fully and the alloy exhibited near steady rheological characteristics.展开更多
The oxidation behavior of Ti55 alloy and TiBw/Ti55 composites at temperatures ranging from 960 to 1000℃ was investigated by characterizing the surface and cross-section microstructure of specimens.Results showed that...The oxidation behavior of Ti55 alloy and TiBw/Ti55 composites at temperatures ranging from 960 to 1000℃ was investigated by characterizing the surface and cross-section microstructure of specimens.Results showed that TiBw reinforcement accelerated the occurrence of Ti_(6O)/Ti_(3O) by dissolving oxygen in titanium in the starting oxidation stage,and the Ti_(6O)/Ti_(3O) transformed into TiO_(2) with the progression of oxidation.Meanwhile,TiBw reinforcement promoted the formation of(101)crystal planes to be beneficial to the growth of TiO_(2) twins.The cross-sectional characterization showed that the oxide layer of Ti55 alloy and TiBw/Ti55 composites from outside to inside was TiO_(2)+Al_(2)O_(3),TiO_(2),Ti-Sn compounds,Ti_(6O)/Ti_(3O) in sequence,which was confirmed by calculating the standard Gibbs free energy of the oxide nucleation.The TiBw reinforcement accelerated the occurrence of suboxides Ti_(6O)/Ti_(3O) by dissolving oxygen in titanium,and promoted the formation of(101)crystal planes which were beneficial to the growth of TiO_(2) twins.The optimal addition of TiBw induced the TiO_(2) twins,promoted the random orientation of oxides and refined the oxide size of the TiBw/Ti55 composites with 3.5%volume fractions of TiBw,resulting in the best resistance against oxidation.展开更多
Graphene is considered promising reinforcement for improving the mechanical properties of the titanium alloys.However,overcoming the strength-ductility trade-off in graphene-reinforced titanium composites remains a ch...Graphene is considered promising reinforcement for improving the mechanical properties of the titanium alloys.However,overcoming the strength-ductility trade-off in graphene-reinforced titanium composites remains a challenge.In this study,the high-performance graphene nanoplatelets(GNPs)reinforced Ti-6Al-4V(TC4)matrix composites were successfully synthesized by combining the hot-pressing sintering and hot-rolling methods.Studies on the effect of GNPs on microstructures and properties of the as-sintered and as-rolled TC4 composites were systematically conducted.It indicates that the strength of the composites can be substantially enhanced by the addition of GNPs,primarily attributable to grain refinement and the pinning effect induced by in situ formed TiC particles.Moreover,the increase in the GNPs content results in a decrease in the plasticity of the as-sintered composites due to the aggregation of TiC.Additionally,hot rolling synchronously enhances the strength and plasticity of the composites by facilitating the homogeneous dispersion of TiC within the TC4 matrix.This work provided a potential strategy in designing the graphene-reinforced TC4 matrix composites with superior strength-ductility synergy.展开更多
In order to achieve the strength-ductility synergy and improve the work-hardening capacity,Ti64 based composites with dispersive nanoscaled TiB whiskers inside grains were fabricated by plasma rotating electrode proce...In order to achieve the strength-ductility synergy and improve the work-hardening capacity,Ti64 based composites with dispersive nanoscaled TiB whiskers inside grains were fabricated by plasma rotating electrode process coupled with spark plasma sintering.Based on the rapid eutectic reaction,the nanoscaled TiB whiskers exhibited ultra-fine network distribution in composite powders.During the spark plasma sintering process,the network dissolved,and TiB followed the Ostwald ripening mechanism and merged along the(100)plane.The intragranular TiB whiskers could significantly refine the primaryβgrain andαlath.The ultimate tensile strength of the composite with only 2 vol.%TiB whiskers was enhanced to(1123±17)MPa while the elongation was similar to that of the as-sintered Ti64 alloy with approximately 8%.The strength-ductility synergy effect was mainly attributed to the significant grain refinement and the work-hardening ability improvement contributed by intragranular nanoscaled TiB.展开更多
To assess the high-temperature creep properties of titanium matrix composites for aircraft skin,the TA15 alloy,TiB/TA15 and TiB/(TA15−Si)composites with network structure were fabricated using low-energy milling and v...To assess the high-temperature creep properties of titanium matrix composites for aircraft skin,the TA15 alloy,TiB/TA15 and TiB/(TA15−Si)composites with network structure were fabricated using low-energy milling and vacuum hot pressing sintering techniques.The results show that introducing TiB and Si can reduce the steady-state creep rate by an order of magnitude at 600℃ compared to the alloy.However,the beneficial effect of Si can be maintained at 700℃ while the positive effect of TiB gradually diminishes due to the pores near TiB and interface debonding.The creep deformation mechanism of the as-sintered TiB/(TA15−Si)composite is primarily governed by dislocation climbing.The high creep resistance at 600℃ can be mainly attributed to the absence of grain boundaryαphases,load transfer by TiB whisker,and the hindrance of dislocation movement by silicides.The low steady-state creep rate at 700℃ is mainly resulted from the elimination of grain boundaryαphases as well as increased dynamic precipitation of silicides andα_(2).展开更多
