Improving interfacial bonding and alloying design are effective strategies for enhancing mechanical properties of particle-reinforced steel matrix composites(SMCs).This study prepared SMCs with uniformly distributed T...Improving interfacial bonding and alloying design are effective strategies for enhancing mechanical properties of particle-reinforced steel matrix composites(SMCs).This study prepared SMCs with uniformly distributed TiC_(P)in matrix using master alloying method.The TiC(002)/Fe(011)interface model was established based on the orientation relationship of(011)_(Fe)//(002)_(TiC),and[100]_(Fe)//[100]_(TiC).The effects of single and co-doping of alloying elements(Mn,Cr,Mo,Ni,Cu and Si)on the interface bonding behavior of TiC/Fe in composites were investigated in conjunction with first principles.The results demonstrate that the interface between TiC and matrix is continuous and stable.Compared to the undoped TiC/Fe interface,single-doping Mn,Cr,and Mo can improve the stability of TiC/Fe interface and enhance tensile strength.Conversely,single-doping with Ni,Cu,and Si reduced the interface stability and marginally reduces tensile strength.Relative to the undoped and singly Ni-doped TiC/Fe interfaces,the co-doping Ni-Mo boosts binding energy and separation work at the TiC/Fe interface,which is conducive to the interface bonding between TiC_(P)and matrix,and thus improves the mechanical properties of composites.Thus,in the alloying design of TiC particle reinforced low-alloy SMCs,incorporating Mn,Cr,Mo,and Ni into matrix can enhance the overall mechanical properties of composites.展开更多
The segregation behavior of alloying elements X（ X = Zr,V,Cr,Mn,Mo,W,Nb,Y） on the ferrite（ 100） /TiC（ 100） interface has been investigated using first principles method,and the work of separation and interface e...The segregation behavior of alloying elements X（ X = Zr,V,Cr,Mn,Mo,W,Nb,Y） on the ferrite（ 100） /TiC（ 100） interface has been investigated using first principles method,and the work of separation and interface energy of ferrite / TiC interfaces alloyed by these elements were also analyzed. The results indicated that all these alloying additives except Y were thermodynamically favorable because of the negative segregation energy,showing that they have the tendency to segregate to the ferrite / TiC interface. When the Fe atom in the ferrite /TiC interface is replaced by Y,Zr,or Nb,the adhesive strength of the interface will be weakened due to the lower separation work,larger interfacial energy,and weaker electron effects. However,the introduction of Cr,Mo,W,Mn and V will improve the stability of the ferrite / TiC interface through strong interaction between these elements and C,and Cr-doped interface is the most stable structure. Therefore,the Cr,Mo,W,Mn and V in ferrite side of the interface can effectively promote ferrite heterogeneous nucleation on TiC surface to form fine ferrite grain.展开更多
Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensi...Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.展开更多
The 3D morphologies and growth mechanisms of proeutectic FeAl_(3) at the Al/Fe interface under different cooling rates were studied by synchrotron X-ray tomography.With increasing cooling rate,FeAl_(3) crystals develo...The 3D morphologies and growth mechanisms of proeutectic FeAl_(3) at the Al/Fe interface under different cooling rates were studied by synchrotron X-ray tomography.With increasing cooling rate,FeAl_(3) crystals developed from faceted polygonal prism,plates with flat surface,thin ribbon-like with periodic undulating surface to non-faceted rods with radial dendrites in cross section,indicating a gradual interface growth mode transition from two-dimensional layer growth to continuous growth.At a higher cooling rate,twinning mechanism plays a leading role in the formation and growth of FeAl_(3).A link between the morphologies,twinning and crystallographic structure was established based on quantitative analyses on the 3D structures.展开更多
Based on YU’s solids and molecules emperical electron theory(EET), interface valence electron structure of TiC-Fe3Al composites was set up, and the valence electron density of different atomic states TiC and Fe3Al co...Based on YU’s solids and molecules emperical electron theory(EET), interface valence electron structure of TiC-Fe3Al composites was set up, and the valence electron density of different atomic states TiC and Fe3Al composites in various planes was determined. The results indicate that the electron density of (1 00)Fe3Al is consistent with that of (110)TiC in the first-class a pproximation, the absolute value of minimum electron density difference along the interface is 0.007 37 nm?2, and the relative value is 0.759%. (1 10)TiC //(100)Fe3Al preferred orientation is believed to benefit the formation of the cuboidal shape TiC. In the other hand, it shows that the particle growth is accompanied by the transport of electron, the deviation continuity of electron density intrinsically hinders the grain growth. The electron density of (100)TiC is not consistent with Fe3Al arbitrary crystallographic plane, thus it well explains that the increased titanium and carbon contents do not increase the size of large particles. The crystallographic orientation of (1 10)TiC //(100)Fe3Al will improve the mechanical properties. Therefore interface electron theory is an effective theoretical implement for designing excellent property of composites.展开更多
