We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surf...We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.展开更多
To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments...To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.展开更多
The influences of rolling reduction and aluminum sheet initial thickness(AIT)on the thickness fluctuation of aluminum layer(TFA)of embedded aluminum?steel composite sheet produced by cold roll bonding were investigate...The influences of rolling reduction and aluminum sheet initial thickness(AIT)on the thickness fluctuation of aluminum layer(TFA)of embedded aluminum?steel composite sheet produced by cold roll bonding were investigated,the formation mechanism of TFA was analyzed and method to improve the thickness uniformity of the aluminum layer was proposed.The results showed that when the reduction increased,TFA increased gradually.When the reduction was lower than40%,AIT had negligible effect on the TFA,while TFA increased with the decrease of AIT when the reduction was higher than40%.The non-uniformities of the steel surface deformation and the interfacial bonding extent caused by the work-hardened steel surface layer,were the main reasons for the formation of TFA.Adopting an appropriate surface treatment can help to decrease the hardening extent of the steel surface for improving the deformation uniformity during cold roll bonding process,which effectively improved the aluminum thickness uniformity of the embedded aluminum/steel composite sheets.展开更多
In this paper,the stresses and buckling behaviors of a thick-walled mi-cro sandwich panel with a flexible foam core and carbon nanotube reinforced composite(CNTRC)face sheets are considered based on the high-order she...In this paper,the stresses and buckling behaviors of a thick-walled mi-cro sandwich panel with a flexible foam core and carbon nanotube reinforced composite(CNTRC)face sheets are considered based on the high-order shear deformation theory(HSDT)and the modified couple stress theory(MCST).The governing equations of equi-librium are obtained based on the total potential energy principle.The effects of various parameters such as the aspect ratio,elastic foundation,temperature changes,and volume fraction of the canbon nanotubes(CNTs)on the critical buckling loads,normal stress,shear stress,and deflection of the thick-walled micro cylindrical sandwich panel consider-ing different distributions of CNTs are examined.The results are compared and validated with other studies,and showing an excellent compatibility.CNTs have become very use-ful and common candidates in sandwich structures,and they have been extensively used in many applications including nanotechnology,aerospace,and micro-structures.This paper also extends further applications of reinforced sandwich panels by providing the modified equations and formulae.展开更多
To provide a new idea to reduce anisotropy for sheets in the thickness direction by microstructure modification and,mean-while,maintain or even enhance tensile performance,the in-situ ZrB2 particle/AA7085 composite sh...To provide a new idea to reduce anisotropy for sheets in the thickness direction by microstructure modification and,mean-while,maintain or even enhance tensile performance,the in-situ ZrB2 particle/AA7085 composite sheets with thicknesses of 1,2,3,and 6 mm were investigated.The as-cast grain size was significantly refined by the heterogeneous nucleus of the ZrB2 particle.The microstructure results show that severe hot deformation converts as-cast disordered microstructure into a sequential microstructure by crushing the remanent phases and matrix into a fiber structure.After the solid solution and aging heat treatment,the composite sheets exhibit largely recrystallized grains compared with partially recrystallized grains in the matrix sheets,and weak or even free texture exists in the composite.The grain size in the composite sheets decreases with the increase in thickness reductions.For the thickness range of 1-3 mm,the composite sheets maintain a similar tensile per-formance as that in matrix sheets,while the strength and ductility in the 6-mm-thick composite sheet are improved.展开更多
The feasibility of preparing Fe/Cu composite sheet was achieved by introducing submillimeter thickness Al sheet as an interlayer by rolling at room temperature.The shear test of the composite sheet supported that the ...The feasibility of preparing Fe/Cu composite sheet was achieved by introducing submillimeter thickness Al sheet as an interlayer by rolling at room temperature.The shear test of the composite sheet supported that the metallurgical bonding strength between Fe/(Al)/Cu interface was stronger than that of Cu sheet at the initial state.With further 300 or 600℃ annealing treatments,the interlayer subsequently exhibited brittle shear fracture,and the shear strength significantly dropped under the shear test.Furthermore,the tensile test pointed out that the tensile fracture mechanism changed from fracture as a whole structure to interlayer-to-layer delamination mode after annealing treatment.The microstructure and X-ray diffraction observations proved that the formation of Cu–Al intermetallic compounds(IMCs)along the interlayer resulted in brittle fracture,rather than that of Fe–Al IMCs after annealing,especially under 600℃ annealing treatment.The investigation of the effect of the rolling process and annealing treatment on the mechanical properties of the Fe/(Al)/Cu composite sheet shall provide instruction for high-quality composite metallic sheet fabrication.展开更多