The effects of current pulsing on the microstructure, hardness and tensile properties at different temperatures of gas tungsten arc （GTA） weldments of titanium matrix composites were studied. Full-penetration butt j...The effects of current pulsing on the microstructure, hardness and tensile properties at different temperatures of gas tungsten arc （GTA） weldments of titanium matrix composites were studied. Full-penetration butt joints were made with or without current pulsing. Optical microscopy, hardness test and scanning electron microscopy were employed to evaluate the metallurgical characteristics of welded joints. Tensile properties of weldments at different temperatures were studied and correlated with the microstructure. The results exhibit that current pulsing leads to the refinement of the weld microstrucmre and TiB whisker and the redistribution of reinforcements resulting in higher hardness, tensile strength and ductility of weldments in the as-welded condition.展开更多
Laser cladding experiments were done on a 5-kW continuous wave CO2 laser to synthesize TiC and TiB rein- fowed titanium matrix composite coatings on Ti-6AI-4V alloy with a mixture of Ti and B4C precursor powder. The t...Laser cladding experiments were done on a 5-kW continuous wave CO2 laser to synthesize TiC and TiB rein- fowed titanium matrix composite coatings on Ti-6AI-4V alloy with a mixture of Ti and B4C precursor powder. The ther- modynamics of the reactions were calculated and analyzed. The microstructure and phase evolution of TiB and TiC com- posites were investigated. The results showed that the chemical reaction between Ti and B4C would release much heat, and these compounds, TiC, TiB, and small amount of TiB2, can be formed on the surface of Ti-6AI-4V alloy if the supplied en- ergy is sufficient to excite the reaction among the initial products. A good metallurgical bond between the coating and the substrate can be achieved. The microhardness of coating was irregular and the maximum value was approximately HV600.展开更多
In-situ TiC and remained multi-walled carbon nanotubes（MWCNTs） reinforced Ti composites were synthesized using vacuum hot-press sintering and hot rolling. The effect of weight fraction of MWCNTs on microstructural e...In-situ TiC and remained multi-walled carbon nanotubes（MWCNTs） reinforced Ti composites were synthesized using vacuum hot-press sintering and hot rolling. The effect of weight fraction of MWCNTs on microstructural evolution and mechanical properties of the Ti composites was investigated. The results indicated that both proportion and particle size of TiC increased in proportion to MWCNTs content, which resulted in different matrix microstructure, and the grains were obviously refined after rolling deformation. The hardness tests indicated that MWCNTs addition could make the composites harden, and 18.4%improvement in hardness was obtained after hot rolling. The significant improvement in both strength and hardness could be attributed to grain refinement, solid solution strengthening of carbon and dispersion strengthening of TiC particles and remained MWCNTs. A good combination of strength and ductility were achieved in Ti–1 wt% MWCNTs composites, which were in accordance with the uniform distribution of smaller-sized TiC particles in Ti matrix.展开更多
In order to elucidate the microstructure evolution and silicide precipitation behavior during high-temperature deformation,TiB reinforced titanium matrix composites were subjected to isothermal hot compression at 950...In order to elucidate the microstructure evolution and silicide precipitation behavior during high-temperature deformation,TiB reinforced titanium matrix composites were subjected to isothermal hot compression at 950℃,strain rate of 0.05 s^(−1) and employing different strains of 0.04,0.40,0.70 and 1.00.The results show that with the increase of strain,a decrease in the content,dynamic recrystallization of theαphase and the vertical distribution of TiB along the compression axis lead to stress stability.Meantime,continuous dynamic recrystallization reduces the orientation difference of the primaryαphase,which weakens the texture strength of the matrix.The recrystallization mechanisms are strain-induced grain boundary migration and particle stimulated nucleation by TiB.The silicide of Ti_(6)Si_(3) is mainly distributed at the interface of TiB andαphase.The precipitation of silicide is affected by element diffusion,and TiB whisker accelerates the precipitation behavior of silicide by hindering the movement of dislocations and providing nucleation particles.展开更多
This work focused on the influence of TiC reinforcing particles on the tribological properties of titanium matrix composites(TMCs)with open porosity,processed by spark plasma sintering(SPS).Materials composed of an eq...This work focused on the influence of TiC reinforcing particles on the tribological properties of titanium matrix composites(TMCs)with open porosity,processed by spark plasma sintering(SPS).Materials composed of an equimolar mixture of Ti and TiH2 with 0,3,10 and 30 vol.% of TiC were sintered at 850 ℃.Nanoindentation and wear tests were carried out to assess the nanohardness and the wear resistance in a tribometer with a reciprocating sliding ball-on-flat configuration.Results showed a nanohardness increment from 5 to 14 GPa with increasing TiC content.The coefficient of friction(CoF)showed a minimum of 0.2 for 10% TiC grade,which also showed the lowest wear rate.For the low TiC content sample,adhesive wear with severe plastic deformation was identified.Meanwhile,medium content TiC sample showed a mechanical mixed layer(MML),whereas high TiC content composite showed abrasive as the main wear mechanism.In conclusion,the wear mechanisms,CoFs and wear volume changed with TiC content.展开更多
