A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The resu...A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.展开更多
Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer ...Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.展开更多
Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The tech...Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.展开更多
The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods w...The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.展开更多
Cu/Al composite plates were fabricated using rolling and underwater explosive welding techniques,separately,to compare their interfacial microstructures and mechanical performance.Interface morphology,grain orientatio...Cu/Al composite plates were fabricated using rolling and underwater explosive welding techniques,separately,to compare their interfacial microstructures and mechanical performance.Interface morphology,grain orientation,grain boundary characteristics,and phase distribution were analyzed through optical microscope,scanning electron microscope,and electron backscattered diffractometer.Mechanical properties were assessed using tensile shear tests,90°bending tests,and hardness measurements.Vickers hardness and nanoindentation test results further provided information on the hardness distributions.Results indicate that the diffusion layer in rolled Cu/Al composites is relatively fragile,while that produced by underwater explosive welding features a diffusion layer of approximately 18μm in thickness,which is metallurgically bonded through atomic diffusion.The tensile shear strength of these composites ranges from 64.45 MPa to 70.84 MPa,and in the 90°three-point bending test,the underwater-explosive-welded samples exhibit superior flexural performance.This study elucidates the effects of different manufacturing methods on the interfacial properties and mechanical performance of Cu/Al composites,offering essential insights for the selection of manufacturing methods and applications.展开更多
AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the...AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the interface was investigated.Moreover,the interface bonding mechanisms of the AZ31/Al/Ta composites during the VHCB process were explored.The results demonstrate that as the VHCB temperature increases,the phase composition of the interface between Mg and Al changes from the Mg-Al brittle intermetallic compounds(Al_(12)Mg_(17)and Al_(3)Mg_(2))to the Al-Mg solid solution.Meanwhile,the width of the Al/Ta interface diffusion layer at 450℃increases compared to that at 400℃.The shear strengths are 24 and 46 MPa at 400 and 450℃,respectively.The interfacial bonding mechanism of AZ31/Al/Ta composites involves the coexistence of diffusion and mechanical meshing.Avoiding the formation of brittle phases at the interface can significantly improve interfacial bonding strength.展开更多
Carbon fibers （CF） were surface treated with air-oxidation and rare earths （RE）, respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroeth...Carbon fibers （CF） were surface treated with air-oxidation and rare earths （RE）, respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites was invest/gated. Experimental results revealed that RE was superior to air ox/dation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE （CF/PTFE） composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.展开更多
The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive mod...The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures （plain, twill 1/3 and satin 8/5） of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy （SEM）. The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions： the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism of fabric composites.展开更多
Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites fi...Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites filled with carbon fibers treated with different treatment methods. Tribological properties of the PTFE composites, sliding against GCr15 steel under water-lubricated condition, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the composites were examined using scanning electron microscopy. Experimental results reveal that RE treatment is superior to air oxidation in promoting tribological properties of CF reinforced PTFE （CF/PTFE） composite. The friction and wear properties of PTFE composite filled with RE treated CF are the best of the PTFE composites. RE treatment is more effective than air oxidation to improve the tribological properties of CF/PTFE composite owing to the effective improvement of interfacial adhesion between carbon fibers and PTFE matrix.展开更多