Electrochemical and localized corrosion behavior of a 4045/7072/3003 M/4045 Al alloy composite in 3.5 wt.%NaCl solution was investigated from cross-sectional and plane directions by electrochemical impedance spectrosc...Electrochemical and localized corrosion behavior of a 4045/7072/3003 M/4045 Al alloy composite in 3.5 wt.%NaCl solution was investigated from cross-sectional and plane directions by electrochemical impedance spectroscopy,polarization curves,and high-resolution microscopic examination.Plane directions showed higher corrosion resistance than the cross-sectional surface,with almost all localized corrosion initiated from Si-containing inclusions.The cross-section showed a complex galvanic effect among the four layers,the galvanic coupling between 4045/7072 accelerated the dissolution of 7072 because 7072 served as the anode,however,the galvanic coupling between 3003 M/4045 protected 4045 from corrosion,indicating that 3003 M served as the anode.展开更多
Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced. To create cold weld between A1 and Ag, mating surfaces were specially prepared and various rolling thickness reductions were ...Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced. To create cold weld between A1 and Ag, mating surfaces were specially prepared and various rolling thickness reductions were applied. The minimum critical thickness reduction to begin cold weld was specified as 70% which equals 0.1630 critical rolling shape factors. The bimetallic strips were treated by diffusion annealing at 400 ~C and various annealing time. The A1/Ag interface of strips was observed by scanning electron microscope to investigate the formation of hard and brittle probable phases. The effect of anneal time on diffusion distance and phase transformation was also analysed by EDS analysis and line scan. A diffusion region along the interface in the Ag side was observed and its width increased with prolonging annealing time. Some 8 phases were detected close to the interface after anneal treating for 3 h and 8 phase was thicker and more continuous by increasing annealing time. The microhardness measurement showed that in spite of formation of 8 phase due to diffusion annealing, the interface hardness was reduced.展开更多
The concept of steel sheet glass fiber reinforced polymer(GFRP)composite bar(SSGCB)was put forward.An optimization plan was proposed in the combined form of SSGCB.The composite principle,material selection,and SSGCB p...The concept of steel sheet glass fiber reinforced polymer(GFRP)composite bar(SSGCB)was put forward.An optimization plan was proposed in the combined form of SSGCB.The composite principle,material selection,and SSGCB preparation technology have been described in detail.Three-dimensional finite element analysis was adopted to perform the combination form optimization of different steel core structures and different steel core contents based on the mechanical properties.Mechanical tests such as uniaxial tensile,shear,and compressive tests were carried out on SSGCB.Parametric analysis was conducted to investigate the influence of steel content on the mechanical properties of SSGCB.The results revealed that the elastic modulus of SSGCB had improvements and increased with the rise of steel content.Shear strength was also increased with the addition of steel content.Furthermore,the yield state of SSGCB was similar to the steel bar,both of which indicated a multi-stage yield phenomenon.The compressive strength of SSGCB was lower than that of GFRP bars and increased with the increase of the steel core content.Stress-strain curves of SSGCB demonstrated that the nonlinear-stage characteristics of SSGCB-8 were much more obvious than other bars.展开更多
基金Supported by Innovation and Technology Fund (No.ITP/045/19AP)Commercial Research&Development (CRD) Funding Supported by Hong Kong Productivity Council (No.10008787)。
文摘We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.
基金Project(51375369)supported by the National Natural Science Foundation of ChinaProject(SYG201137)supported by the Science and Technology Development Program of Suzhou,China
文摘To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.
