Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks ...Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.展开更多
A novel friction stir double-riveting welding(FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum(Al) and lower copper(Cu) plates,and this technology employed a Cu column as a...A novel friction stir double-riveting welding(FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum(Al) and lower copper(Cu) plates,and this technology employed a Cu column as a rivet and a specially designed welding tool with a large concave-angle shoulder. The formations, interfacial characteristics, mechanical properties and fracture features of Al/Cu FSDRW joints under different rotational velocities and dwell times were investigated. The results showed that the well-formed FSDRW joint was successfully obtained.The cylindrical Cu column was transformed into a double riveting heads structure with a Cu anchor at the top and an Al anchor at the bottom, thereby providing an excellent mechanical interlocking.The defect-free Cu/Cu interface was formed at the lap interface due to the sufficient metallurgical bonding between the Cu column and the Cu plate, thereby effectively inhibiting the propagation of crack from the intermetallic compound layer at the lap interface between the Al and Cu plates. The tensile shear load of joint was increased first and then decreased when the rotational velocity and dwell time of welding tool increased, and the maximum value was 5.52 k N. The FSDRW joint presented a mixed mode of ductile and brittle fractures.展开更多
In order to achieve a high-quality joining of aluminum(Al)and copper(Cu)dissimilar metals,a new friction stir doubleriveting welding(FSDRW)with a Cu rod as the rivet was proposed,and the rotating tool with a large con...In order to achieve a high-quality joining of aluminum(Al)and copper(Cu)dissimilar metals,a new friction stir doubleriveting welding(FSDRW)with a Cu rod as the rivet was proposed,and the rotating tool with a large concave angle shoulder was specially designed.The results showed that under the thermal–mechanical effect of rotating tool,the Cu rod was deformed to be a double riveting heads structure with a Cu anchor at the upper surface of Al plate and an Al anchor above the lap interface of joint,and these two anchors greatly enhanced the mechanical interlocking of Al/Cu joint.The effective bonding interfaces were formed among the double riveting heads structure,the upper Al plate and the lower Cu plate,which contained the Cu/Cu interface and the Al/Cu interface.The Cu/Cu interface without the kissing bond and the Al/Cu interface with the rationally thin AlCu and Al_(2)Cu intermetallic compounds(IMCs)layers were beneficial to heightening the joint tensile shear strength.The maximum tensile shear load of the FSDRW joint achieved 5.52 kN,and the joint under different plunging depths of rotating tool presented a mixed mode of ductile fracture and brittle fracture.This novel FSDRW technique owns the advantages of strong mechanical interlocking and superb metallurgical bonding,and provides a new approach to acquiring a high-quality Al/Cu dissimilar metals joint.展开更多
In this study,the cold-spraying process was utilized to deposit Al particles onto an Al slab,an Mg slab,and both Al and Mg slabs to form an ultra-thin interlayer,and then the clad slabs were rolled at 400℃,developing...In this study,the cold-spraying process was utilized to deposit Al particles onto an Al slab,an Mg slab,and both Al and Mg slabs to form an ultra-thin interlayer,and then the clad slabs were rolled at 400℃,developing three roll-bonding processes:the roll-bonding process with cold-sprayed Al powder on the Al slab(CS-Al),the roll-bonding process with cold-sprayed Al powder on the Mg slab(CS-Mg),and the rollbonding process with cold-sprayed Al powder on both the Al slab and the Mg slab(CS-Both).The effects of three different cold-sprayed Al particle interlayer processes on the mechanical properties of rolled Mg/Al clad plates were investigated to improve the mechanical properties.The microstructure,texture evolution,intermetallic compound formation,mechanical properties,and mechanisms involved in the Mg/Al clad plate rolling were systematically investigated.The results showed that the pre-bonding between the particles and the substrates through coldspraying had a significant impact on the bonding strength of the Mg/Al clad plates,and the CS-Both process can increase the average shear strength of the Mg/Al clad plates to 49.24 MPa at a medium reduction rate of 37.5%,2.5 times that of the conventional rolling process.The CS-Both process constructed more evident dual microscopic three-dimensional interfaces and promoted more thorough atomic diffusion at the interface through the double-sided cold-spraying process.Meanwhile,the dual cold-sprayed Al coatings on both the Mg slab and Al slab underwent dynamic recrystallization during rolling to form a homogeneous unit with no additional coating interfaces.Fine grain strengthening and dislocation strengthening were judged to be important mechanisms for improving the mechanical performance of the interfacial layer.展开更多
Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRP...Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRPs)through laser-assisted metal and plastic direct joining(LAMP).This study uses the LAMP technique to produce AZ31-CFRP joints.The joining process involves as-received AZ31,HFpretreated AZ31,and thermally oxidized HF-pretreated AZ31 alloy sheets.Furthermore,the bonding strength of joints prepared with thermally oxidized AZ31 alloy sheets is examined to ascertain the combined effect of HF treatment and thermal oxidation on bonding strength.The microstructures,surface chemical interactions,and mechanical performances of joints are investigated under tensile shear loading.Various factors,such as bubble formation,CFRP resin decomposition,and mechanical interlocking considerably affect joint strength.Additionally,surface chemical interactions between the active species on metal parts and the polar amide along with carbonyl groups of polymer play a significant role in improving joint strength.Joints prepared with surface-pretreated AZ31 alloy sheets show significant improvements in bonding strength.展开更多
The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot welding.The effects of rotation speed and pressure speed on weld formin...The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot welding.The effects of rotation speed and pressure speed on weld forming,tensile strength,and welded joint structure were analyzed in different welding modes.The results indicated two different connection modes:the chimeric mode and the non-chimeric mode.The corresponding depression depth are 2 and 2.4 mm,respectively.In the non-chimeric connection mode,the steel/aluminum metallurgical interface is a smooth transition,the hook structure is obvious,and the welding mechanism mainly depends on the mutual diffusion between atoms.However,in the chimeric mode,a hook structure will be formed at the metallurgical interface of steel and aluminum.The connection mechanism is determined by mechanical interlocking and mutual diffusion.The maximum strength value is 7.48 kN in non-chimeric mode.At this time,the spindle speed is 1300 r/min and the pressure speed is 1 mm/s.There were two types of fractures:the button fracture mode and the peel fracture mode.展开更多
The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transitio...The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.展开更多
Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e...Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e., AIEgens) has been witnessed. The combination of AIEgens and rotaxanes leads to the successful construction of a novel type of luminescent rotaxanes with many attractive features. In particular, the unique controllable dynamic feature of rotaxanes endows the resultant AIEgen-based rotaxanes precisely tunable emissions under external stimuli, leading to the construction of a novel type of smart luminescent materials. In this minireview, the recent progress of AIEgen-based rotaxanes has been summarized, with an emphasis on the design strategy and potential applications.展开更多
Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings o...Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calculations.The mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling effect.The interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)lithiation.The positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+diffusion.Therefore,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.展开更多
Natural molecular machines have inspired the development of artificial molecular machines,which have the potential to revolutionize several areas of technology.Artificial molecular machines commonly employ molecular s...Natural molecular machines have inspired the development of artificial molecular machines,which have the potential to revolutionize several areas of technology.Artificial molecular machines commonly employ molecular switches,molecular motors,and molecular shuttles as fundamental building blocks.The observation of artificial molecular machines constructed by these building blocks can be highly challenging due to their small sizes and intricate behaviors.The use of modern instrumentation and advanced observational techniques plays a crucial role in the observation and characterization of molecular machines.Furthermore,a well-designed molecular structure is also a critical factor in making molecular ma-chines more observable.This review summarizes the common methods from diverse perspectives used to observe molecular machines and emphasizes the significance of comprehending their behaviors in the design of superior artificial molecular machines.展开更多
Oligo[n]rotaxanes are one of the most extensively studied categories of mechanically bonded macromolecules.In this study,a supramolecular oligo[2]rotaxane is successfully constructed driven by platinum(Ⅱ)metallacycle...Oligo[n]rotaxanes are one of the most extensively studied categories of mechanically bonded macromolecules.In this study,a supramolecular oligo[2]rotaxane is successfully constructed driven by platinum(Ⅱ)metallacycle and pillar[5]arene-based host–vip interactions in an orthogonal way.The supramolecular oligo[2]rotaxane is further applied in fabricating a light harvesting system.展开更多