The morphology. orientation relationship and stability of TiC/γ interface in Fe-Cr-Ni base composite synthesized with a liquid state in-situ process have been studied. The TiC/γ interface in as-cast sample is of coh...The morphology. orientation relationship and stability of TiC/γ interface in Fe-Cr-Ni base composite synthesized with a liquid state in-situ process have been studied. The TiC/γ interface in as-cast sample is of coherent feature. Its orientation relationship is (020)γ／／(220)TiC, [001]γ||[001]TiC. During the aging at 1473 K, the TiC/γ interface may dissolve in matrix and lamellar M23C6 compound may precipitate from γ-matrix.展开更多
The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy...The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.展开更多
The effects of vanadium(V)on the microstructures and mechanical properties of the TiC cermet fusion welding interface were studied by adjusting the content of V in the self-developed flux-cored wires using metal inert...The effects of vanadium(V)on the microstructures and mechanical properties of the TiC cermet fusion welding interface were studied by adjusting the content of V in the self-developed flux-cored wires using metal inert gas arc(MIG)welding for surfacing on the TiC cermet.The results show that the increase in V content promotes the element diffusion between TiC cermet and weld metal.There are no de-fects observed in the interface,and the diffusion of elements refers to excellent metallurgical bonding.The shear strength of the fusion zone initially decreases and then increases with the increase in V content.The maximum shear strength of the TiC cermet/weld interface,reaching 552 MPa,occurred when the V content reached 0.65%.Meanwhile,the average hardness in the transition zone reached 488.2 HV0.2.展开更多
A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes p...A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.展开更多
Electronic structure, stability and bonding strength of a-Fe/WC interfaces between Ce-doped and undoped WC cermet coating were investigated by first-principles methodology based on densityfunctional theory(DFT). Based...Electronic structure, stability and bonding strength of a-Fe/WC interfaces between Ce-doped and undoped WC cermet coating were investigated by first-principles methodology based on densityfunctional theory(DFT). Based on the minimum mismatched lattices, the relatively stable interface that forms between WC(100) and bcc a-Fe(100) was employed to predict the atomic structure, bonding,and ideal work of adhesion. There are three possible positions which were defined as OT, MT, HCP, taking into account both C-and W-terminations. The sequence of structural stability tested in this paper was:MT > OT > HCP. After full relaxation, the results show that only the first and second layers of the interface have significant influence on the electronic structure between Fe and WC. The interaction of Ce elements at the interface is achieved by comparing the interface structure and electronic structure of the doped and undoped interfaces. Ce doped interface possesses a shorter interface distance(d0 = 0.09776 nm)and a larger interface energy(Wad = 8.98 J/m2) than undoped interface(Wad = 8.76 J/m2,d0= 0.10134 nm).Charge density distribution and difference, and density of states were utilized to characterize the electronic properties and determine the interfacial bonding.The results demonstrate that strong covalent bonding existed in the undoped interface, while a mixed covalent/ionic bonding was formed at the Ce-doped interface.展开更多
Phase structure characteristics near the interface of Fe3Al/Q235 diffusion bonding are investigated by means of X raydiffraction (XRD), transmission electronic microscope (TEM) and electron diffraction, etc. The test ...Phase structure characteristics near the interface of Fe3Al/Q235 diffusion bonding are investigated by means of X raydiffraction (XRD), transmission electronic microscope (TEM) and electron diffraction, etc. The test results indicatedthat obviously a diffusion transition zone forms near the interface of Fe3Al/Q235 under the condition of heatingtemperature 1050~1100℃, holding time 60 min and pressure 9.8 MPa, which indicated that the diffusion interfaceof Fe3Al/Q235 was combined well. The diffusion transition zone consisted of Fe3Al and a-Fe(Al) solid solution.Microhardness near the diffusion transition zone was HM 480~540. There was not brittle phase of high hardness inthe interface transition zone. This is favorable to enhance toughness of Fe3Al/Q235 diffusion joint.展开更多
