The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation fo...The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.展开更多
Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BN...Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BNNSs/Ti composites were fabricated by using the warm compaction(WC)technique and rapid heat treatment(HT)strategy on the basis of interfacial nano-TiBw design.The intrinsic structure of BNNSs was well-retained and nano-TiBw on partially reacted BNNSs led to a brilliant interface bond-ing and BNNSs intrinsic strengthening.Tensile tests revealed that 0.1 wt.%BNNSs/Ti composites exhibited the tensile strength(UTS)of 876 MPa(61%higher than pure Ti)and the fracture elongation of 22.6%,demonstrating the well-balanced property.By employing the insitu TEM experiment,we solve an existing debate,uncovering the synergistic toughening effect from BNNSs and interfacial nano-TiBw which effectively inhibited the micro-cracks propagation on BNNSs and heterogeneous interface.This work paves a new way for developing high-performance BNNSs/Ti composites by reaction interface manipulation and underscores the importance of maintaining BNNSs intrinsic structure in the Ti matrix.展开更多
The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological ch...The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological characteristics,their practical applications are constrained by compromised thermal conductivity and insufficient mechanical strength due to the solid solution of a high amount of Ni in the Cu matrix.Cu-Ni matrix composites reinforced with hexagonal boron nitride(h-BN)have garnered significant attention due to their potential for tailored mechanical and thermal properties.However,challenges such as BN agglomerations in Cu-Ni matrix and poor interfacial bonding hinder their practical applications.To address these limitations,this study proposes an innovative fabrication strategy for boron nitride nanosheets(BNNSs)reinforced Cu-Ni composites by integrating the in situ synthesis of BNNSs on Cu powders via chemical vapor deposition with powder metallurgy.Benefited by the in situ strategy,BNNSs with high crystallinity distribute uniformly within the Cu matrix and have an intimate interfacial bonding without voids or other types of defects.Remarkably,the BNNSs/Cu-30%Ni composite achieves simultaneous enhancement in strength and ductility,exhibiting an ultimate tensile strength of 417 MPa and fracture elongation of 17.5%,representing 30%and 118%improvements over pure Cu-Ni alloys,respectively.This exceptional mechanical synergy originates from threefold strengthening mechanisms:grain refinement,mobile dislocation pinning,and efficient stress transfer via robust interfaces.The microstructural analysis confirms that homogenous distribution of BNNSs optimized stress distribution,mitigating strain localization in the composites.Fractographic examination demonstrates uniformly distributed dimples containing embedded BNNSs,indicative of effective crack bridging and deflection during failure.Furthermore,the composite possesses excellent corrosion resistance comparable to matrix alloys,while achieving 21.23%enhancement in thermal conductivity and 20%reduction in coefficient of friction.The scalable fabrication protocol successfully resolves longstanding challenges in BNNSs dispersion and interfacial bonding,offering a viable pathway for designing high-performance CMCs for marine applications.展开更多
The difference in electrochemical behavior between reinforcement and metal matrix usually damages the corrosion resistance of composites.Herein,the coherent BNNSs-AlN-Al transition interface is creatively constructed ...The difference in electrochemical behavior between reinforcement and metal matrix usually damages the corrosion resistance of composites.Herein,the coherent BNNSs-AlN-Al transition interface is creatively constructed in the Aluminium-Boron nitride nanosheets(Al-BNNSs)system based on reactive sintering.It is demonstrated that BNNSs/Al composites exhibit good corrosion resistance via interfacial modification.The BNNSs-AlN-Al transition interface not only optimizes the interfacial structure of BNNSs/Al composites but also significantly enhances the interface bonding strength.Many low-angle grain boundaries(LAGBs)are induced during extrusion due to the pinning effect of strong bonding transition interface.Besides,density functional theory(DFT)calculation and geometric phase analysis(GPA)were executed to clarify the influence of interface design on the corrosion behavior of BNNSs/Al composites.It is found that the transition interface and LAGBs have strong valence electron constraint ability,thus weakening the galvanic effect in composites.Also,the construction of the transition interface reduces the geometrically necessary dislocations and lattice distortion in the grains of Al matrix,avoiding the decrease of corrosion potential of Al matrix.Ultimately,the coupling effect between LAGB and transition interface not only significantly enhances the ion erosion resistance of composites,but also shifts the corrosion mechanism from intergranular corrosion(IGC)to pitting corrosion(PC)in Al matrix.The current work provides a feasible route for the design of aluminum matrix composites(AMCs)with high corrosion resistance.展开更多
基金Jiangsu Province Six Talent Peaks Project(No.2014-XCL-013)Jiangsu Industrial-academicresearch Prospective Joint Project(No.BY2016069-02)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsTop-notch Academic Programs Project of Jiangsu Higher Education Institutions(No.PPZY2015B112)。
文摘The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.
基金the National Natural Science Foundation of China(No.52301186)the Fundamental Research Funds for the Central Universitiesthe Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001).