Supramolecular polymers,as a type of dynamic polymers,are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry,whose development has greatly promoted the prosperity of new mater...Supramolecular polymers,as a type of dynamic polymers,are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry,whose development has greatly promoted the prosperity of new materials.Notably,molecular weight is one of the most important parameters of supramolecular polymers,which affects the physical/chemical properties and processing applications of materials.Developing new methods for characterizing the molecular weight of supramolecular polymers is crucial for advancing the development of supramolecular polymers.In this review,we elaborate and summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers,including(1)the molecular weight distinction corresponding to variable fluorescence colors,(2)matching different molecular weights with different fluorescence lifetime,(3)transforming supramolecular polymers into mechanically interlocked polymers or covalent polymers.Besides,we also discuss the limitations of current methods for characterizing supramolecular polymers.We hope that this review can promote the development of supramolecular polymers and significantly inspire to exploit new methods to characterizing molecular weight of supramolecular polymers.展开更多
The design and synthesis of two-dimensional(2D)polymers have received notable attention over the past two decades because of their unique structural properties and wide range of applications,such as molecular separati...The design and synthesis of two-dimensional(2D)polymers have received notable attention over the past two decades because of their unique structural properties and wide range of applications,such as molecular separation,nanoelectronics,sensing,and optoelectronics[1].The regularity of 2D polymeric networks,especially when high crystallinity is formed,allows them to control their pore sizes,surface areas,and mechanical properties,keeping them at the forefront of materials chemistry and nanotechnology[2,3].展开更多
Mechanically interlocked molecules(MIMs)and host–vip chemistry have received great attention in the past few decades.However,it remains challenging to design architectures with mechanically interlocked features and...Mechanically interlocked molecules(MIMs)and host–vip chemistry have received great attention in the past few decades.However,it remains challenging to design architectures with mechanically interlocked features and construct cavities for vip molecule recognition using similar building blocks.In this study,we designed and constructed a series of novel twisted supramolecular structures by assembling various multitopic terpyridine(tpy)ligands with the same diameter and Zn(II)ions.The obtained complexes exhibited evolutional architectures and showed distinctively different space-constraint effects.Specifically,the assembled dimer SA,SB,and SBH displayed mechanically interlocked phenomena,including[2]catenane and[3]catenane,with an increase in concentration.However,no interlocked structures were observed in complexes SC and SCH constructed by hexatopic tpy ligands due to the significant space constraints.The single-crystal data of complex SCH further proved significant space constraints and illustrated the formation of a relatively closed cavity,which showed excellent host–vip properties for different calixarenes,especially high affinity for calix[6]arene.展开更多
The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a ma...The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a macrocycle)can occur inside the free volume pore of the MOF.To aid in the preparation of such materials,reticular synthesis was used herein to design rigid molecular building blocks with predetermined ordered structures starting from the well-known MOF NOTT-101.New linkers were synthesized that have a T-shape,based on a triphenylene tetra-carboxylate strut,and their incorporation into Cu(II)-based MOFs was investigated.The single-crystal structures of three new MOFs,UWCM-12(fof),β-UWCM-13(loz),UWCM-14(lil),with naked T-shaped linkers were determined;β-UWCM-13 is the first reported example of the loz topology.A fourth MOF,UWDM-14(lil)is analogous to UWCM-14(lil)but contains a[2]rotaxane linker.Variable-temperature,^(2)H solid-state NMR was used to probe the dynamics of a 24-membered macrocycle threaded onto the MOF skeleton.展开更多
Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental condit...Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental conditions.To surmount the limitations of conventional cross-linking modes,mechanical bonds stabilized by host-vip recognition are incorporated as the cross-linking points of SBR to form mechanically interlocked networks(MINs).Compared with covalently cross-linked network,the representative MIN exhibits superior mechanical performance in terms of elongation(1392%)and breaking strength(4.6 MPa),whose toughness has surged by 17 times.Dissociation of host-vip recognition and subsequent sliding motion provide an effective energy dissipation mechanism,and the release of hidden length is also beneficial to enhance toughness.Furthermore,the introduction of the rotaxane cross-links made the network more pliable and possess damping and elastic properties,which can return to initial state with one minute rest interval.We aspire that this direct introduction method can serve as a blueprint,offering valuable insights for the enhancement of mechanical properties in conventional commercial polymer materials.展开更多