The sealing rings are one of the most important components as the sealing devices in the wet clutch unit of a heavy vehicle. The sealing ring, made from PTFE composites, was subjected to serious wear on the sealing su...The sealing rings are one of the most important components as the sealing devices in the wet clutch unit of a heavy vehicle. The sealing ring, made from PTFE composites, was subjected to serious wear on the sealing surface, but the mating metal surface only had slight abrasion. A specialized test rig was designed for wear research and failure analysis of the sealing ring. The composition analyses of the ring material, working conditions and wear surface characteristics by visual inspection and tribological properties as well as microscopic analysis with scanning electron microscope was performed to determine the wear mechanism and failure causes. Results revealed that the wear of PTFE composites was characterized by abrasion and adhesion after a certain duration testing, and the wear mechanism changed to thermal fatigue and abrasive wear in the stage of intense wear. The thermal deformation and fatigue were primarily responsible for the rapid wear of the PTFE composites for the sealing rings.展开更多
The effect of rare earths （RE） surface treatment of carbon fibers （CF） on tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites under oil-lubricated condition was investigated. Exper...The effect of rare earths （RE） surface treatment of carbon fibers （CF） on tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites under oil-lubricated condition was investigated. Experimental results revealed that RE treated CF reinforced PTFE （CF/PTFE） composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air-oxidated composites. X-ray photoelectron spectroscopy （XPS） study of carbon fiber surface showed that, after RE treatment, oxygen concentration increased obviously, and the amount of oxygen-containing groups on CF surfaces were largely increased. The increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with VITE matrix, and large scale rubbing-off of PTFE be prevented, therefore, tribological properties of the composite was improved.展开更多
Edge defects significantly impact the forming quality of Mg/Al composite plates during the rolling process.This study aims to develop an effective rolling technique to suppress these defects.First,an enhanced Lemaitre...Edge defects significantly impact the forming quality of Mg/Al composite plates during the rolling process.This study aims to develop an effective rolling technique to suppress these defects.First,an enhanced Lemaitre damage model with a generalized stress state damage prediction mechanism was used to evaluate the key mechanical factors contributing to defect formation.Based on this evaluation,an embedded composite rolling technique was proposed.Subsequently,comparative validation was conducted at 350℃ with a 50% reduction ratio.Results showed that the plates rolled using the embedded composite rolling technique had smooth surfaces and edges,with no macroscopic cracks observed.Numerical simulation indicated that,compared to conventional processes,the proposed technique reduced the maximum edge stress triaxiality of the plates from-0.02 to-1.56,significantly enhancing the triaxial compressive stress effect at the edges,which suppressed void nucleation and growth,leading to a 96%reduction in damage values.Mechanical property evaluations demonstrated that,compared to the conventional rolling process,the proposed technique improved edge bonding strength and tensile strength by approximately 67.7%and 118%,respectively.Further microstructural characterization revealed that the proposed technique,influenced by the restriction of deformation along the transverse direction(TD),weakened the plastic flow in the TD and enhanced plastic flow along the rolling direction(RD),resulting in higher grain boundary density and stronger basal texture.This,in turn,improved the toughness and transverse homogeneity of the plates.In summary,the embedded composite rolling technique provides crucial technical guidance for the preparation of Mg-based composite plates.展开更多
1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain bounda...1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].展开更多
The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3....The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.展开更多
In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The...In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.展开更多
The aluminum(Al)/steel transition joints used in ships are processed from composite plates,and their mechanical properties have a significant impact on the safety of ships.In this paper,the Al/steel composite plate wa...The aluminum(Al)/steel transition joints used in ships are processed from composite plates,and their mechanical properties have a significant impact on the safety of ships.In this paper,the Al/steel composite plate was prepared using rolling,with 5083 aluminum plate as the cladding plate,Q235 steel plate as the substrate,and TA1 titanium(Ti)plate and DT4 pure iron(Fe)plate as the intermediate layers.The heterothermic billet was prepared through induction heating by the magnetic effects of the steel plate and the pure Fe plate,and then the Al/steel composite plate was obtained by rolling.The impacts of post-rolling cooling process on the microstructure and properties of the Al/Ti/pure Fe/steel composite plate were studied.The results manifested that the pure Fe/steel interface had a good composite effect.With the increase in the cooling rate,the bonding strength of the Al/Ti interface was raised,and that of the Ti/Fe interface was increased first and then decreased.When the oil cooling process was adopted,the Al/Ti/pure Fe/steel composite plate exhibited the highest comprehensive performance.The shear strength of the Al/Ti interface and the Ti/Fe interface was 102 MPa and 186 MPa,respectively.The plastic fracture was determined as the mode of interface fracture.展开更多
