BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechan...BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BNp content, relative density and Vickers＇ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BNp content which is mainly determined by the density, crystal structure and atomic number of the elements.展开更多
In order to study the performance of ceramic composite projectile penetrating into ceramic composite target,the contrast test and numerical simulations of the penetration of standard projectile and the ceramic composi...In order to study the performance of ceramic composite projectile penetrating into ceramic composite target,the contrast test and numerical simulations of the penetration of standard projectile and the ceramic composite projectile into a ceramic composite target were conducted.The results show that the penetration performance of ceramic composite projectile is obvious superior to that of standard projectile for ceramic composite target.The ceramic nose of ceramic composite projectile fully destroys the ceramic panels anterior to its following armor-piercing projectile body,thus maintaining the penetration ability of the following armor-piercing projectile body.展开更多
SiC foam ceramic reinforced aluminum matrix composites(SFCAMCs)were prepared by squeeze casting aluminum alloy(Al-23Si)into the SiC foam ceramic with different pore sizes,and the corrosion behavior of the SFCAMCs was ...SiC foam ceramic reinforced aluminum matrix composites(SFCAMCs)were prepared by squeeze casting aluminum alloy(Al-23Si)into the SiC foam ceramic with different pore sizes,and the corrosion behavior of the SFCAMCs was studied in NaCl solutions.Static immersion corrosion tests were conducted at 20°C,50°C and 80°C,respectively.Corrosion morphology and products were analyzed by scanning electron microscope,energy dispersive system and X-ray diffraction.It was found that the corrosion rate of SFCAMCs increases as the temperature rising,and the bigger pore size of SiC foam ceramic reinforcement,the better corrosion resistance of SFCAMCs.展开更多
Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes o...Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.展开更多
Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influenc...Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influence of carbide ceramics(B_(4)C,SiC,TiC)as reinforcements,in improving reciprocating tribology performance and mechanical strength of A333 hybrid composites against alloy.Hollow cylindrical samples of A333/6 wt%B_(4)C/4 wt%TiC and A333/6 wt%B_(4)C/4 wt%SiC hybrid FGMMCs were developed using horizontal centrifugal casting.Metallography analysis on both composites revealed increasing ceramic gradient distribution towards outer composite wall.Particle rich zone of A333/B_(4)C/SiC hybrid FGMMC showed maximum micro-hardness(198.9 HV)and tensile strength(267.9 MPa).Elemental mapping confirmed effective distribution of ceramics and detected elemental composition of both composites.Particle rich layer of A333/B_(4)C/SiC hybrid FGMMC exhibited improved wear resistance in comparison with all three layers of A333/B_(4)C/TiC hybrid FGMMC and alloy.Third-body abrasion and tribo-chemical wear were the predominant mechanisms revealed for both composites during worn surface analysis.展开更多
A new style Ni-containing alumina ceramic foam based continuous three-dimensional interconnected skeleton was prepared by impregnating a polymeric sponge with aqueous ceramic slurry.Subsequently,alumina ceramic foam/s...A new style Ni-containing alumina ceramic foam based continuous three-dimensional interconnected skeleton was prepared by impregnating a polymeric sponge with aqueous ceramic slurry.Subsequently,alumina ceramic foam/steel metal matrix composites(MMCs) were prepared successfully by sand mold casting technique.The microstructure and mechanical properties of MMCs were investigated by SEM,EDS and compressive test.The results show that the depth of infiltration is about 40 μm to the bonding interface of ceramic/steel and the fracture strength σmax and plastic strain limit εp of composite are 520 MPa and 11.2%,respectively.The fretting wear mechanism of MMCs is mainly performed at the oxidative wear mode with lower load/friction frequency and the predominant oxidation wear together with slight adhesive wear and abrasive wear multiple mode with higher load/ friction frequency.Moreover,the infiltration bonding and continuous three-dimensional interconnected ceramic skeleton play a vital role in the stability of the bonding interface and excellent mechanical properties.展开更多