To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder ...To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder as the cladding material.The microstructure,phase structure and properties of the coatings were analyzed by SEM,XRD,EPMA,TEM,hardness tester and fretting wear meter.It was observed that the outer ring of the network-like structure was mainly TiB strengthening phase,while the inner ring was α-Ti grain,and the interface between TiB and Ti matrix was very clean and had a consistent orientation relationship.The hardness of the cladding layer with network-like structure gradually decreased from the surface toward the interface,but the average hardness was nearly two times that of the substrate.In the fretting wear test,it was found that the wear resistance of the cladding layer with network-like structure was larger than that of the substrate under low load(40 N).The results revealed that the hardness and fretting wear resistance of the titanium-based composite coating could be improved by the introduction of network-like structure.展开更多
Further improvement on high temperature durability is one of the most important aims except for high specific strength, high specific stiffness, and excellent wear resistance, to design and fabricate discontinuously r...Further improvement on high temperature durability is one of the most important aims except for high specific strength, high specific stiffness, and excellent wear resistance, to design and fabricate discontinuously reinforced titanium matrix composites （DRTMCs）. Their superior properties render them extensive application potential in aerospace and military industries due to the urgent demand for the materials with characteristics of lightweight, high strength, high stiffness and high temperature durability. With development on fabrication methods and room temperature properties, testing, characterizing, evaluating and further increasing high temperature properties of DRTMCs are becoming more and more important to promote their applications. This review provides insights and comprehensions on the high temperature tensile properties, superplastic tensile properties, creep behaviors, and high temperature oxidation behaviors of DRTMCs,展开更多
Two types of titanium/steel composite plates with the same thickness were manufactured by parallel explosive welding and double vertical explosive welding and rolling, respectively. The comparative analysis of microst...Two types of titanium/steel composite plates with the same thickness were manufactured by parallel explosive welding and double vertical explosive welding and rolling, respectively. The comparative analysis of microstructure showed that the interface of double vertical explosive welding plate （B plate） tended to be straight while the interface of parallel explosive welding plate （A plate） was wavy bonding. Defects near the interface of B plate were extruded, and the thickness of the diffusion layer of B plate was thicker under the effects of preheating temperature and press-working. Comparative tests of mechanical properties indicated that the tensile shear strength of B plate was lower while its micro-hardness was higher. Specimens of these two types of plates were neither separated nor cracked after bending up to 180° in the three-point bending test. From the microstructural observation of tensile fracture characteristics, A plate had strong toughness fracture while B plate had mainly ductile fracture with cleavage fracture as the supplement. Macroscopically, the tensile strength of the latter was 7.9% less than that of the former. However, both satisfied the Chinese standard of tensile strength.展开更多
Considerable studies on processed pure titanium and titanium alloys have proved the possibility of prop-erty anisotropy induced by crystallographic textures,but limited information is available for the intrinsic coupl...Considerable studies on processed pure titanium and titanium alloys have proved the possibility of prop-erty anisotropy induced by crystallographic textures,but limited information is available for the intrinsic coupling of matrix and reinforcement textures and their synergistic effect on property anisotropy in tita-nium matrix composite(TMCs).In the present work,an advanced EBSD/EDS coupling method was used to investigate the formation mechanism of primaryαand secondaryαtextures in the matrix alloy.It is revealed for the first time that the reinforcement TiB_(w)displays a{100}<010>texture after hot rolling and has little effect on the matrix texture component but weakens texture intensity.Significant anisotropies in the tensile strength and ductility can be all noted at room and high-temperatures,which is the syn-ergistic effect of the matrix texture and the aligned TiB_(w).The mean Schmid factor of each slip system was calculated to evaluate the influence of matrix texture on the minimum active stress of slip deforma-tion in the different tensile directions.The analysis shows that the strong T-type matrix texture results in higher strength but lower ductility when loaded in the transverse direction.Moreover,a generalized shear-lag model was modified to quantitatively evaluate the strengthening contribution of aligned TiB_(w),which decreases with increasing off-axis angle and test temperature.A new parameter,defined as the critical aspect ratio of the off-axis whisker,was proposed to rationalize why the TiB_(w) failure mechanism converts from TiB_(w) fracture to TiB_(w)/matrix interfacial debonding with increasing off-axis angle and test temperature.展开更多