Improving the thermal conductivity(TC)of diamond–metal composites has always been a significant challenge in the field of thermal management.In this paper,diamond/Al composites are systematically studied,and the infl...Improving the thermal conductivity(TC)of diamond–metal composites has always been a significant challenge in the field of thermal management.In this paper,diamond/Al composites are systematically studied,and the influence of the holding time(10–120 min)on interface structure and TC is discussed.The results of this research show that longterm thermal diffusion sintering can achieve dense interfacial bonding in diamond/Al composites,enhancing their TC.Diamond/Al composites with 50 vol%of 900μm diamond attain the highest TC value of 888.73 W·m^(-1)·K^(-1)under sintering conditions of 650?C,50 MPa,and 120 min—nearly 92%of the theoretical value predicted by the Maxwell model.This study establishes that high TC can be achieved through long-term thermal diffusion alone,without the need for complex diamond surface coating or substrate alloying.展开更多
1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was in...1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was investigated by microstructural characterization,mechanical property tests and in-situ fracture morphology observations.The results show that microstructural differences between the constituent layers are present in the Al/Al LMCs after various numbers of ARB cycles.Compared with rolled 2560-layered Al/Al LMCs with 37.5%and 50.0%rolling reductions,those with 62.5%rolling reductions allow for more effective improvements in the mechanical properties after annealing treatment due to their relatively high mechanical incompatibility across the interface.During tensile deformation,with the increased magnitude of incompatibility in the 2560-layered Al/Al LMC with a heterogeneous lamellar structure,the densities of the geometrically necessary dislocations(GNDs)increase to accommodate the relatively large strain gradient,resulting in considerable back stress strengthening and improved mechanical properties.展开更多
Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investiga...Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.展开更多
Al/steel bimetallic composites were prepared by compound casting,and the effects of the rotating magnetic field on the interfacial microstructure and shear property of bimetallic composite was investigated.The applica...Al/steel bimetallic composites were prepared by compound casting,and the effects of the rotating magnetic field on the interfacial microstructure and shear property of bimetallic composite was investigated.The application of rotating magnetic field refined the grain structure of the Al alloy matrix,changed the eutectic Si morphology from coarse lath to needle-like.The rotating magnetic field improved the temperature field and solute distribution of the Al alloy melt,enriched a layer of Si at the interface,and suppressed the growth of intermetallic compounds,the thickness of the interface layer decreased from 44.9μm to 22.8μm.The interfacial intermetallic compounds consisted ofη-Al_(5)Fe_(2),θ-Al_(13)Fe_(4),τ6-Al_(4.5)FeSi,τ_(5)-Al_(8)Fe_(2)Si andτ_(3)-Al_(2)FeSi,and the addition of the rotating magnetic field did not change phase composition.The rotating magnetic field improved the stress distribution within the interfacial intermetallic compounds,the presence of high-angle grain boundaries retarded crack extension,and the shear strength was enhanced from 31.27±3 MPa to 52.70±4 MPa.This work provides a feasible method for preparing Al/steel bimetallic composite with good bonding property.展开更多
基金supported by Guangdong Major Project of Basic and Applied Basic Research, China (No. 2020B0301030006)Fundamental Research Funds for the Central Universities, China (No. SWU-XDJH202313)+1 种基金Chongqing Postdoctoral Science Foundation Funded Project, China (No. 2112012728014435)the Chongqing Postgraduate Research and Innovation Project, China (No. CYS23197)。
文摘A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.
基金Opening Foundation of Key Laboratory of Explosive Energy Utilization and Control,Anhui Province(BP20240104)Graduate Innovation Program of China University of Mining and Technology(2024WLJCRCZL049)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_2701)。
文摘Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.
文摘Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.
基金supported by the general project of the National Natural Science Foundation of China(No.52071042)Chongqing Natural Science Foundation Project,China(Nos.CSTB2023NSCQ-MSX0079,cstc2021ycjh-bgzxm0148)Graduate Student Innovation Program of Chongqing University of Technology,China(No.gzlcx20232008).
文摘The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.