Intermetallic compounds produced in laser additive manufacturing are the main factors restricting the joint performance of dissimilar metals.To solve this problem,a dual molten pool interface interlocking mechanism wa...Intermetallic compounds produced in laser additive manufacturing are the main factors restricting the joint performance of dissimilar metals.To solve this problem,a dual molten pool interface interlocking mechanism was proposed in this study.Based on a dual molten pool interface interlocking mechanism,the dissimilar metals,aluminum alloy and stainless steel,were produced as single-layer and multilayer samples,using the wire-feed laser additive manufacturing directed energy deposition technology.The preferred parameters for the dual molten pool interface interlocking mechanism process of the dissimilar metals,aluminum alloy and stainless steel,were obtained.The matching relationship between the interface connection of dissimilar metals and the process parameters was established.The results demonstrated excellent mechanical occlusion at the connection interface and no apparent intermetallic compound layer.Good feature size and high microhardness were observed under a laser power of 660 W,a wire feeding speed of 55 mm/s,and a platform moving speed of 10 mm/s.Molecular dynamics simulations demonstrated a faster rate of aluminum diffusion in the aluminum alloy substrate to stainless steel under the action of the initial contact force than without the initial contact force.Thus,the dual molten pool interface interlocking mechanism can effectively reduce the intermetallic compound layer when dissimilar metals are connected in the aerospace field.展开更多
Selective laser melting(SLM)is a promising technology for fabricating complex components with W/Cu dual metal.To enhance the interfacial bonding of W/Cu dual metal,we propose a novel approach using laser texturing to ...Selective laser melting(SLM)is a promising technology for fabricating complex components with W/Cu dual metal.To enhance the interfacial bonding of W/Cu dual metal,we propose a novel approach using laser texturing to fabricate micro/nanostructures on the W surface.The micro/nanostructures promoted the spreading of Cu in the liquid,inhibited defects,and considerably increased the contact area between W and Cu by mechanical interlocking.To the best of our knowledge,a W/Cu dual metal was successfully prepared by SLM without a transition layer the first time.The bonding strength of the two materials reached 123 MPa,close to that of a W/Cu dual metal joint prepared by diffusion bonding.展开更多
Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and tran...Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level.However,the investigations on their mechanical properties are lagging far behind their structural fabrication,especially for linear polyrotaxanes in bulk.Herein,we report stretchable poly[2]rotaxane elastomers(PREs)which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties.Specifically,we have synthesized a hydroxyfunctionalized[2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs.Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane,the representative PRE exhibits favorable mechanical performance in terms of stretchability(∼1200%),Young’s modulus(24.6 MPa),and toughness(49.5 MJ/m^(3)).Moreover,we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties.It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−vip interaction and consequential sliding motion of the wheel along the axle in the[2]rotaxane motif.展开更多
基金supported by the National Research Foundation of Korea(NRF)Grant(RS-2024-00343512,RS-2024-00416938).
文摘Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.
基金supported by the National Natural Science Foundation of China(Nos.51874201 and 52074184).
文摘A novel friction stir double-riveting welding(FSDRW) technology was proposed in order to realize the high-quality joining of upper aluminum(Al) and lower copper(Cu) plates,and this technology employed a Cu column as a rivet and a specially designed welding tool with a large concave-angle shoulder. The formations, interfacial characteristics, mechanical properties and fracture features of Al/Cu FSDRW joints under different rotational velocities and dwell times were investigated. The results showed that the well-formed FSDRW joint was successfully obtained.The cylindrical Cu column was transformed into a double riveting heads structure with a Cu anchor at the top and an Al anchor at the bottom, thereby providing an excellent mechanical interlocking.The defect-free Cu/Cu interface was formed at the lap interface due to the sufficient metallurgical bonding between the Cu column and the Cu plate, thereby effectively inhibiting the propagation of crack from the intermetallic compound layer at the lap interface between the Al and Cu plates. The tensile shear load of joint was increased first and then decreased when the rotational velocity and dwell time of welding tool increased, and the maximum value was 5.52 k N. The FSDRW joint presented a mixed mode of ductile and brittle fractures.
基金financially supported by the National Natural Science Foundation of China(Nos.51874201 and 52074184).