The wear tests of titanium matrix composites(TMCs)at the loads of 50,100,120,and 150 N were carried out with an MMW-1 vertical universal friction and wear tester to study the addition of multilayer graphene(MLG)/nano-...The wear tests of titanium matrix composites(TMCs)at the loads of 50,100,120,and 150 N were carried out with an MMW-1 vertical universal friction and wear tester to study the addition of multilayer graphene(MLG)/nano-Fe2O3 composites(0,0.1,0.2,0.3,0.4,and 0.5 g)on the dry sliding wear behavior of TMCs.TMCs presented a marked variation in wear loss as a function of the amount of MLG/Fe2O3 addition,and a significant decrease in the friction coefficient was obtained,reducing this parameter up to 50%.With the rise and fall of wear loss,TMCs underwent a transition from severe wear to mild wear.These phenomena were attributed to the existence of a protective lubricating film,which prevented the surface from coming in direct contact,and the lubricating film was 15-20μm thick and made up of MLG/Fe2O3(1:2)nanocomposites.Its structure was speculated to be similar to a rolling wood.展开更多
Titanium metal matrix composites （TiMMCs） reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre （MCF） metho...Titanium metal matrix composites （TiMMCs） reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre （MCF） method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing （VHP）. In contrast to most of existing studies, the fibre, arrangement has been carefully controlled either in square or hexagonal arrays throughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.展开更多
The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical re...The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical reaction between elements or between elements and compounds. Using the approach, contamination at the composite matrix/reinforcement particle interface did not occur, interface bonding was good, and the reinforcement particle was thermodynamically stable. The stage of development of the preparation process for in situ TMCs as well as the thermodynamic analysis of the possible in situ reaction systems was described.展开更多
文摘Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.
基金National Natural Science Foundation of China(51802296)Beijing Municipal Science and Technology Commission(Z171100002017016,Z191100005619006).
文摘Titanium matrix composite reinforced by graphene nanoplatelets(GNPs)was fabricated via powder metallurgy route.Hot isostatic pressing and hot extrusion were used to consolidate the mixed powder of GNPs and TC4 titanium(Ti)alloy.The microstructures,mechanical properties and sliding wear performance of Ti/GNPs composite had been researched to evaluate the rein forcing effect of GNPs on tita nium matrix.Microstructure observation indicates that GNPs could restrain grai n growth slightly in titanium matrix.Titanium matrix and graphene exhibit a clean and firm interface formed by means of metallurgical bonding on atomic scale.Compared with the monolithic titanium alloy,the composite with 1.2 vol.%GNPs exhibits significantly improved elastic modulus and strength.The sliding wear test shows that there is an obvious enhancement in the tribological performance of Ti/GNPs composite with 1.2 vol.%GNPs.The results of this work indicate that GNP is an efficient reinforcenient material in titanium matrix.The strengthening mechanism including precipitates strengthening,load transfer and grain refinement mechanism of GNPs in titanium matrix was discussed.A modified shear-lag model was used to analyze the reinforcement contribution of the stress transfer mechanism.The calculation shows that the stress load mechanism constitutes the main strengthening mechanism in Ti/GNPs composite.
基金supported by the National Natural Science Foundation of China(22075304,22378390)Natural Science Foundation of Shandong Province,China(ZR2022MB075)+2 种基金State Key Laboratory of Organic-Inorganic Composites(oic-202401016)State Key Laboratory of Chemical Engineering(SKL-ChE-24A02)Beijing Natural Science Foundation,China(3222050).
文摘In light of the burgeoning energy technology sector and the ever-growing demand for lithium across diverse industrial domains,conventional lithium extraction methods have been proven inadequate due to their limited production capacity and high operational costs.This work introduces a novel approach to the manganese-titanium based composite HMTO(Mn:Ti=1:4)lithium ion-sieve(LIS)nanospheres,employing lithium acetate dihydrate,manganese carbonate and titanium dioxide P25 as the primary materials.These nanospheres exhibit relatively uniform spherical morphology,narrow size distribution,small average particle size(ca.55 nm),large specific surface area(43.58 m^(2)g^(-1))and high surface O_(2)-content(59.01%).When utilized as the adsorbents for Li^(+)ions,the HMTO(Mn:Ti=1:4)LIS demonstrates a fast adsorption rate,approaching equilibrium within 6.0 h with an equilibrium adsorption capacity(qe)of 79.5 mg g^(-1)and a maximum adsorption capacity(qm)of 87.26 mg g^(-1)(initial concentration CO:1.8 g L^(-1)).In addition,the HMTO(Mn:Ti=1:4)also delivers a high lithium extraction from the simulated high magnesium-lithium molar ratio salt lake brine(Mg:Li=103),achieving a qeof 33.85 mg g^(-1)along with a remarkable selectivity(α_(Mg)^(Li)=2192.76).Particularly,the HMTO(Mn:Ti=1:4)LIS showcases a satisfactory recycling adsorption performance.The adsorption capacity remains at a high level,even that determined after the 5th cycle(55.45 mg g^(-1))surpasses that of the most recently reported adsorbents.Ultimately,the fantastic synergistic lithium adsorption mechanism is deliberately uncovered by leveraging the ion exchange principles and molecular dynamics(MD)simulations.