In-situ formed TiC particles were introduced into α-Fe matrix as corrosion-resistant phases to enhance corrosion resistance against aluminum melt of the alloy.The effects of TiC content on the microstructure and corr...In-situ formed TiC particles were introduced into α-Fe matrix as corrosion-resistant phases to enhance corrosion resistance against aluminum melt of the alloy.The effects of TiC content on the microstructure and corrosion behavior of Fe-TiC alloys were examined both experimentally and theoretically.The results indicate that eutectic Fe-6TiC alloy offers superior corrosion resistance to liquid aluminum,which is 7.5 times greater than that of H13 die steel.The long rod-shaped and granular eutectic TiC particles provide superior resistance to aluminum melt diffusion compared to blocky primary TiC.Moreover,these eutectic TiC particles improve the bonding strength of the intermetallic compound layer,inhibiting cracking,peeling,and dissolution of the corrosion layer.A novel theoretical numerical model is established to quantitatively account for the corrosion behavior of the ferrous alloys in aluminum melt,and the diffusion inhibition factor λ and dissolution inhibition factorεare introduced in this work to quantitatively estimate the corrosion performance.Theoretical analysis demonstrates that Fe-6TiC eutectic alloy containing numerous long rod-shaped and granular eutectic TiC exhibits the best corrosion resistance.展开更多
The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the i...The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the interface are greatly increased after 820℃, 2 h water quenching and 450℃, 6 h aging. This result probablycomes from much more U2Ti and U6Ni precipitates along the interface.展开更多
The preparation of TiC coating on Ti alloy surface to improve the wear resistance has attracted attention from researchers in aerospace field.The service life of TiC coating is related to the interfacial adhesion prop...The preparation of TiC coating on Ti alloy surface to improve the wear resistance has attracted attention from researchers in aerospace field.The service life of TiC coating is related to the interfacial adhesion properties between TiC coating and Ti alloy substrate.However,it is difficult to explain its interfacial adhesion mechanism by experimental methods.Based on the termination of atoms on the TiC surface,two TiC/Ti interface models named as the C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(11)/Ti(0001) interface were constructed by first-principles.The interfacial electronic characteristic of C-Ti bond is a mixture of polar covalent and metal bonds,and that of Ti-Ti bond is the metal bond.The tensile strains of both C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface in the fracture stage are ranged from 12% to 14%.Their maximum tensile stresses are 16.201 GPa and 15.590GPa,respectively.The sliding potential energy surface maximum of C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface are 5.387 J/m^(2) and 0.271 J/m^(2),respectively.And the sliding potential barriers on the minimum energy path are 2.094 J/m2and 0.136 J/m^(2) with an ideal shear strength of 20.32 GPa and 1.61 GPa,respectively.In summary,the interfacial adhesion property of C-terminated-TiC(111)/Ti(0001) interface is better than that of Ti-terminated-TiC(111)/Ti(0001) interface.展开更多
The electronic structure of fcc Fe/Cu{111}interface has been studied by angle-resolved photoemission with synchrotron radiation.The existence of the interface state and absence of intermixture between Fe and Cu atoms ...The electronic structure of fcc Fe/Cu{111}interface has been studied by angle-resolved photoemission with synchrotron radiation.The existence of the interface state and absence of intermixture between Fe and Cu atoms in the Fe/Cu{111}interface show that the Fe/Cu{111}system has an abrupt and ordered interface.展开更多
Recently,metal-graphene nanocomposite system has aroused much interest due to its radiation tolerance behavior.However,the related atomic mechanism for the metal-graphene interface is still unknown.Further,stainless s...Recently,metal-graphene nanocomposite system has aroused much interest due to its radiation tolerance behavior.However,the related atomic mechanism for the metal-graphene interface is still unknown.Further,stainless steels with Fe as main matrix are widely used in nuclear systems.Therefore,in this study,the atomic behaviors of point defects and helium(He) atoms at the Fe(110)-graphene interface are investigated systematically by first principles calculations.The results indicate that graphene interacts strongly with the Fe(110) substrate.In comparison with those of the original graphene and bulk Fe,the formation energy values of C vacancies and Fe point defects decrease significantly for Fe(110)-graphene.However,as He atoms have a high migration barrier and large binding energy at the interface,they are trapped at the interface once they enter into it.These theoretical results suggest that the Fe(110)-graphene interface acts as a strong sink that traps defects,suggesting the potential usage of steel-graphene with multiply interface structures for tolerating the radiation damage.展开更多
Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation ...Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).展开更多
Fe3Al and Crl8-Ni8 steel were bonded in vacuum and an interface was formed between Fe3Al and Crl8-Ni8 steel. Stress distribution at the diffusion-bonded interface was researched by numerical simulation and finite elem...Fe3Al and Crl8-Ni8 steel were bonded in vacuum and an interface was formed between Fe3Al and Crl8-Ni8 steel. Stress distribution at the diffusion-bonded interface was researched by numerical simulation and finite element method （FEM）. The results indicated that the peak stress appeared at the interface near Cr18-Ni8 steel side. This is the key factor to induce crack at this position. With the enhancement of heating temperature, the peak stress at the bonded interface increases. When the temperature is 1 100 22, the peak stress is up to 65.9 MPa, which is bigger than that at 1 000 22 by 9. 4%. In addition, the peak stress becomes bigger with the increase of the thickness of base metal from 1 mm to 8 ram. While the thickness is more than 8 ram, the peak stress varies slightly with the change of the thickness.展开更多
基金Project supported by the Special Funding Support for the Development of 1500 Meter Subsea Christmas Tree and Control System,China。
文摘Improving interfacial bonding and alloying design are effective strategies for enhancing mechanical properties of particle-reinforced steel matrix composites(SMCs).This study prepared SMCs with uniformly distributed TiC_(P)in matrix using master alloying method.The TiC(002)/Fe(011)interface model was established based on the orientation relationship of(011)_(Fe)//(002)_(TiC),and[100]_(Fe)//[100]_(TiC).The effects of single and co-doping of alloying elements(Mn,Cr,Mo,Ni,Cu and Si)on the interface bonding behavior of TiC/Fe in composites were investigated in conjunction with first principles.The results demonstrate that the interface between TiC and matrix is continuous and stable.Compared to the undoped TiC/Fe interface,single-doping Mn,Cr,and Mo can improve the stability of TiC/Fe interface and enhance tensile strength.Conversely,single-doping with Ni,Cu,and Si reduced the interface stability and marginally reduces tensile strength.Relative to the undoped and singly Ni-doped TiC/Fe interfaces,the co-doping Ni-Mo boosts binding energy and separation work at the TiC/Fe interface,which is conducive to the interface bonding between TiC_(P)and matrix,and thus improves the mechanical properties of composites.Thus,in the alloying design of TiC particle reinforced low-alloy SMCs,incorporating Mn,Cr,Mo,and Ni into matrix can enhance the overall mechanical properties of composites.
基金financially sponsored by National Natural Science Foundation of China(51304053)
文摘The segregation behavior of alloying elements X（ X = Zr,V,Cr,Mn,Mo,W,Nb,Y） on the ferrite（ 100） /TiC（ 100） interface has been investigated using first principles method,and the work of separation and interface energy of ferrite / TiC interfaces alloyed by these elements were also analyzed. The results indicated that all these alloying additives except Y were thermodynamically favorable because of the negative segregation energy,showing that they have the tendency to segregate to the ferrite / TiC interface. When the Fe atom in the ferrite /TiC interface is replaced by Y,Zr,or Nb,the adhesive strength of the interface will be weakened due to the lower separation work,larger interfacial energy,and weaker electron effects. However,the introduction of Cr,Mo,W,Mn and V will improve the stability of the ferrite / TiC interface through strong interaction between these elements and C,and Cr-doped interface is the most stable structure. Therefore,the Cr,Mo,W,Mn and V in ferrite side of the interface can effectively promote ferrite heterogeneous nucleation on TiC surface to form fine ferrite grain.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0700900)the National Natural Science Foundation of China(Grant Nos.51571126 and 51861030)+1 种基金the Inner Mongolia Autonomous Region Natural Science Foundation of China(Grant No.2019MS01002)the Inner Mongolia Innovative Research Team of China(Grant No.3400102)。
文摘Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface anisotropy.The calculated results are carefully compared with each other.The interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very thin.However,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises.Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field.The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain wall.The above results calculated by two models are in good agreement with each other.Moreover,the in-plane magnetic moment orientations based on two models are different.The 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are coherent.Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.