文摘In order to achieve a high-quality joining of aluminum(Al)and copper(Cu)dissimilar metals,a new friction stir doubleriveting welding(FSDRW)with a Cu rod as the rivet was proposed,and the rotating tool with a large concave angle shoulder was specially designed.The results showed that under the thermal–mechanical effect of rotating tool,the Cu rod was deformed to be a double riveting heads structure with a Cu anchor at the upper surface of Al plate and an Al anchor above the lap interface of joint,and these two anchors greatly enhanced the mechanical interlocking of Al/Cu joint.The effective bonding interfaces were formed among the double riveting heads structure,the upper Al plate and the lower Cu plate,which contained the Cu/Cu interface and the Al/Cu interface.The Cu/Cu interface without the kissing bond and the Al/Cu interface with the rationally thin AlCu and Al_(2)Cu intermetallic compounds(IMCs)layers were beneficial to heightening the joint tensile shear strength.The maximum tensile shear load of the FSDRW joint achieved 5.52 kN,and the joint under different plunging depths of rotating tool presented a mixed mode of ductile fracture and brittle fracture.This novel FSDRW technique owns the advantages of strong mechanical interlocking and superb metallurgical bonding,and provides a new approach to acquiring a high-quality Al/Cu dissimilar metals joint.
基金funded by the National Natural Science Foundation of China(Grant No.52305405,52075359)the Natural Science Foundation Research Program of Shanxi Province(Grant No.202203021222121)+1 种基金the Fund for Shanxi“1331Project”Key Innovative Research Teamthe Chinese Postdoctoral Science Foundation(Grant No.2021M702544)。
文摘In this study,the cold-spraying process was utilized to deposit Al particles onto an Al slab,an Mg slab,and both Al and Mg slabs to form an ultra-thin interlayer,and then the clad slabs were rolled at 400℃,developing three roll-bonding processes:the roll-bonding process with cold-sprayed Al powder on the Al slab(CS-Al),the roll-bonding process with cold-sprayed Al powder on the Mg slab(CS-Mg),and the rollbonding process with cold-sprayed Al powder on both the Al slab and the Mg slab(CS-Both).The effects of three different cold-sprayed Al particle interlayer processes on the mechanical properties of rolled Mg/Al clad plates were investigated to improve the mechanical properties.The microstructure,texture evolution,intermetallic compound formation,mechanical properties,and mechanisms involved in the Mg/Al clad plate rolling were systematically investigated.The results showed that the pre-bonding between the particles and the substrates through coldspraying had a significant impact on the bonding strength of the Mg/Al clad plates,and the CS-Both process can increase the average shear strength of the Mg/Al clad plates to 49.24 MPa at a medium reduction rate of 37.5%,2.5 times that of the conventional rolling process.The CS-Both process constructed more evident dual microscopic three-dimensional interfaces and promoted more thorough atomic diffusion at the interface through the double-sided cold-spraying process.Meanwhile,the dual cold-sprayed Al coatings on both the Mg slab and Al slab underwent dynamic recrystallization during rolling to form a homogeneous unit with no additional coating interfaces.Fine grain strengthening and dislocation strengthening were judged to be important mechanisms for improving the mechanical performance of the interfacial layer.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Science and ICT(RS-2023-00234757).
文摘Although hydrofluoric acid(HF)surface treatment is known to enhance the joining of metals with polymers,there is limited information on its effect on the joining of AZ31 alloy and carbon-fiber-reinforced plastics(CFRPs)through laser-assisted metal and plastic direct joining(LAMP).This study uses the LAMP technique to produce AZ31-CFRP joints.The joining process involves as-received AZ31,HFpretreated AZ31,and thermally oxidized HF-pretreated AZ31 alloy sheets.Furthermore,the bonding strength of joints prepared with thermally oxidized AZ31 alloy sheets is examined to ascertain the combined effect of HF treatment and thermal oxidation on bonding strength.The microstructures,surface chemical interactions,and mechanical performances of joints are investigated under tensile shear loading.Various factors,such as bubble formation,CFRP resin decomposition,and mechanical interlocking considerably affect joint strength.Additionally,surface chemical interactions between the active species on metal parts and the polar amide along with carbonyl groups of polymer play a significant role in improving joint strength.Joints prepared with surface-pretreated AZ31 alloy sheets show significant improvements in bonding strength.
基金National Natural Science Foundation of China(No.52275306)Beijing Municipal Natural Science Foundation(No.3232021)for their support.