基金supported by the National Natural Science Foundation of China(52071065)the Fundamental Research Funds for the Central Universities(N2007007)+1 种基金the National Key R&D Program of China(2016YFB-0301201)the Ten Technology Research Projects of Hunan Province(No.2022GK1050).
文摘A porous yttrium oxide crucible with both thermal shock resistance and erosion resistance was developed by structural optimization.The structure-optimized yttrium oxide crucible was proved to be suitable for melting highly reactive titanium alloys.Low-cost(TiB+Y2O_(3))-reinforced titanium matrix composites were prepared by vacuum induction melting using the prepared crucible.The thermal deformation behavior and microstructure evolution of(TiB+Y2O_(3))-reinforced tita-nium matrix composites were investigated at deformation temperatures of 900-1100℃with strain rates of 0.001-1 s-1.The results showed that the prepared yttrium oxide crucible had both thermal shock and erosion resistance,the low-cost titanium matrix composites could be prepared by the developed yttrium oxide crucibles which were homogeneous in composition and highly sensitive to strain rate and deformation temperature,and the peak and theological stresses decreased with increasing deformation temperature or decreasing strain rate.In addition,the average thermal deformation activation energy of the composites was calculated to be 574.6 kJ/mol by establishing the Arrhenius constitutive equation in consideration of the strain variables,and the fitting goodness between the predicted stress value and the measured value was 97.624%.The calculated analysis of the hot processing map showed that the best stable thermal deformation zone was located in the deformation temperature range of 1000-1100℃and strain rate range of 0.001-0.01 s^(-1),where the peak dissipation coefficient wasη=71%.In this zone,the deformation of the reinforcement and matrix was harmonious,the reinforcement was less likely to fracture,dynamic recrystallization occurred more fully and the alloy exhibited near steady rheological characteristics.
基金supported by the Special Project of the Central-Guided Local Science and Technology Development(Grant No.2022ZY2-JCYJ-01-06)the Key Research and Development Program(Grant No.2020-xxx-ZD-179-00-05)Prof.Lujun Huang Group at Harbin Institute of Technology for providing the TiBw/Ti55 composites.
文摘The oxidation behavior of Ti55 alloy and TiBw/Ti55 composites at temperatures ranging from 960 to 1000℃ was investigated by characterizing the surface and cross-section microstructure of specimens.Results showed that TiBw reinforcement accelerated the occurrence of Ti_(6O)/Ti_(3O) by dissolving oxygen in titanium in the starting oxidation stage,and the Ti_(6O)/Ti_(3O) transformed into TiO_(2) with the progression of oxidation.Meanwhile,TiBw reinforcement promoted the formation of(101)crystal planes to be beneficial to the growth of TiO_(2) twins.The cross-sectional characterization showed that the oxide layer of Ti55 alloy and TiBw/Ti55 composites from outside to inside was TiO_(2)+Al_(2)O_(3),TiO_(2),Ti-Sn compounds,Ti_(6O)/Ti_(3O) in sequence,which was confirmed by calculating the standard Gibbs free energy of the oxide nucleation.The TiBw reinforcement accelerated the occurrence of suboxides Ti_(6O)/Ti_(3O) by dissolving oxygen in titanium,and promoted the formation of(101)crystal planes which were beneficial to the growth of TiO_(2) twins.The optimal addition of TiBw induced the TiO_(2) twins,promoted the random orientation of oxides and refined the oxide size of the TiBw/Ti55 composites with 3.5%volume fractions of TiBw,resulting in the best resistance against oxidation.
基金supported by the National Key Research and Development Program of China(No.2023YFB3711000)the National Natural Science Foundation of China(Nos.52403364,52404369,W2411048 and 52171164)+3 种基金the Youth Innovation Promotion Association CAS(No.2021188)the Excellent Youth Fund of Liaoning Province(No.2024JH3/10200022)the China Postdoctoral Science Foundation(No.2024M753302)the IMR Innovation Fund(No.2024-PY18).
文摘Graphene is considered promising reinforcement for improving the mechanical properties of the titanium alloys.However,overcoming the strength-ductility trade-off in graphene-reinforced titanium composites remains a challenge.In this study,the high-performance graphene nanoplatelets(GNPs)reinforced Ti-6Al-4V(TC4)matrix composites were successfully synthesized by combining the hot-pressing sintering and hot-rolling methods.Studies on the effect of GNPs on microstructures and properties of the as-sintered and as-rolled TC4 composites were systematically conducted.It indicates that the strength of the composites can be substantially enhanced by the addition of GNPs,primarily attributable to grain refinement and the pinning effect induced by in situ formed TiC particles.Moreover,the increase in the GNPs content results in a decrease in the plasticity of the as-sintered composites due to the aggregation of TiC.Additionally,hot rolling synchronously enhances the strength and plasticity of the composites by facilitating the homogeneous dispersion of TiC within the TC4 matrix.This work provided a potential strategy in designing the graphene-reinforced TC4 matrix composites with superior strength-ductility synergy.