Compared with conventional materials,the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance.In this paper,an active and a passive coolin...Compared with conventional materials,the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance.In this paper,an active and a passive cooling refractory composite specimens are designed and tested with an experimental facility composed of multilayer smale scale cooling penel which consists of a water cooling system and a ceramic matrix composite specimen,and a gas generator used for providing lower and higher transfer rate gases to simulate the temperatures in combustion chamber of ramjst.The active cooling specimen can continuously suffer high surface temperature of 2 000 K for 30 s and that of 3 000 K for 9.3 s,respectively.The experiment results show that the active cooling composite structure is available for high-temperature condition in ramjet.展开更多
The precursor infiltration and pyrolysis（PIP） method for preparation of BN/SiO2 composites was used to improve mechanical properties, dielectric properties and feasibility of high temperature dielectric parts with l...The precursor infiltration and pyrolysis（PIP） method for preparation of BN/SiO2 composites was used to improve mechanical properties, dielectric properties and feasibility of high temperature dielectric parts with large dimensions and complex shapes. In the processing procedure, the porous BN ceramic matrix was first successfully prepared by compacting the mixed powders of B and BN and then sintering them at a certain temperature under normal pressure of N2.The polycarbosilane（PCS） solution was vacuum infiltrated into porous BN ceramics at the room temperature and then at 800℃ in the air to depolimerize out amorphous SiO2, and sintered further at 1300℃ in N2 to get BN/SiO2 composites. The microstructure of materials was studied by means of X-ray diffraction and electron probe micro （analysis.） The thermo-decomposition mechanism of PCS was investigated by a TG-DTA and infrared （IR） spectrum analysis. The flexural strengths were measured by the three-point bending method. The dielectric constant and the loss tangent were measured by the wave-guide method. The results show BN/SiO2 composites were fabricated. The obtained composites posses a flexural strength of 61.96-93.31MPa, the dielectric constant in the range of 3.50-3.78 and the order of magnitude of the loss tangent at 10-3, which are good for the high temperature dielectric parts with large size and complex shapes.展开更多
Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is use...Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.展开更多
基金Project(HIT.NSRIF.2010112)supported by the Fundamental Research Fund for the Central Universities,ChinaProjects(50902030,51021002)supported by the National Natural Science Foundation of China
文摘BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BNp content, relative density and Vickers＇ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BNp content which is mainly determined by the density, crystal structure and atomic number of the elements.
文摘In order to study the performance of ceramic composite projectile penetrating into ceramic composite target,the contrast test and numerical simulations of the penetration of standard projectile and the ceramic composite projectile into a ceramic composite target were conducted.The results show that the penetration performance of ceramic composite projectile is obvious superior to that of standard projectile for ceramic composite target.The ceramic nose of ceramic composite projectile fully destroys the ceramic panels anterior to its following armor-piercing projectile body,thus maintaining the penetration ability of the following armor-piercing projectile body.
基金Project(00008713)supported by the Program of the Science and Technology Creative Team of Universities in Jiangxi,ChinaProject(2013-KLP-04)supported by the Open Foundation of Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials,China
文摘SiC foam ceramic reinforced aluminum matrix composites(SFCAMCs)were prepared by squeeze casting aluminum alloy(Al-23Si)into the SiC foam ceramic with different pore sizes,and the corrosion behavior of the SFCAMCs was studied in NaCl solutions.Static immersion corrosion tests were conducted at 20°C,50°C and 80°C,respectively.Corrosion morphology and products were analyzed by scanning electron microscope,energy dispersive system and X-ray diffraction.It was found that the corrosion rate of SFCAMCs increases as the temperature rising,and the bigger pore size of SiC foam ceramic reinforcement,the better corrosion resistance of SFCAMCs.
基金Projects(212006065,21666018)supported by the National Natural Science Foundation of China
文摘Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.