基金Project(2013AA031301)supported by National High-tech Research and Development Program of ChinaProject(51104016)supported by National Natural Science Foundation of ChinaProject(BM2014006)supported by Jiangsu Key Laboratory for Clad Materials,China
文摘The influences of rolling reduction and aluminum sheet initial thickness(AIT)on the thickness fluctuation of aluminum layer(TFA)of embedded aluminum?steel composite sheet produced by cold roll bonding were investigated,the formation mechanism of TFA was analyzed and method to improve the thickness uniformity of the aluminum layer was proposed.The results showed that when the reduction increased,TFA increased gradually.When the reduction was lower than40%,AIT had negligible effect on the TFA,while TFA increased with the decrease of AIT when the reduction was higher than40%.The non-uniformities of the steel surface deformation and the interfacial bonding extent caused by the work-hardened steel surface layer,were the main reasons for the formation of TFA.Adopting an appropriate surface treatment can help to decrease the hardening extent of the steel surface for improving the deformation uniformity during cold roll bonding process,which effectively improved the aluminum thickness uniformity of the embedded aluminum/steel composite sheets.
基金the Iranian Nanotechnology Development Committee for their financial supportthe University of Kashan for supporting this work (No. 891238/11)。
文摘In this paper,the stresses and buckling behaviors of a thick-walled mi-cro sandwich panel with a flexible foam core and carbon nanotube reinforced composite(CNTRC)face sheets are considered based on the high-order shear deformation theory(HSDT)and the modified couple stress theory(MCST).The governing equations of equi-librium are obtained based on the total potential energy principle.The effects of various parameters such as the aspect ratio,elastic foundation,temperature changes,and volume fraction of the canbon nanotubes(CNTs)on the critical buckling loads,normal stress,shear stress,and deflection of the thick-walled micro cylindrical sandwich panel consider-ing different distributions of CNTs are examined.The results are compared and validated with other studies,and showing an excellent compatibility.CNTs have become very use-ful and common candidates in sandwich structures,and they have been extensively used in many applications including nanotechnology,aerospace,and micro-structures.This paper also extends further applications of reinforced sandwich panels by providing the modified equations and formulae.
基金financial support of the National Natural Science Foundation of China (Nos.U20A20274,52071158,51701085,and U1664254)the Six Talents Peak Project of Jiangsu Province (2018-XCL-202)+1 种基金the Open Funds of SKLMMC of SJTU (MMC-KF18-16)the Jiangsu Provincial Key Laboratory of High-End Structural Materials (HSM1803,1902).
文摘To provide a new idea to reduce anisotropy for sheets in the thickness direction by microstructure modification and,mean-while,maintain or even enhance tensile performance,the in-situ ZrB2 particle/AA7085 composite sheets with thicknesses of 1,2,3,and 6 mm were investigated.The as-cast grain size was significantly refined by the heterogeneous nucleus of the ZrB2 particle.The microstructure results show that severe hot deformation converts as-cast disordered microstructure into a sequential microstructure by crushing the remanent phases and matrix into a fiber structure.After the solid solution and aging heat treatment,the composite sheets exhibit largely recrystallized grains compared with partially recrystallized grains in the matrix sheets,and weak or even free texture exists in the composite.The grain size in the composite sheets decreases with the increase in thickness reductions.For the thickness range of 1-3 mm,the composite sheets maintain a similar tensile per-formance as that in matrix sheets,while the strength and ductility in the 6-mm-thick composite sheet are improved.
基金This study is supported by Innovation and Technology Fund(ITP/045/19AP)Guangdong Academy of Science Fund(2020GDASYL-20200101001,2021GDASYL-20210102002)+2 种基金National Natural Science Foundation of China(51905111)Guangdong Basic and Applied Basic Research Project(2020B0301030006,2021A1515011730)International Science and Technology Cooperation Project of Guangdong Province(2021A0505030051).