基金supported by the National Key R&D Program of China(No.2022YFB3707402)the National Natural Science Foundation of China(Nos.52301189,U22A20113)the Natural Science Foundation of Heilongjiang Province,China(No.LH2023E031).
文摘In order to achieve the strength-ductility synergy and improve the work-hardening capacity,Ti64 based composites with dispersive nanoscaled TiB whiskers inside grains were fabricated by plasma rotating electrode process coupled with spark plasma sintering.Based on the rapid eutectic reaction,the nanoscaled TiB whiskers exhibited ultra-fine network distribution in composite powders.During the spark plasma sintering process,the network dissolved,and TiB followed the Ostwald ripening mechanism and merged along the(100)plane.The intragranular TiB whiskers could significantly refine the primaryβgrain andαlath.The ultimate tensile strength of the composite with only 2 vol.%TiB whiskers was enhanced to(1123±17)MPa while the elongation was similar to that of the as-sintered Ti64 alloy with approximately 8%.The strength-ductility synergy effect was mainly attributed to the significant grain refinement and the work-hardening ability improvement contributed by intragranular nanoscaled TiB.
基金financially supported by the National Key R&D Program of China(No.2022YFB3707405)the National Natural Science Foundation of China(Nos.U22A20113,52171137,52071116)+1 种基金Heilongjiang Provincial Natural Science Foundation,China(No.TD2020E001)Heilongjiang Touyan Team Program,China.
文摘To assess the high-temperature creep properties of titanium matrix composites for aircraft skin,the TA15 alloy,TiB/TA15 and TiB/(TA15−Si)composites with network structure were fabricated using low-energy milling and vacuum hot pressing sintering techniques.The results show that introducing TiB and Si can reduce the steady-state creep rate by an order of magnitude at 600℃ compared to the alloy.However,the beneficial effect of Si can be maintained at 700℃ while the positive effect of TiB gradually diminishes due to the pores near TiB and interface debonding.The creep deformation mechanism of the as-sintered TiB/(TA15−Si)composite is primarily governed by dislocation climbing.The high creep resistance at 600℃ can be mainly attributed to the absence of grain boundaryαphases,load transfer by TiB whisker,and the hindrance of dislocation movement by silicides.The low steady-state creep rate at 700℃ is mainly resulted from the elimination of grain boundaryαphases as well as increased dynamic precipitation of silicides andα_(2).
基金Project(51371114)supported by the National Natural Science Foundation of ChinaProject(2012CB619600)supported by the National Basic Research Program of China+1 种基金Project(10SG15)supported by the Dawn Program of Shanghai Education Commission,ChinaProject(12XD1402800)supported by Shanghai Science and Technology Committee,China
文摘The effects of current pulsing on the microstructure, hardness and tensile properties at different temperatures of gas tungsten arc （GTA） weldments of titanium matrix composites were studied. Full-penetration butt joints were made with or without current pulsing. Optical microscopy, hardness test and scanning electron microscopy were employed to evaluate the metallurgical characteristics of welded joints. Tensile properties of weldments at different temperatures were studied and correlated with the microstructure. The results exhibit that current pulsing leads to the refinement of the weld microstrucmre and TiB whisker and the redistribution of reinforcements resulting in higher hardness, tensile strength and ductility of weldments in the as-welded condition.
基金financially supported by the National "973" Research Project (No. 2006CB605206-1)
文摘Laser cladding experiments were done on a 5-kW continuous wave CO2 laser to synthesize TiC and TiB rein- fowed titanium matrix composite coatings on Ti-6AI-4V alloy with a mixture of Ti and B4C precursor powder. The ther- modynamics of the reactions were calculated and analyzed. The microstructure and phase evolution of TiB and TiC com- posites were investigated. The results showed that the chemical reaction between Ti and B4C would release much heat, and these compounds, TiC, TiB, and small amount of TiB2, can be formed on the surface of Ti-6AI-4V alloy if the supplied en- ergy is sufficient to excite the reaction among the initial products. A good metallurgical bond between the coating and the substrate can be achieved. The microhardness of coating was irregular and the maximum value was approximately HV600.