基金Anhui Province Key Research and Development Plan(2022a05020021)China Coal Science and Industry Group Chongqing Research Institute Independent Research and Development Project(2023YBXM58)。
文摘Cu/Al composite plates were fabricated using rolling and underwater explosive welding techniques,separately,to compare their interfacial microstructures and mechanical performance.Interface morphology,grain orientation,grain boundary characteristics,and phase distribution were analyzed through optical microscope,scanning electron microscope,and electron backscattered diffractometer.Mechanical properties were assessed using tensile shear tests,90°bending tests,and hardness measurements.Vickers hardness and nanoindentation test results further provided information on the hardness distributions.Results indicate that the diffusion layer in rolled Cu/Al composites is relatively fragile,while that produced by underwater explosive welding features a diffusion layer of approximately 18μm in thickness,which is metallurgically bonded through atomic diffusion.The tensile shear strength of these composites ranges from 64.45 MPa to 70.84 MPa,and in the 90°three-point bending test,the underwater-explosive-welded samples exhibit superior flexural performance.This study elucidates the effects of different manufacturing methods on the interfacial properties and mechanical performance of Cu/Al composites,offering essential insights for the selection of manufacturing methods and applications.
基金National Natural Science Foundation of China(52275308,52301146)Fundamental Research Funds for the Central Universities(2023JG007)Supported by Shi Changxu Innovation Center for Advanced Materials(SCXKFJJ202207)。
文摘AZ31/Al/Ta composites were prepared using the vacuum hot compression bonding(VHCB)method.The effect of hot compressing temperature on the interface microstructure evolution,phase constitution,and shear strength at the interface was investigated.Moreover,the interface bonding mechanisms of the AZ31/Al/Ta composites during the VHCB process were explored.The results demonstrate that as the VHCB temperature increases,the phase composition of the interface between Mg and Al changes from the Mg-Al brittle intermetallic compounds(Al_(12)Mg_(17)and Al_(3)Mg_(2))to the Al-Mg solid solution.Meanwhile,the width of the Al/Ta interface diffusion layer at 450℃increases compared to that at 400℃.The shear strengths are 24 and 46 MPa at 400 and 450℃,respectively.The interfacial bonding mechanism of AZ31/Al/Ta composites involves the coexistence of diffusion and mechanical meshing.Avoiding the formation of brittle phases at the interface can significantly improve interfacial bonding strength.
基金Project supported by the National Natural Science Foundation of China (50275093)
文摘Carbon fibers （CF） were surface treated with air-oxidation and rare earths （RE）, respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites was invest/gated. Experimental results revealed that RE was superior to air ox/dation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE （CF/PTFE） composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.
基金supported by National Defense Foundation of China
文摘The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures （plain, twill 1/3 and satin 8/5） of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy （SEM）. The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions： the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism of fabric composites.
基金Project supported bythe National Natural Science Foundation of China (50275093)
文摘Carbon fibers （CFs） were surface treated with air-oxidation, rare earths （RE） after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites filled with carbon fibers treated with different treatment methods. Tribological properties of the PTFE composites, sliding against GCr15 steel under water-lubricated condition, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the composites were examined using scanning electron microscopy. Experimental results reveal that RE treatment is superior to air oxidation in promoting tribological properties of CF reinforced PTFE （CF/PTFE） composite. The friction and wear properties of PTFE composite filled with RE treated CF are the best of the PTFE composites. RE treatment is more effective than air oxidation to improve the tribological properties of CF/PTFE composite owing to the effective improvement of interfacial adhesion between carbon fibers and PTFE matrix.
基金Funded by the National Natural Science Foundation of China(Nos.51005104, 51105288)Jiangsu Province Basic Research Program(Natural Science Foundation) (No.BK2011477)+1 种基金China Postdoctoral Science Foundation(No.20110491355)Young Excellent Teachers Training Project of Jiangsu University
文摘The sealing rings are one of the most important components as the sealing devices in the wet clutch unit of a heavy vehicle. The sealing ring, made from PTFE composites, was subjected to serious wear on the sealing surface, but the mating metal surface only had slight abrasion. A specialized test rig was designed for wear research and failure analysis of the sealing ring. The composition analyses of the ring material, working conditions and wear surface characteristics by visual inspection and tribological properties as well as microscopic analysis with scanning electron microscope was performed to determine the wear mechanism and failure causes. Results revealed that the wear of PTFE composites was characterized by abrasion and adhesion after a certain duration testing, and the wear mechanism changed to thermal fatigue and abrasive wear in the stage of intense wear. The thermal deformation and fatigue were primarily responsible for the rapid wear of the PTFE composites for the sealing rings.