基金supported by the National Natural Science Foundation of China-Excellent Young Scholars(No.51922068)National Natural Science Foundation of China(Nos.51821001,51904186,and 51904187)。
文摘The 3D morphologies and growth mechanisms of proeutectic FeAl_(3) at the Al/Fe interface under different cooling rates were studied by synchrotron X-ray tomography.With increasing cooling rate,FeAl_(3) crystals developed from faceted polygonal prism,plates with flat surface,thin ribbon-like with periodic undulating surface to non-faceted rods with radial dendrites in cross section,indicating a gradual interface growth mode transition from two-dimensional layer growth to continuous growth.At a higher cooling rate,twinning mechanism plays a leading role in the formation and growth of FeAl_(3).A link between the morphologies,twinning and crystallographic structure was established based on quantitative analyses on the 3D structures.
基金Project(Q99F01) supported by the Natural Science Foundation of Shandong Province, China
文摘Based on YU’s solids and molecules emperical electron theory(EET), interface valence electron structure of TiC-Fe3Al composites was set up, and the valence electron density of different atomic states TiC and Fe3Al composites in various planes was determined. The results indicate that the electron density of (1 00)Fe3Al is consistent with that of (110)TiC in the first-class a pproximation, the absolute value of minimum electron density difference along the interface is 0.007 37 nm?2, and the relative value is 0.759%. (1 10)TiC //(100)Fe3Al preferred orientation is believed to benefit the formation of the cuboidal shape TiC. In the other hand, it shows that the particle growth is accompanied by the transport of electron, the deviation continuity of electron density intrinsically hinders the grain growth. The electron density of (100)TiC is not consistent with Fe3Al arbitrary crystallographic plane, thus it well explains that the increased titanium and carbon contents do not increase the size of large particles. The crystallographic orientation of (1 10)TiC //(100)Fe3Al will improve the mechanical properties. Therefore interface electron theory is an effective theoretical implement for designing excellent property of composites.
文摘The morphology. orientation relationship and stability of TiC/γ interface in Fe-Cr-Ni base composite synthesized with a liquid state in-situ process have been studied. The TiC/γ interface in as-cast sample is of coherent feature. Its orientation relationship is (020)γ／／(220)TiC, [001]γ||[001]TiC. During the aging at 1473 K, the TiC/γ interface may dissolve in matrix and lamellar M23C6 compound may precipitate from γ-matrix.
基金Funded by the National Natural Science Foundation of China (50672089)the Encouraging Foundation for the Scientific Research of the Excellent Young and Middleaged Scientists in Shandong Province(2006BS04034)
文摘The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.
基金supported by Henan Province Key Research and Development and Promotion Project(Grant No.201ZP20220010).
文摘The effects of vanadium(V)on the microstructures and mechanical properties of the TiC cermet fusion welding interface were studied by adjusting the content of V in the self-developed flux-cored wires using metal inert gas arc(MIG)welding for surfacing on the TiC cermet.The results show that the increase in V content promotes the element diffusion between TiC cermet and weld metal.There are no de-fects observed in the interface,and the diffusion of elements refers to excellent metallurgical bonding.The shear strength of the fusion zone initially decreases and then increases with the increase in V content.The maximum shear strength of the TiC cermet/weld interface,reaching 552 MPa,occurred when the V content reached 0.65%.Meanwhile,the average hardness in the transition zone reached 488.2 HV0.2.
基金Project(BA2006067)supported by Achievement Transitional Foundation of Jiangsu Province,China
文摘A Fe/Al clad tube was prepared by explosive welding.Then the bonding characteristic of the interface was investigated by compression,flattening and compression-shear test.The test results exhibit that the clad tubes possessing good bonding interface have higher shear strength than that of pure aluminum and can bear both axial and radial deformation.The original interface between aluminum layer and ferrite layer was observed by scanning electron microscopy（SEM）.The results show that the clad tubes with good bonding properties possess the interface in wave and straight shape.The Fe/Al clad tube was used to manufacture the T-shape by hydro-bulging.It is found that the good-bonding interface of the Fe/Al clad tube plays a dominant role in the formation of the T-shape.