基金supported financially by the National Natural Science Foundation of China (Nos. 51371114, 51501112 and U1602274)the Fund of the State Key Laboratory of Solidification Processing in NWPU (No. SKLSP201620)+2 种基金the Shanghai Academy of Spaceflight-Joint Research Centre of Shanghai Jiao Tong University advanced aerospace technology (No. US-CAST2012-14)the National Engineering and Research Center for Commercial Aircraft Manufacturing (No. SAMC14-JS-15-047)the 111 Project (No. B16032)
文摘In-situ TiC and remained multi-walled carbon nanotubes（MWCNTs） reinforced Ti composites were synthesized using vacuum hot-press sintering and hot rolling. The effect of weight fraction of MWCNTs on microstructural evolution and mechanical properties of the Ti composites was investigated. The results indicated that both proportion and particle size of TiC increased in proportion to MWCNTs content, which resulted in different matrix microstructure, and the grains were obviously refined after rolling deformation. The hardness tests indicated that MWCNTs addition could make the composites harden, and 18.4%improvement in hardness was obtained after hot rolling. The significant improvement in both strength and hardness could be attributed to grain refinement, solid solution strengthening of carbon and dispersion strengthening of TiC particles and remained MWCNTs. A good combination of strength and ductility were achieved in Ti–1 wt% MWCNTs composites, which were in accordance with the uniform distribution of smaller-sized TiC particles in Ti matrix.
基金financial supports from the National Natural Science Foundation of China (No. 51871184)the Natural Science Foundation of Shandong Province, China (No. ZR2019MEM037)+1 种基金the Zhoucun School-City Integration Development Plan, China (No. 2020ZCXCZH03)the School-city Integration Development Project of Zibo, China (No. 2019ZBXC022)。
文摘In order to elucidate the microstructure evolution and silicide precipitation behavior during high-temperature deformation,TiB reinforced titanium matrix composites were subjected to isothermal hot compression at 950℃,strain rate of 0.05 s^(−1) and employing different strains of 0.04,0.40,0.70 and 1.00.The results show that with the increase of strain,a decrease in the content,dynamic recrystallization of theαphase and the vertical distribution of TiB along the compression axis lead to stress stability.Meantime,continuous dynamic recrystallization reduces the orientation difference of the primaryαphase,which weakens the texture strength of the matrix.The recrystallization mechanisms are strain-induced grain boundary migration and particle stimulated nucleation by TiB.The silicide of Ti_(6)Si_(3) is mainly distributed at the interface of TiB andαphase.The precipitation of silicide is affected by element diffusion,and TiB whisker accelerates the precipitation behavior of silicide by hindering the movement of dislocations and providing nucleation particles.
基金The Mexican Council of Science and Technology (CONACYT) for the support received under the scholarship (449474)
文摘This work focused on the influence of TiC reinforcing particles on the tribological properties of titanium matrix composites(TMCs)with open porosity,processed by spark plasma sintering(SPS).Materials composed of an equimolar mixture of Ti and TiH2 with 0,3,10 and 30 vol.% of TiC were sintered at 850 ℃.Nanoindentation and wear tests were carried out to assess the nanohardness and the wear resistance in a tribometer with a reciprocating sliding ball-on-flat configuration.Results showed a nanohardness increment from 5 to 14 GPa with increasing TiC content.The coefficient of friction(CoF)showed a minimum of 0.2 for 10% TiC grade,which also showed the lowest wear rate.For the low TiC content sample,adhesive wear with severe plastic deformation was identified.Meanwhile,medium content TiC sample showed a mechanical mixed layer(MML),whereas high TiC content composite showed abrasive as the main wear mechanism.In conclusion,the wear mechanisms,CoFs and wear volume changed with TiC content.
基金Projects(2019J01813,2018J01557) supported by the Natural Science Foundation of Fujian Province,ChinaProject(2018H0031) supported by the Guiding Science Program of Fujian Province,ChinaProject(2018GP2002) supported by the Science and Technology Program of Putian City,China
文摘To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder as the cladding material.The microstructure,phase structure and properties of the coatings were analyzed by SEM,XRD,EPMA,TEM,hardness tester and fretting wear meter.It was observed that the outer ring of the network-like structure was mainly TiB strengthening phase,while the inner ring was α-Ti grain,and the interface between TiB and Ti matrix was very clean and had a consistent orientation relationship.The hardness of the cladding layer with network-like structure gradually decreased from the surface toward the interface,but the average hardness was nearly two times that of the substrate.In the fretting wear test,it was found that the wear resistance of the cladding layer with network-like structure was larger than that of the substrate under low load(40 N).The results revealed that the hardness and fretting wear resistance of the titanium-based composite coating could be improved by the introduction of network-like structure.
基金financially supported by the National Natural Science Foundation of China (Nos.51101042,51271064 and 51471063)the High Technology Research and Development Program of China (No.2013AA031202)the Fundamental Research Funds for the Central Universities (No.HIT.BRETIII.201401)
文摘Further improvement on high temperature durability is one of the most important aims except for high specific strength, high specific stiffness, and excellent wear resistance, to design and fabricate discontinuously reinforced titanium matrix composites （DRTMCs）. Their superior properties render them extensive application potential in aerospace and military industries due to the urgent demand for the materials with characteristics of lightweight, high strength, high stiffness and high temperature durability. With development on fabrication methods and room temperature properties, testing, characterizing, evaluating and further increasing high temperature properties of DRTMCs are becoming more and more important to promote their applications. This review provides insights and comprehensions on the high temperature tensile properties, superplastic tensile properties, creep behaviors, and high temperature oxidation behaviors of DRTMCs,
基金This project was sponsored by the National Natural Science Foundation of China （No. 51541112） and Special Fund Achievement Transformation Projects in Jiangsu of China （No. BA2012030）.