基金the National Natural Science Foundation of China (50275093)
文摘The effect of rare earths （RE） surface treatment of carbon fibers （CF） on tribological properties of CF reinforced polytetrafluoroethylene （PTFE） composites under oil-lubricated condition was investigated. Experimental results revealed that RE treated CF reinforced PTFE （CF/PTFE） composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air-oxidated composites. X-ray photoelectron spectroscopy （XPS） study of carbon fiber surface showed that, after RE treatment, oxygen concentration increased obviously, and the amount of oxygen-containing groups on CF surfaces were largely increased. The increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with VITE matrix, and large scale rubbing-off of PTFE be prevented, therefore, tribological properties of the composite was improved.
基金supported by National Key Research and Development Program(2018YFA0707300)Major Program of National Natural Science Foundation of China(U22A20188).
文摘Edge defects significantly impact the forming quality of Mg/Al composite plates during the rolling process.This study aims to develop an effective rolling technique to suppress these defects.First,an enhanced Lemaitre damage model with a generalized stress state damage prediction mechanism was used to evaluate the key mechanical factors contributing to defect formation.Based on this evaluation,an embedded composite rolling technique was proposed.Subsequently,comparative validation was conducted at 350℃ with a 50% reduction ratio.Results showed that the plates rolled using the embedded composite rolling technique had smooth surfaces and edges,with no macroscopic cracks observed.Numerical simulation indicated that,compared to conventional processes,the proposed technique reduced the maximum edge stress triaxiality of the plates from-0.02 to-1.56,significantly enhancing the triaxial compressive stress effect at the edges,which suppressed void nucleation and growth,leading to a 96%reduction in damage values.Mechanical property evaluations demonstrated that,compared to the conventional rolling process,the proposed technique improved edge bonding strength and tensile strength by approximately 67.7%and 118%,respectively.Further microstructural characterization revealed that the proposed technique,influenced by the restriction of deformation along the transverse direction(TD),weakened the plastic flow in the TD and enhanced plastic flow along the rolling direction(RD),resulting in higher grain boundary density and stronger basal texture.This,in turn,improved the toughness and transverse homogeneity of the plates.In summary,the embedded composite rolling technique provides crucial technical guidance for the preparation of Mg-based composite plates.
基金support by the National Natural Science Foundation of China(Grant Nos.U23A20546 and 52271010)the Chinese National Natural Science Fund for Distinguished Young Scholars(Grant No.52025015)the Natural Science Foundation of Tianjin City(No.21JCZDJC00510).
文摘1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)Key Project of Chongqing Technology Innovation and Application Development Special Project(CSTB2023TIADKPX0016,CSTB2022TIAD-KPX0027)+1 种基金National Natural Science Foundation of China(51971183)the Science and Technology Program of Xinjiang Production and Construction Corps(2024AB056).
文摘The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+4 种基金the Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202301)the Guangdong Academy of Science Fund(2020GDASYL-20200101001,2023GDASQNRC-0210,2023GDASQNRC-0321)the Guangdong Science and Technology plan project(2023A0505030002)the GINM’Special Project of Science and Technology Development(2023GINMZX-202301020108)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.
基金Supported by Science Research Project of Hebei Education Department(Grant No.BJK2024138)Hebei Provincial Natural Science Foundation(Grant No.E2023203129)National Natural Science Foundation of China(Grant Nos.52004242,52075472).