文摘The feasibility of preparing Fe/Cu composite sheet was achieved by introducing submillimeter thickness Al sheet as an interlayer by rolling at room temperature.The shear test of the composite sheet supported that the metallurgical bonding strength between Fe/(Al)/Cu interface was stronger than that of Cu sheet at the initial state.With further 300 or 600℃ annealing treatments,the interlayer subsequently exhibited brittle shear fracture,and the shear strength significantly dropped under the shear test.Furthermore,the tensile test pointed out that the tensile fracture mechanism changed from fracture as a whole structure to interlayer-to-layer delamination mode after annealing treatment.The microstructure and X-ray diffraction observations proved that the formation of Cu–Al intermetallic compounds(IMCs)along the interlayer resulted in brittle fracture,rather than that of Fe–Al IMCs after annealing,especially under 600℃ annealing treatment.The investigation of the effect of the rolling process and annealing treatment on the mechanical properties of the Fe/(Al)/Cu composite sheet shall provide instruction for high-quality composite metallic sheet fabrication.
基金financed by the National Key Research and Development Program(No.2022YFB3705801)the National Natural Science Foundation of China(Nos.52031007 and 52171077).
文摘Electrochemical and localized corrosion behavior of a 4045/7072/3003 M/4045 Al alloy composite in 3.5 wt.%NaCl solution was investigated from cross-sectional and plane directions by electrochemical impedance spectroscopy,polarization curves,and high-resolution microscopic examination.Plane directions showed higher corrosion resistance than the cross-sectional surface,with almost all localized corrosion initiated from Si-containing inclusions.The cross-section showed a complex galvanic effect among the four layers,the galvanic coupling between 4045/7072 accelerated the dissolution of 7072 because 7072 served as the anode,however,the galvanic coupling between 3003 M/4045 protected 4045 from corrosion,indicating that 3003 M served as the anode.
文摘Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced. To create cold weld between A1 and Ag, mating surfaces were specially prepared and various rolling thickness reductions were applied. The minimum critical thickness reduction to begin cold weld was specified as 70% which equals 0.1630 critical rolling shape factors. The bimetallic strips were treated by diffusion annealing at 400 ~C and various annealing time. The A1/Ag interface of strips was observed by scanning electron microscope to investigate the formation of hard and brittle probable phases. The effect of anneal time on diffusion distance and phase transformation was also analysed by EDS analysis and line scan. A diffusion region along the interface in the Ag side was observed and its width increased with prolonging annealing time. Some 8 phases were detected close to the interface after anneal treating for 3 h and 8 phase was thicker and more continuous by increasing annealing time. The microhardness measurement showed that in spite of formation of 8 phase due to diffusion annealing, the interface hardness was reduced.
基金The authors may wish to express their sincere appreciation for the financial support provided by the National Key Research and Development Program of China(No.2017YFC0806008)Science and Technology Project of Department of Transportation of Hubei Province(No.2018-422-1-2)+3 种基金National Natural Science Foundation of China(Grant No.51178361)Major Project of Technological Innovation of Hubei Province(No.2018AAA031)China Scholarship Council(No.201906950026)the Fundamental Research Funds for the Central Universities(No.2019-YB-015)for this work.
文摘The concept of steel sheet glass fiber reinforced polymer(GFRP)composite bar(SSGCB)was put forward.An optimization plan was proposed in the combined form of SSGCB.The composite principle,material selection,and SSGCB preparation technology have been described in detail.Three-dimensional finite element analysis was adopted to perform the combination form optimization of different steel core structures and different steel core contents based on the mechanical properties.Mechanical tests such as uniaxial tensile,shear,and compressive tests were carried out on SSGCB.Parametric analysis was conducted to investigate the influence of steel content on the mechanical properties of SSGCB.The results revealed that the elastic modulus of SSGCB had improvements and increased with the rise of steel content.Shear strength was also increased with the addition of steel content.Furthermore,the yield state of SSGCB was similar to the steel bar,both of which indicated a multi-stage yield phenomenon.The compressive strength of SSGCB was lower than that of GFRP bars and increased with the increase of the steel core content.Stress-strain curves of SSGCB demonstrated that the nonlinear-stage characteristics of SSGCB-8 were much more obvious than other bars.