文摘Aluminium hybrid functionally graded metal matrix composites(FGMMCs),meet growing demands for supreme tribo-mechanical performance in automotive and aviation industry.This research experimentally compares the influence of carbide ceramics(B_(4)C,SiC,TiC)as reinforcements,in improving reciprocating tribology performance and mechanical strength of A333 hybrid composites against alloy.Hollow cylindrical samples of A333/6 wt%B_(4)C/4 wt%TiC and A333/6 wt%B_(4)C/4 wt%SiC hybrid FGMMCs were developed using horizontal centrifugal casting.Metallography analysis on both composites revealed increasing ceramic gradient distribution towards outer composite wall.Particle rich zone of A333/B_(4)C/SiC hybrid FGMMC showed maximum micro-hardness(198.9 HV)and tensile strength(267.9 MPa).Elemental mapping confirmed effective distribution of ceramics and detected elemental composition of both composites.Particle rich layer of A333/B_(4)C/SiC hybrid FGMMC exhibited improved wear resistance in comparison with all three layers of A333/B_(4)C/TiC hybrid FGMMC and alloy.Third-body abrasion and tribo-chemical wear were the predominant mechanisms revealed for both composites during worn surface analysis.
基金Project(51271080) supported by the National Natural Science Foundation of ChinaProject(2012JSSPITP1968) supported by the Innovative Foundation for Students of Jiangsu Province,ChinaProject(CKJB201204) supported by the Innovation Fund of Nanjing Institute of Technology,China
文摘A new style Ni-containing alumina ceramic foam based continuous three-dimensional interconnected skeleton was prepared by impregnating a polymeric sponge with aqueous ceramic slurry.Subsequently,alumina ceramic foam/steel metal matrix composites(MMCs) were prepared successfully by sand mold casting technique.The microstructure and mechanical properties of MMCs were investigated by SEM,EDS and compressive test.The results show that the depth of infiltration is about 40 μm to the bonding interface of ceramic/steel and the fracture strength σmax and plastic strain limit εp of composite are 520 MPa and 11.2%,respectively.The fretting wear mechanism of MMCs is mainly performed at the oxidative wear mode with lower load/friction frequency and the predominant oxidation wear together with slight adhesive wear and abrasive wear multiple mode with higher load/ friction frequency.Moreover,the infiltration bonding and continuous three-dimensional interconnected ceramic skeleton play a vital role in the stability of the bonding interface and excellent mechanical properties.
文摘Compared with conventional materials,the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance.In this paper,an active and a passive cooling refractory composite specimens are designed and tested with an experimental facility composed of multilayer smale scale cooling penel which consists of a water cooling system and a ceramic matrix composite specimen,and a gas generator used for providing lower and higher transfer rate gases to simulate the temperatures in combustion chamber of ramjst.The active cooling specimen can continuously suffer high surface temperature of 2 000 K for 30 s and that of 3 000 K for 9.3 s,respectively.The experiment results show that the active cooling composite structure is available for high-temperature condition in ramjet.
文摘The precursor infiltration and pyrolysis（PIP） method for preparation of BN/SiO2 composites was used to improve mechanical properties, dielectric properties and feasibility of high temperature dielectric parts with large dimensions and complex shapes. In the processing procedure, the porous BN ceramic matrix was first successfully prepared by compacting the mixed powders of B and BN and then sintering them at a certain temperature under normal pressure of N2.The polycarbosilane（PCS） solution was vacuum infiltrated into porous BN ceramics at the room temperature and then at 800℃ in the air to depolimerize out amorphous SiO2, and sintered further at 1300℃ in N2 to get BN/SiO2 composites. The microstructure of materials was studied by means of X-ray diffraction and electron probe micro （analysis.） The thermo-decomposition mechanism of PCS was investigated by a TG-DTA and infrared （IR） spectrum analysis. The flexural strengths were measured by the three-point bending method. The dielectric constant and the loss tangent were measured by the wave-guide method. The results show BN/SiO2 composites were fabricated. The obtained composites posses a flexural strength of 61.96-93.31MPa, the dielectric constant in the range of 3.50-3.78 and the order of magnitude of the loss tangent at 10-3, which are good for the high temperature dielectric parts with large size and complex shapes.
基金the Projects Nos. III.23.2.3 (I.S. Konovalenko, S.P. Buyakova) and III.23.2.4 (S.G. Psakhie) of the Basic Scientific Research Program of State Academies of Sciences for 2013e2020the RFBR Project No. 12-01-00805-a (A.Yu. Smolin, E.V. Shilko)the grant No. 14-19-00718 of the Russian Science Foundation (A.Yu. Smolin, E.V. Shilko, S.V. Astafurov)
文摘Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.