基金Project supported by National Natural Science Foundation of China(51505393)the National Key Research and Development Plan of China(2017YFB0305905)
文摘Electronic structure, stability and bonding strength of a-Fe/WC interfaces between Ce-doped and undoped WC cermet coating were investigated by first-principles methodology based on densityfunctional theory(DFT). Based on the minimum mismatched lattices, the relatively stable interface that forms between WC(100) and bcc a-Fe(100) was employed to predict the atomic structure, bonding,and ideal work of adhesion. There are three possible positions which were defined as OT, MT, HCP, taking into account both C-and W-terminations. The sequence of structural stability tested in this paper was:MT > OT > HCP. After full relaxation, the results show that only the first and second layers of the interface have significant influence on the electronic structure between Fe and WC. The interaction of Ce elements at the interface is achieved by comparing the interface structure and electronic structure of the doped and undoped interfaces. Ce doped interface possesses a shorter interface distance(d0 = 0.09776 nm)and a larger interface energy(Wad = 8.98 J/m2) than undoped interface(Wad = 8.76 J/m2,d0= 0.10134 nm).Charge density distribution and difference, and density of states were utilized to characterize the electronic properties and determine the interfacial bonding.The results demonstrate that strong covalent bonding existed in the undoped interface, while a mixed covalent/ionic bonding was formed at the Ce-doped interface.
基金The work was supported by the Visiting Scholar Foundation of National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, People's Republic of China.
文摘Phase structure characteristics near the interface of Fe3Al/Q235 diffusion bonding are investigated by means of X raydiffraction (XRD), transmission electronic microscope (TEM) and electron diffraction, etc. The test results indicatedthat obviously a diffusion transition zone forms near the interface of Fe3Al/Q235 under the condition of heatingtemperature 1050~1100℃, holding time 60 min and pressure 9.8 MPa, which indicated that the diffusion interfaceof Fe3Al/Q235 was combined well. The diffusion transition zone consisted of Fe3Al and a-Fe(Al) solid solution.Microhardness near the diffusion transition zone was HM 480~540. There was not brittle phase of high hardness inthe interface transition zone. This is favorable to enhance toughness of Fe3Al/Q235 diffusion joint.
基金sponsored by the National Natural Science Foundation of China(NSFC)(No.52301097)Shanghai Sailing Program(No.23YF1428800)+1 种基金the National Key Research and Development Program of China(Nos.2021YFB3501001 and 2022YFC2905204)Natural Science Foundation of Shenyang(No.23-503-6-05).
文摘In-situ formed TiC particles were introduced into α-Fe matrix as corrosion-resistant phases to enhance corrosion resistance against aluminum melt of the alloy.The effects of TiC content on the microstructure and corrosion behavior of Fe-TiC alloys were examined both experimentally and theoretically.The results indicate that eutectic Fe-6TiC alloy offers superior corrosion resistance to liquid aluminum,which is 7.5 times greater than that of H13 die steel.The long rod-shaped and granular eutectic TiC particles provide superior resistance to aluminum melt diffusion compared to blocky primary TiC.Moreover,these eutectic TiC particles improve the bonding strength of the intermetallic compound layer,inhibiting cracking,peeling,and dissolution of the corrosion layer.A novel theoretical numerical model is established to quantitatively account for the corrosion behavior of the ferrous alloys in aluminum melt,and the diffusion inhibition factor λ and dissolution inhibition factorεare introduced in this work to quantitatively estimate the corrosion performance.Theoretical analysis demonstrates that Fe-6TiC eutectic alloy containing numerous long rod-shaped and granular eutectic TiC exhibits the best corrosion resistance.
文摘The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the interface are greatly increased after 820℃, 2 h water quenching and 450℃, 6 h aging. This result probablycomes from much more U2Ti and U6Ni precipitates along the interface.
