Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,...Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.展开更多
The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf ...The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.展开更多
Aggregation-induced emission(AIE)polymers have been extensively studied;however,the integration of AIE units into polyelectrolytes remains largely limited by the laborious multistep synthesis of pre-designed emissive ...Aggregation-induced emission(AIE)polymers have been extensively studied;however,the integration of AIE units into polyelectrolytes remains largely limited by the laborious multistep synthesis of pre-designed emissive monomers.Herein,we report a one-pot multicomponent polymerization method that directly produces main-chain charged polyelectrolytes with intrinsic AIE characteristics from non-emissive building blocks.By optimizing the monomer structures and reaction conditions,a series of soluble high-molecular-weight polymers with welldefined backbones were obtained in high yields.The resulting polyelectrolytes displayed robust AIE behavior,exhibiting fluorescence enhancement up to about 60-fold in an aqueous environment,and maintained excellent thermal stability.Owing to their cationic backbones,these polymers interact strongly with microbial surfaces and exhibit remarkable antimicrobial activities.This study establishes a synthetically efficient route to AIE polyelectrolytes and highlights their potential applications as multifunctional materials for bioimaging,antimicrobial therapy,and other applications.展开更多
This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,th...This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.展开更多
The complex interactions and conflicting performance demands in multi-component composites pose significant challenges for achieving balanced multi-property optimization through conventional trial-and-error approaches...The complex interactions and conflicting performance demands in multi-component composites pose significant challenges for achieving balanced multi-property optimization through conventional trial-and-error approaches.Machine learning(ML)offers a promising solution,markedly improving materials discovery efficiency.However,the high dimensionality of feature spaces in such systems has long impeded effective ML-driven feature representation and inverse design.To overcome this,we present an Intelligent Screening System(ISS)framework to accelerate the discovery of optimal formulations balancing four key properties in 15-component PTFE-based copper-clad laminate composites(PTFE-CCLCs).ISS adopts modular descriptors based on the physical information of component volume fractions,thereby simplifying the feature representation.By leveraging the inverse prediction capability of ML models and constructing a performance-driven virtual candidate database,ISS significantly reduced the computational complexity associated with high-dimensional spaces.Experimental validation confirmed that ISSoptimized formulations exhibited superior synergy,notably resolving the trade-off between thermal conductivity and peel strength,and outperform many commercial counterparts.Despite limited data and inherent process variability,ISS achieved an average prediction accuracy of 76.5%,with thermal conductivity predictions exceeding 90%,demonstrating robust reliability.This work provides an innovative,efficient strategy for multifunctional optimization and accelerated discovery in ultra-complex composite systems,highlighting the integration of ML and advanced materials design.展开更多
High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and co...High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and condensed matter physics due to their exceptional mechanical properties and unique high-entropy characteristic.Since the discovery of the first high-entropy superconductor in 2014,exploring their superconducting performance and advantages has progressively become a frontier in scientific research.The Ta-Nb-Hf-Zr-Ti system,in particular,exhibits remarkable mechanical robustness,outstanding radiation tolerance,and superconducting performance comparable to the binary NbTi alloy,positioning it as a promising candidate for advanced applications,such as high-field superconducting magnets,superconducting electric motors,and next-generation nuclear fusion reactors.This review systematically summarized global research progress on Ta-Nb-Hf-Zr-Ti-based superconductors,aiming to provide a comprehensive reference for advancing this burgeoning field.展开更多
Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their ...Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.展开更多
基金supported by the National Key R&D Pro-gram of China(Grant No.2021YFA0715803)the National Natural Science Foundation of China(Grant Nos.52293373,52130205,and 52302091)+1 种基金the Joint Fund of Henan Province Science and Technol-ogy R&D Program(No.225200810002)the ND Basic Research Funds of Northwestern Polytechnical University(No.G2022WD).
文摘Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.
基金National Key Research and Development Program of China(2021YFB3704103)National Natural Science Foundation of China(51571191)。
文摘The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.