文摘Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BNNSs/Ti composites were fabricated by using the warm compaction(WC)technique and rapid heat treatment(HT)strategy on the basis of interfacial nano-TiBw design.The intrinsic structure of BNNSs was well-retained and nano-TiBw on partially reacted BNNSs led to a brilliant interface bond-ing and BNNSs intrinsic strengthening.Tensile tests revealed that 0.1 wt.%BNNSs/Ti composites exhibited the tensile strength(UTS)of 876 MPa(61%higher than pure Ti)and the fracture elongation of 22.6%,demonstrating the well-balanced property.By employing the insitu TEM experiment,we solve an existing debate,uncovering the synergistic toughening effect from BNNSs and interfacial nano-TiBw which effectively inhibited the micro-cracks propagation on BNNSs and heterogeneous interface.This work paves a new way for developing high-performance BNNSs/Ti composites by reaction interface manipulation and underscores the importance of maintaining BNNSs intrinsic structure in the Ti matrix.
基金financial support of the National Key R&D Program of China(No.SQ2024YFA1200082)the National Natural Science Foundation of China(No.52371013)the Natural Science Foundation of Tianjin City(No.22JCZDJC00020).
文摘The rapid expansion of marine industries has created an urgent demand for advanced engineering materials with superior multifunctional performance.While Cu-Ni alloys demonstrate favorable stability and tribological characteristics,their practical applications are constrained by compromised thermal conductivity and insufficient mechanical strength due to the solid solution of a high amount of Ni in the Cu matrix.Cu-Ni matrix composites reinforced with hexagonal boron nitride(h-BN)have garnered significant attention due to their potential for tailored mechanical and thermal properties.However,challenges such as BN agglomerations in Cu-Ni matrix and poor interfacial bonding hinder their practical applications.To address these limitations,this study proposes an innovative fabrication strategy for boron nitride nanosheets(BNNSs)reinforced Cu-Ni composites by integrating the in situ synthesis of BNNSs on Cu powders via chemical vapor deposition with powder metallurgy.Benefited by the in situ strategy,BNNSs with high crystallinity distribute uniformly within the Cu matrix and have an intimate interfacial bonding without voids or other types of defects.Remarkably,the BNNSs/Cu-30%Ni composite achieves simultaneous enhancement in strength and ductility,exhibiting an ultimate tensile strength of 417 MPa and fracture elongation of 17.5%,representing 30%and 118%improvements over pure Cu-Ni alloys,respectively.This exceptional mechanical synergy originates from threefold strengthening mechanisms:grain refinement,mobile dislocation pinning,and efficient stress transfer via robust interfaces.The microstructural analysis confirms that homogenous distribution of BNNSs optimized stress distribution,mitigating strain localization in the composites.Fractographic examination demonstrates uniformly distributed dimples containing embedded BNNSs,indicative of effective crack bridging and deflection during failure.Furthermore,the composite possesses excellent corrosion resistance comparable to matrix alloys,while achieving 21.23%enhancement in thermal conductivity and 20%reduction in coefficient of friction.The scalable fabrication protocol successfully resolves longstanding challenges in BNNSs dispersion and interfacial bonding,offering a viable pathway for designing high-performance CMCs for marine applications.
基金financially supported by the Yunnan Fundamental Research Projects(Nos.202501CF070047&202401AU070165)Yunnan International Cooperation Base in Cloud Computation for Non-ferrous Metal Processing(No.202203AE140011).
文摘The difference in electrochemical behavior between reinforcement and metal matrix usually damages the corrosion resistance of composites.Herein,the coherent BNNSs-AlN-Al transition interface is creatively constructed in the Aluminium-Boron nitride nanosheets(Al-BNNSs)system based on reactive sintering.It is demonstrated that BNNSs/Al composites exhibit good corrosion resistance via interfacial modification.The BNNSs-AlN-Al transition interface not only optimizes the interfacial structure of BNNSs/Al composites but also significantly enhances the interface bonding strength.Many low-angle grain boundaries(LAGBs)are induced during extrusion due to the pinning effect of strong bonding transition interface.Besides,density functional theory(DFT)calculation and geometric phase analysis(GPA)were executed to clarify the influence of interface design on the corrosion behavior of BNNSs/Al composites.It is found that the transition interface and LAGBs have strong valence electron constraint ability,thus weakening the galvanic effect in composites.Also,the construction of the transition interface reduces the geometrically necessary dislocations and lattice distortion in the grains of Al matrix,avoiding the decrease of corrosion potential of Al matrix.Ultimately,the coupling effect between LAGB and transition interface not only significantly enhances the ion erosion resistance of composites,but also shifts the corrosion mechanism from intergranular corrosion(IGC)to pitting corrosion(PC)in Al matrix.The current work provides a feasible route for the design of aluminum matrix composites(AMCs)with high corrosion resistance.