基金This study was co-supported by the National Natural Science Foundation of China(No.51771167)the Natural Science Foundation of Hebei Province,China(No.E2021203191)+2 种基金the Hebei Province Innovation Ability Promotion Project,China(No.22567609H)the Natural Science Foundation of Fujian Province,China(No.2020J05196)the Innovative Funding Project for Doctoral Postgraduates of Hebei Province,China(No.CXZZBS2022147).
文摘The preparation of TiC coating on Ti alloy surface to improve the wear resistance has attracted attention from researchers in aerospace field.The service life of TiC coating is related to the interfacial adhesion properties between TiC coating and Ti alloy substrate.However,it is difficult to explain its interfacial adhesion mechanism by experimental methods.Based on the termination of atoms on the TiC surface,two TiC/Ti interface models named as the C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(11)/Ti(0001) interface were constructed by first-principles.The interfacial electronic characteristic of C-Ti bond is a mixture of polar covalent and metal bonds,and that of Ti-Ti bond is the metal bond.The tensile strains of both C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface in the fracture stage are ranged from 12% to 14%.Their maximum tensile stresses are 16.201 GPa and 15.590GPa,respectively.The sliding potential energy surface maximum of C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface are 5.387 J/m^(2) and 0.271 J/m^(2),respectively.And the sliding potential barriers on the minimum energy path are 2.094 J/m2and 0.136 J/m^(2) with an ideal shear strength of 20.32 GPa and 1.61 GPa,respectively.In summary,the interfacial adhesion property of C-terminated-TiC(111)/Ti(0001) interface is better than that of Ti-terminated-TiC(111)/Ti(0001) interface.
基金Supported by the Chinese Academy of Sciences under No.KJ951-A1-401Doctoral Program Foundation from the State Education Committee。
文摘The electronic structure of fcc Fe/Cu{111}interface has been studied by angle-resolved photoemission with synchrotron radiation.The existence of the interface state and absence of intermixture between Fe and Cu atoms in the Fe/Cu{111}interface show that the Fe/Cu{111}system has an abrupt and ordered interface.
基金Project supported by the Nuclear Power Technology Innovation Center ProgramNational Defense Science&Technology Industry,China(Grant No.HDLCXZX-2019-ZH-028)。
文摘Recently,metal-graphene nanocomposite system has aroused much interest due to its radiation tolerance behavior.However,the related atomic mechanism for the metal-graphene interface is still unknown.Further,stainless steels with Fe as main matrix are widely used in nuclear systems.Therefore,in this study,the atomic behaviors of point defects and helium(He) atoms at the Fe(110)-graphene interface are investigated systematically by first principles calculations.The results indicate that graphene interacts strongly with the Fe(110) substrate.In comparison with those of the original graphene and bulk Fe,the formation energy values of C vacancies and Fe point defects decrease significantly for Fe(110)-graphene.However,as He atoms have a high migration barrier and large binding energy at the interface,they are trapped at the interface once they enter into it.These theoretical results suggest that the Fe(110)-graphene interface acts as a strong sink that traps defects,suggesting the potential usage of steel-graphene with multiply interface structures for tolerating the radiation damage.
文摘Fe/C multilayer thin films were deposited by magnetron sputtering. Small angle X-ray diffraction measurements show very well periodicity of the samples. The modulation period determined from a modified Bragg equation agrees well with that determined from deposition rate. The interfacial roughness parameter ξof several samples calculated by X-ray diffraction is between 3.5(?) and 5.6(?).
基金the Doctoral Foundation of Shandong Province (2006BS04004)National Natural Science Foundation of China (50375088)
文摘Fe3Al and Crl8-Ni8 steel were bonded in vacuum and an interface was formed between Fe3Al and Crl8-Ni8 steel. Stress distribution at the diffusion-bonded interface was researched by numerical simulation and finite element method （FEM）. The results indicated that the peak stress appeared at the interface near Cr18-Ni8 steel side. This is the key factor to induce crack at this position. With the enhancement of heating temperature, the peak stress at the bonded interface increases. When the temperature is 1 100 22, the peak stress is up to 65.9 MPa, which is bigger than that at 1 000 22 by 9. 4%. In addition, the peak stress becomes bigger with the increase of the thickness of base metal from 1 mm to 8 ram. While the thickness is more than 8 ram, the peak stress varies slightly with the change of the thickness.