文摘Two types of titanium/steel composite plates with the same thickness were manufactured by parallel explosive welding and double vertical explosive welding and rolling, respectively. The comparative analysis of microstructure showed that the interface of double vertical explosive welding plate （B plate） tended to be straight while the interface of parallel explosive welding plate （A plate） was wavy bonding. Defects near the interface of B plate were extruded, and the thickness of the diffusion layer of B plate was thicker under the effects of preheating temperature and press-working. Comparative tests of mechanical properties indicated that the tensile shear strength of B plate was lower while its micro-hardness was higher. Specimens of these two types of plates were neither separated nor cracked after bending up to 180° in the three-point bending test. From the microstructural observation of tensile fracture characteristics, A plate had strong toughness fracture while B plate had mainly ductile fracture with cleavage fracture as the supplement. Macroscopically, the tensile strength of the latter was 7.9% less than that of the former. However, both satisfied the Chinese standard of tensile strength.
基金financially supported by the National Natural Scienc e Foundation of China(Nos.U1602274,51875349,51871150 and 51821001)the National Key R&D Program of China(No.2018YFB1106403)+2 种基金the Medical Intersection Project of Shanghai Jiao Tong University(Nos.ZH2018QNA22 and YG2017QN28)the 111 Project(No.B16032)the Laboratory Innovative Research Pro-gram of Shanghai Jiao Tong University(No.17SJ-14).
文摘Considerable studies on processed pure titanium and titanium alloys have proved the possibility of prop-erty anisotropy induced by crystallographic textures,but limited information is available for the intrinsic coupling of matrix and reinforcement textures and their synergistic effect on property anisotropy in tita-nium matrix composite(TMCs).In the present work,an advanced EBSD/EDS coupling method was used to investigate the formation mechanism of primaryαand secondaryαtextures in the matrix alloy.It is revealed for the first time that the reinforcement TiB_(w)displays a{100}<010>texture after hot rolling and has little effect on the matrix texture component but weakens texture intensity.Significant anisotropies in the tensile strength and ductility can be all noted at room and high-temperatures,which is the syn-ergistic effect of the matrix texture and the aligned TiB_(w).The mean Schmid factor of each slip system was calculated to evaluate the influence of matrix texture on the minimum active stress of slip deforma-tion in the different tensile directions.The analysis shows that the strong T-type matrix texture results in higher strength but lower ductility when loaded in the transverse direction.Moreover,a generalized shear-lag model was modified to quantitatively evaluate the strengthening contribution of aligned TiB_(w),which decreases with increasing off-axis angle and test temperature.A new parameter,defined as the critical aspect ratio of the off-axis whisker,was proposed to rationalize why the TiB_(w) failure mechanism converts from TiB_(w) fracture to TiB_(w)/matrix interfacial debonding with increasing off-axis angle and test temperature.
基金The authors would like to acknowledge the financial support of this work by National Natural Science Foundation of China(No.51505199)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_1670).
文摘The wear tests of titanium matrix composites(TMCs)at the loads of 50,100,120,and 150 N were carried out with an MMW-1 vertical universal friction and wear tester to study the addition of multilayer graphene(MLG)/nano-Fe2O3 composites(0,0.1,0.2,0.3,0.4,and 0.5 g)on the dry sliding wear behavior of TMCs.TMCs presented a marked variation in wear loss as a function of the amount of MLG/Fe2O3 addition,and a significant decrease in the friction coefficient was obtained,reducing this parameter up to 50%.With the rise and fall of wear loss,TMCs underwent a transition from severe wear to mild wear.These phenomena were attributed to the existence of a protective lubricating film,which prevented the surface from coming in direct contact,and the lubricating film was 15-20μm thick and made up of MLG/Fe2O3(1:2)nanocomposites.Its structure was speculated to be similar to a rolling wood.
文摘Titanium metal matrix composites （TiMMCs） reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre （MCF） method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing （VHP）. In contrast to most of existing studies, the fibre, arrangement has been carefully controlled either in square or hexagonal arrays throughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50205005)
文摘The in situ synthesis method for titanium matrix composites （TMCs） has obvious technical and economical advantages over other traditional methods. Ultrafine reinforcement particles were formed in situ by chemical reaction between elements or between elements and compounds. Using the approach, contamination at the composite matrix/reinforcement particle interface did not occur, interface bonding was good, and the reinforcement particle was thermodynamically stable. The stage of development of the preparation process for in situ TMCs as well as the thermodynamic analysis of the possible in situ reaction systems was described.