文摘The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot welding.The effects of rotation speed and pressure speed on weld forming,tensile strength,and welded joint structure were analyzed in different welding modes.The results indicated two different connection modes:the chimeric mode and the non-chimeric mode.The corresponding depression depth are 2 and 2.4 mm,respectively.In the non-chimeric connection mode,the steel/aluminum metallurgical interface is a smooth transition,the hook structure is obvious,and the welding mechanism mainly depends on the mutual diffusion between atoms.However,in the chimeric mode,a hook structure will be formed at the metallurgical interface of steel and aluminum.The connection mechanism is determined by mechanical interlocking and mutual diffusion.The maximum strength value is 7.48 kN in non-chimeric mode.At this time,the spindle speed is 1300 r/min and the pressure speed is 1 mm/s.There were two types of fractures:the button fracture mode and the peel fracture mode.
基金supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06).
文摘The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.
基金financial support sponsored by the National Natural Science Foundation of China(No.22001073)the Fundamental Research Funds for the Central Universitiesthe Research Fund Program of Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices(No.2020-GDKLFSHMD-07)。
文摘Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e., AIEgens) has been witnessed. The combination of AIEgens and rotaxanes leads to the successful construction of a novel type of luminescent rotaxanes with many attractive features. In particular, the unique controllable dynamic feature of rotaxanes endows the resultant AIEgen-based rotaxanes precisely tunable emissions under external stimuli, leading to the construction of a novel type of smart luminescent materials. In this minireview, the recent progress of AIEgen-based rotaxanes has been summarized, with an emphasis on the design strategy and potential applications.
基金U.S.Department of Energy,Office of Basic Energy Sciences,Grant/Award Number:DE-FG02-17ER16362。
文摘Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calculations.The mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling effect.The interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)lithiation.The positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+diffusion.Therefore,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.
基金supported by“Zhishan”Scholars Programs of Southeast University,Jiangsu Innovation Team Program,and the Fundamental Research Funds for the Central Universities.
文摘Natural molecular machines have inspired the development of artificial molecular machines,which have the potential to revolutionize several areas of technology.Artificial molecular machines commonly employ molecular switches,molecular motors,and molecular shuttles as fundamental building blocks.The observation of artificial molecular machines constructed by these building blocks can be highly challenging due to their small sizes and intricate behaviors.The use of modern instrumentation and advanced observational techniques plays a crucial role in the observation and characterization of molecular machines.Furthermore,a well-designed molecular structure is also a critical factor in making molecular ma-chines more observable.This review summarizes the common methods from diverse perspectives used to observe molecular machines and emphasizes the significance of comprehending their behaviors in the design of superior artificial molecular machines.
基金financially supported by the National Natural Science Foundation of China(Nos.22001214,21662031,21661028,22061039)the Science Fund for Distinguished Young Scholars of Gansu Province(No.22JR5RA131)+3 种基金the Longyuan Innovation and Entrepreneurship Talent Project of Gansu Provincethe Major Project Cultivation Program of Northwest Normal University(No.NWNU-LKZD2022-01)the Top Leading Talents Project of Gansu Province,the Key R&D Program of Gansu Province(No.21YF5GA066)Gansu Province College Industry Support Plan Project(No.2022CYZC-18)。
文摘Oligo[n]rotaxanes are one of the most extensively studied categories of mechanically bonded macromolecules.In this study,a supramolecular oligo[2]rotaxane is successfully constructed driven by platinum(Ⅱ)metallacycle and pillar[5]arene-based host–vip interactions in an orthogonal way.The supramolecular oligo[2]rotaxane is further applied in fabricating a light harvesting system.
基金supported by the National Natural Science Foundation of China(No.22001087)supported by Fundamental Research Funds for the Central Universities(No.2020kfy XJJS013)Interdisciplinary Research Program of HUST(No.2023JCYJ013)。
文摘Supramolecular polymers,as a type of dynamic polymers,are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry,whose development has greatly promoted the prosperity of new materials.Notably,molecular weight is one of the most important parameters of supramolecular polymers,which affects the physical/chemical properties and processing applications of materials.Developing new methods for characterizing the molecular weight of supramolecular polymers is crucial for advancing the development of supramolecular polymers.In this review,we elaborate and summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers,including(1)the molecular weight distinction corresponding to variable fluorescence colors,(2)matching different molecular weights with different fluorescence lifetime,(3)transforming supramolecular polymers into mechanically interlocked polymers or covalent polymers.Besides,we also discuss the limitations of current methods for characterizing supramolecular polymers.We hope that this review can promote the development of supramolecular polymers and significantly inspire to exploit new methods to characterizing molecular weight of supramolecular polymers.