文摘The aluminum(Al)/steel transition joints used in ships are processed from composite plates,and their mechanical properties have a significant impact on the safety of ships.In this paper,the Al/steel composite plate was prepared using rolling,with 5083 aluminum plate as the cladding plate,Q235 steel plate as the substrate,and TA1 titanium(Ti)plate and DT4 pure iron(Fe)plate as the intermediate layers.The heterothermic billet was prepared through induction heating by the magnetic effects of the steel plate and the pure Fe plate,and then the Al/steel composite plate was obtained by rolling.The impacts of post-rolling cooling process on the microstructure and properties of the Al/Ti/pure Fe/steel composite plate were studied.The results manifested that the pure Fe/steel interface had a good composite effect.With the increase in the cooling rate,the bonding strength of the Al/Ti interface was raised,and that of the Ti/Fe interface was increased first and then decreased.When the oil cooling process was adopted,the Al/Ti/pure Fe/steel composite plate exhibited the highest comprehensive performance.The shear strength of the Al/Ti interface and the Ti/Fe interface was 102 MPa and 186 MPa,respectively.The plastic fracture was determined as the mode of interface fracture.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12274372 and 12274373)the Major Science and Technology Projects of Henan Province(Grant No.231100230300)。
文摘Improving the thermal conductivity(TC)of diamond–metal composites has always been a significant challenge in the field of thermal management.In this paper,diamond/Al composites are systematically studied,and the influence of the holding time(10–120 min)on interface structure and TC is discussed.The results of this research show that longterm thermal diffusion sintering can achieve dense interfacial bonding in diamond/Al composites,enhancing their TC.Diamond/Al composites with 50 vol%of 900μm diamond attain the highest TC value of 888.73 W·m^(-1)·K^(-1)under sintering conditions of 650?C,50 MPa,and 120 min—nearly 92%of the theoretical value predicted by the Maxwell model.This study establishes that high TC can be achieved through long-term thermal diffusion alone,without the need for complex diamond surface coating or substrate alloying.
基金financial support from the Special Fund for Special Posts of Guizhou University,China(No.[2022]06)the Guizhou Provincial Basic Research Program(Natural Science),China(No.ZK[2023]78)+1 种基金the National Natural Science Foundation of China(No.52365020)the Open Fund Project of Key Laboratory of Advanced Manufacturing Technology,China(No.GZUAMT2022KF[04]).
文摘1060/7050 Al/Al laminated metal composites(LMCs)with heterogeneous lamellar structures were prepared by accumulative roll bonding(ARB),cold rolling and subsequent annealing treatment.The strengthening mechanism was investigated by microstructural characterization,mechanical property tests and in-situ fracture morphology observations.The results show that microstructural differences between the constituent layers are present in the Al/Al LMCs after various numbers of ARB cycles.Compared with rolled 2560-layered Al/Al LMCs with 37.5%and 50.0%rolling reductions,those with 62.5%rolling reductions allow for more effective improvements in the mechanical properties after annealing treatment due to their relatively high mechanical incompatibility across the interface.During tensile deformation,with the increased magnitude of incompatibility in the 2560-layered Al/Al LMC with a heterogeneous lamellar structure,the densities of the geometrically necessary dislocations(GNDs)increase to accommodate the relatively large strain gradient,resulting in considerable back stress strengthening and improved mechanical properties.
基金the financial support from the National Natural Science Foundation of China(Nos.51875317,52222510)Key Research and Development Program of Shandong Province,China(No.2021ZLGX01)。
文摘Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.
基金supported by the Natural Science Foundation of Shanxi Province(202103021224193).
文摘Al/steel bimetallic composites were prepared by compound casting,and the effects of the rotating magnetic field on the interfacial microstructure and shear property of bimetallic composite was investigated.The application of rotating magnetic field refined the grain structure of the Al alloy matrix,changed the eutectic Si morphology from coarse lath to needle-like.The rotating magnetic field improved the temperature field and solute distribution of the Al alloy melt,enriched a layer of Si at the interface,and suppressed the growth of intermetallic compounds,the thickness of the interface layer decreased from 44.9μm to 22.8μm.The interfacial intermetallic compounds consisted ofη-Al_(5)Fe_(2),θ-Al_(13)Fe_(4),τ6-Al_(4.5)FeSi,τ_(5)-Al_(8)Fe_(2)Si andτ_(3)-Al_(2)FeSi,and the addition of the rotating magnetic field did not change phase composition.The rotating magnetic field improved the stress distribution within the interfacial intermetallic compounds,the presence of high-angle grain boundaries retarded crack extension,and the shear strength was enhanced from 31.27±3 MPa to 52.70±4 MPa.This work provides a feasible method for preparing Al/steel bimetallic composite with good bonding property.