基金supported by the National Natural Science Foundation of China(No.22431004)Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(No.2023B1212060003)。
文摘Aggregation-induced emission(AIE)polymers have been extensively studied;however,the integration of AIE units into polyelectrolytes remains largely limited by the laborious multistep synthesis of pre-designed emissive monomers.Herein,we report a one-pot multicomponent polymerization method that directly produces main-chain charged polyelectrolytes with intrinsic AIE characteristics from non-emissive building blocks.By optimizing the monomer structures and reaction conditions,a series of soluble high-molecular-weight polymers with welldefined backbones were obtained in high yields.The resulting polyelectrolytes displayed robust AIE behavior,exhibiting fluorescence enhancement up to about 60-fold in an aqueous environment,and maintained excellent thermal stability.Owing to their cationic backbones,these polymers interact strongly with microbial surfaces and exhibit remarkable antimicrobial activities.This study establishes a synthetically efficient route to AIE polyelectrolytes and highlights their potential applications as multifunctional materials for bioimaging,antimicrobial therapy,and other applications.
基金supported by the National Natural Science Foundation of China(No.U2330110)Youth Science Foundation Project(Category A)of Liaoning Province,China(No.2025JH6/101100006).
文摘This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.
基金financially supported by the National Key Research and Development Project of China(No.2022YFB3806900)。
文摘The complex interactions and conflicting performance demands in multi-component composites pose significant challenges for achieving balanced multi-property optimization through conventional trial-and-error approaches.Machine learning(ML)offers a promising solution,markedly improving materials discovery efficiency.However,the high dimensionality of feature spaces in such systems has long impeded effective ML-driven feature representation and inverse design.To overcome this,we present an Intelligent Screening System(ISS)framework to accelerate the discovery of optimal formulations balancing four key properties in 15-component PTFE-based copper-clad laminate composites(PTFE-CCLCs).ISS adopts modular descriptors based on the physical information of component volume fractions,thereby simplifying the feature representation.By leveraging the inverse prediction capability of ML models and constructing a performance-driven virtual candidate database,ISS significantly reduced the computational complexity associated with high-dimensional spaces.Experimental validation confirmed that ISSoptimized formulations exhibited superior synergy,notably resolving the trade-off between thermal conductivity and peel strength,and outperform many commercial counterparts.Despite limited data and inherent process variability,ISS achieved an average prediction accuracy of 76.5%,with thermal conductivity predictions exceeding 90%,demonstrating robust reliability.This work provides an innovative,efficient strategy for multifunctional optimization and accelerated discovery in ultra-complex composite systems,highlighting the integration of ML and advanced materials design.
基金Northwest Institute of Nonferrous Metal Research Funding(YK2324)Key Research and Development Program of Shaanxi(2024GX-YBXM-403)National Natural Science Foundation of China(52277029)。
文摘High-entropy alloys,a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices,have emerged as a research hotspot in materials science and condensed matter physics due to their exceptional mechanical properties and unique high-entropy characteristic.Since the discovery of the first high-entropy superconductor in 2014,exploring their superconducting performance and advantages has progressively become a frontier in scientific research.The Ta-Nb-Hf-Zr-Ti system,in particular,exhibits remarkable mechanical robustness,outstanding radiation tolerance,and superconducting performance comparable to the binary NbTi alloy,positioning it as a promising candidate for advanced applications,such as high-field superconducting magnets,superconducting electric motors,and next-generation nuclear fusion reactors.This review systematically summarized global research progress on Ta-Nb-Hf-Zr-Ti-based superconductors,aiming to provide a comprehensive reference for advancing this burgeoning field.
基金supported by the National Natural Science Foundation of China (Grant Nos.12334001,52461160301,52322311,52427802,12222414)the National Key R&D Program of China (Grant Nos.2024YFA1208201,2021YFA1400500,2021YFA1400204)the Youth Innovation Promotion Association of the CAS (Grant Nos.Y2022003 and 2020009)。
文摘Hafnia-based ferroelectrics have emerged as promising materials for next-generation nanoelectronics owing to their robust nanoscale properties and compatibility with metal-oxide-semiconductor technology.However,their metastable nature remains a key challenge for practical implementation.Utilizing scanning transmission electron microscopy,we investigated the atomic-scale mechanisms governing ferroelectric transitions and the metastability of polar phases in 10-nm-thick Hf_(0.5)Zr_(0.5)O_(2)thin films.Our results demonstrate that oxygen vacancies,coupled with rhombohedral distortions of the cation lattice,facilitate ferroelectric phase transitions and enable robust polar switching through adaptive processes,including cell-by-cell oxygen displacement and domain-wall-mediated nucleation and growth.These findings underscore the pivotal role of oxygen vacancies and lattice distortions in stabilizing polar phases and provide detailed insights into the atomic structures and transition dynamics of polymorphic Hf_(0.5)Zr_(0.5)O_(2-x),thereby advancing its potential for practical device applications.