文摘The design and synthesis of two-dimensional(2D)polymers have received notable attention over the past two decades because of their unique structural properties and wide range of applications,such as molecular separation,nanoelectronics,sensing,and optoelectronics[1].The regularity of 2D polymeric networks,especially when high crystallinity is formed,allows them to control their pore sizes,surface areas,and mechanical properties,keeping them at the forefront of materials chemistry and nanotechnology[2,3].
基金supported by the National Natural Science Foundation of China(grant no.22071079 for M.W.)Guangdong Natural Science Foundation(grant no.2019A1515011358 for Z.Z.)Science and Technology Research Project of Guangzhou(grant no.202002030257 for Z.Z).
文摘Mechanically interlocked molecules(MIMs)and host–vip chemistry have received great attention in the past few decades.However,it remains challenging to design architectures with mechanically interlocked features and construct cavities for vip molecule recognition using similar building blocks.In this study,we designed and constructed a series of novel twisted supramolecular structures by assembling various multitopic terpyridine(tpy)ligands with the same diameter and Zn(II)ions.The obtained complexes exhibited evolutional architectures and showed distinctively different space-constraint effects.Specifically,the assembled dimer SA,SB,and SBH displayed mechanically interlocked phenomena,including[2]catenane and[3]catenane,with an increase in concentration.However,no interlocked structures were observed in complexes SC and SCH constructed by hexatopic tpy ligands due to the significant space constraints.The single-crystal data of complex SCH further proved significant space constraints and illustrated the formation of a relatively closed cavity,which showed excellent host–vip properties for different calixarenes,especially high affinity for calix[6]arene.
基金S.J.L.acknowledges the Natural Sciences and Engineering Research Council of Canada for support of a Discovery Grant(101694)and a Canada Research Chair.R.W.S.is also grateful for support from NSERC,the Canadian Foundation for Innovation,the Ontario Innovation Trust,the University of Windsor for the development and maintenance of the SSNMR centre,and for funding from the Florida State University and the National High Magnetic Field Laboratory(NHMFL),which is funded by the National Science Foundation Cooperative Agreement(DM R-1644779)and by the State of Florida.The authors acknowledge M.Revington for technical assistance with solution NM Rspectroscopy and J.Auld for technical assistance with high resolution mass spectrometry.
文摘The concept of“robust dynamics”describes the incorporation of mechanically interlocked molecules(MIMs)into metal-organic framework(MOF)materials such that large amplitude motions(e.g.,rotation or translation of a macrocycle)can occur inside the free volume pore of the MOF.To aid in the preparation of such materials,reticular synthesis was used herein to design rigid molecular building blocks with predetermined ordered structures starting from the well-known MOF NOTT-101.New linkers were synthesized that have a T-shape,based on a triphenylene tetra-carboxylate strut,and their incorporation into Cu(II)-based MOFs was investigated.The single-crystal structures of three new MOFs,UWCM-12(fof),β-UWCM-13(loz),UWCM-14(lil),with naked T-shaped linkers were determined;β-UWCM-13 is the first reported example of the loz topology.A fourth MOF,UWDM-14(lil)is analogous to UWCM-14(lil)but contains a[2]rotaxane linker.Variable-temperature,^(2)H solid-state NMR was used to probe the dynamics of a 24-membered macrocycle threaded onto the MOF skeleton.
基金the financial support of the National Natural Science Foundation of China(22071152 and 22122105)the financial support of the National Natural Science Foundation of China(22305150)+4 种基金the financial support from the National Natural Science Foundation of China(22101175 and 52333001)Natural Science Foundation of Shanghai(22dz1207603)supported by the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(SN-ZJU-SIAS-006)State Key Laboratory of Polyolefins and Catalysis and Shanghai Key Laboratory of Catalysis Technology for Polyolefins(SKL-LCTP-202301)the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22SG11)。
文摘Styrene-butadiene rubber(SBR)is an indispensable material in modern society,and the necessity for enhanced mechanical properties in SBR persists,particularly to withstand the rigors of challenging environmental conditions.To surmount the limitations of conventional cross-linking modes,mechanical bonds stabilized by host-vip recognition are incorporated as the cross-linking points of SBR to form mechanically interlocked networks(MINs).Compared with covalently cross-linked network,the representative MIN exhibits superior mechanical performance in terms of elongation(1392%)and breaking strength(4.6 MPa),whose toughness has surged by 17 times.Dissociation of host-vip recognition and subsequent sliding motion provide an effective energy dissipation mechanism,and the release of hidden length is also beneficial to enhance toughness.Furthermore,the introduction of the rotaxane cross-links made the network more pliable and possess damping and elastic properties,which can return to initial state with one minute rest interval.We aspire that this direct introduction method can serve as a blueprint,offering valuable insights for the enhancement of mechanical properties in conventional commercial polymer materials.
基金supported by the National Natural Science Foundation of China(Grant No.51901162)the support of the National Talent Program of China。
文摘Intermetallic compounds produced in laser additive manufacturing are the main factors restricting the joint performance of dissimilar metals.To solve this problem,a dual molten pool interface interlocking mechanism was proposed in this study.Based on a dual molten pool interface interlocking mechanism,the dissimilar metals,aluminum alloy and stainless steel,were produced as single-layer and multilayer samples,using the wire-feed laser additive manufacturing directed energy deposition technology.The preferred parameters for the dual molten pool interface interlocking mechanism process of the dissimilar metals,aluminum alloy and stainless steel,were obtained.The matching relationship between the interface connection of dissimilar metals and the process parameters was established.The results demonstrated excellent mechanical occlusion at the connection interface and no apparent intermetallic compound layer.Good feature size and high microhardness were observed under a laser power of 660 W,a wire feeding speed of 55 mm/s,and a platform moving speed of 10 mm/s.Molecular dynamics simulations demonstrated a faster rate of aluminum diffusion in the aluminum alloy substrate to stainless steel under the action of the initial contact force than without the initial contact force.Thus,the dual molten pool interface interlocking mechanism can effectively reduce the intermetallic compound layer when dissimilar metals are connected in the aerospace field.
基金supported by the Key Research and Development Program of the Anhui Province(202004b11020030).
文摘Selective laser melting(SLM)is a promising technology for fabricating complex components with W/Cu dual metal.To enhance the interfacial bonding of W/Cu dual metal,we propose a novel approach using laser texturing to fabricate micro/nanostructures on the W surface.The micro/nanostructures promoted the spreading of Cu in the liquid,inhibited defects,and considerably increased the contact area between W and Cu by mechanical interlocking.To the best of our knowledge,a W/Cu dual metal was successfully prepared by SLM without a transition layer the first time.The bonding strength of the two materials reached 123 MPa,close to that of a W/Cu dual metal joint prepared by diffusion bonding.
基金supported by grants from the National Natural Science Foundation of China(22122105,22071152,and 21901161)Natural Science Foundation of Shanghai(20ZR1429200 and 22YF1400800)supported by the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(SN-ZJU-SIAS-006).
文摘Mechanically interlocked polymers(MIPs)are promising candidates for the construction of elastomeric materials with desirable mechanical performance on account of their abilities to undergo inherent rotational and translational mechanical movements at the molecular level.However,the investigations on their mechanical properties are lagging far behind their structural fabrication,especially for linear polyrotaxanes in bulk.Herein,we report stretchable poly[2]rotaxane elastomers(PREs)which integrate numerous mechanical bonds in the polymeric backbone to boost macroscopic mechanical properties.Specifically,we have synthesized a hydroxyfunctionalized[2]rotaxane that subsequently participates in the condensation polymerization with diisocyanate to form PREs.Benefitting from the peculiar structural and dynamic characteristics of the poly[2]rotaxane,the representative PRE exhibits favorable mechanical performance in terms of stretchability(∼1200%),Young’s modulus(24.6 MPa),and toughness(49.5 MJ/m^(3)).Moreover,we present our poly[2]rotaxanes as model systems to understand the relationship between mechanical bonds and macroscopic mechanical properties.It is concluded that the mechanical properties of our PREs are mainly determined by the unique topological architectures which possess a consecutive energy dissipation pathway including the dissociation of host−vip interaction and consequential sliding motion of the wheel along the axle in the[2]rotaxane motif.
