A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5w...A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5wt%Er-1wt%TiB_(2)/Al-Mn-Mg-Sc-Zr nanocomposite were prepared using vacuum homogenization technique,and the density of samples prepared through the LPBF process reached 99.8%.The strengthening and toughening mechanisms of Er-TiB_(2)were investigated.The results show that Al_(3)Er diffraction peaks are detected by X-ray diffraction analysis,and texture strength decreases according to electron backscatter diffraction results.The added Er and TiB_(2)nano-reinforcing phases act as heterogeneous nucleation sites during the LPBF forming process,hindering grain growth and effectively refining the grains.After incorporating the Er-TiB_(2)dual-phase nano-reinforcing phases,the tensile strength and elongation at break of the LPBF-deposited samples reach 550 MPa and 18.7%,which are 13.4%and 26.4%higher than those of the matrix material,respectively.展开更多
Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled t...Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.展开更多
The age-hardening response,mechanical,and corrosion-resistant properties of AA7085 alloys with and without the addition of 0.3 wt.%scandium(Sc)were compared.Using advanced techniques such as aberration-corrected trans...The age-hardening response,mechanical,and corrosion-resistant properties of AA7085 alloys with and without the addition of 0.3 wt.%scandium(Sc)were compared.Using advanced techniques such as aberration-corrected transmission electron microscopy and first-principles calculations,the underlying micromechanisms of Sc microalloying were revealed.Results show that the increase in strength of the AA7085-Sc alloy is mainly attributed to the decreased Al grain size and increased number density of both Al_(3)Sc@Al_(3)(Sc,Zr)core−shell nanoparticles and Sc-containingη_(p) and GP−η_(p) nanoprecipitates.Strong strain fields and evident electron transfer from Zr to the neighboring matrix Al atoms exist at the Al_(3)Sc@Al_(3)(Sc,Zr)/Al interface.The Sc doping in GP−η_(p) andη_(p) suppresses the GP−η_(p)→η_(p) transformation.Modified corrosion resistance of the AA7085-Sc alloy compared with AA7085 alloy is associated with the fine grain boundary precipitates ofη_(p)hases and narrow precipitation free zone.The reasons of property changes of AA7085 alloy after Sc microalloying are explored based on the multiscale microstructural characterization.展开更多
The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynam...The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynamics(MD)simulations,and other analytical techniques.The precipitation behavior during different aging stages of the supersaturated solid solution formed after rapid cold punching was focused,which induces rapid dissolution of precipitates.The findings reveal that the precipitation sequence is significantly influenced by aging temperature.At higher aging temperatures,which mitigate lattice distortion in the matrix,the precipitation sequence follows the conventional path.Conversely,at lower aging temperatures,where lattice distortion persists,the sequence deviates,suppressing the formation of Guinier−Preston−Bagaryatsky(GPB)zones.MD simulations confirm that the variations in solute atom diffusion rates at different aging temperatures lead to the differences in the S'phase precipitation sequence.展开更多
The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behavior...The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.展开更多
This review provides a comprehensive overview of recent advancements in aluminum-based conductor alloys engineered to achieve superior mechanical strength and thermal stability without sacrificing electrical conductiv...This review provides a comprehensive overview of recent advancements in aluminum-based conductor alloys engineered to achieve superior mechanical strength and thermal stability without sacrificing electrical conductivity.Particular emphasis is placed on the role of microalloying elements—particularly Sc and Zr-in promoting the formation of coherent nanoscale precipitates such as Al_(3)Zr,Al_(3)Sc,and core-shell Al_(3)(Sc,Zr)with metastable L1_(2)crystal structures.These precipitates contribute significantly to high-temperature performance by enabling precipitation strengthening and stabilizing grain boundaries.The review also explores the emerging role of other rare earth elements(REEs),such as erbium(Er),in accelerating precipitation kinetics and improving thermal stability by retarding coarsening.Additionally,recent advancements in thermomechanical processing strategies are examined,with a focus on scalable approaches to optimize the strength-conductivity balance.These approaches involve multi-step heat treatments and carefully controlled manufacturing sequences,particularly the combination of cold drawing and aging treatment to promote uniform and effective precipitation.This review offers valuable insights to guide the development of cost-effective,high-strength,heat-resistant aluminum alloys beyond conductor applications,particularly those strengthened through microalloying with Sc and Zr.展开更多
基金Shaanxi Province Qin Chuangyuan“Scientist+Engineer”Team Construction Project(2022KXJ-071)2022 Qin Chuangyuan Achievement Transformation Incubation Capacity Improvement Project(2022JH-ZHFHTS-0012)+8 种基金Shaanxi Province Key Research and Development Plan-“Two Chains”Integration Key Project-Qin Chuangyuan General Window Industrial Cluster Project(2023QCY-LL-02)Xixian New Area Science and Technology Plan(2022-YXYJ-003,2022-XXCY-010)2024 Scientific Research Project of Shaanxi National Defense Industry Vocational and Technical College(Gfy24-07)Shaanxi Vocational and Technical Education Association 2024 Vocational Education Teaching Reform Research Topic(2024SZX354)National Natural Science Foundation of China(U24A20115)2024 Shaanxi Provincial Education Department Service Local Special Scientific Research Program Project-Industrialization Cultivation Project(24JC005,24JC063)Shaanxi Province“14th Five-Year Plan”Education Science Plan,2024 Project(SGH24Y3181)National Key Research and Development Program of China(2023YFB4606400)Longmen Laboratory Frontier Exploration Topics Project(LMQYTSKT003)。
文摘A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5wt%Er-1wt%TiB_(2)/Al-Mn-Mg-Sc-Zr nanocomposite were prepared using vacuum homogenization technique,and the density of samples prepared through the LPBF process reached 99.8%.The strengthening and toughening mechanisms of Er-TiB_(2)were investigated.The results show that Al_(3)Er diffraction peaks are detected by X-ray diffraction analysis,and texture strength decreases according to electron backscatter diffraction results.The added Er and TiB_(2)nano-reinforcing phases act as heterogeneous nucleation sites during the LPBF forming process,hindering grain growth and effectively refining the grains.After incorporating the Er-TiB_(2)dual-phase nano-reinforcing phases,the tensile strength and elongation at break of the LPBF-deposited samples reach 550 MPa and 18.7%,which are 13.4%and 26.4%higher than those of the matrix material,respectively.
基金supported by the Research Project on Strengthening the Construction of an Important Ecological Security Barrier in Northern China by Higher Education Institutions in the Inner Mongolia Autonomous Region(STAQZX202313)the Inner Mongolia Autonomous Region Education Science‘14th Five-Year Plan’2024 Annual Research Project(NGJGH2024635).
文摘Vacancy defects,as fundamental disruptions in metallic lattices,play an important role in shaping the mechanical and electronic properties of aluminum crystals.However,the influence of vacancy position under coupled thermomechanical fields remains insufficiently understood.In this study,transmission and scanning electron microscopy were employed to observe dislocation structures and grain boundary heterogeneities in processed aluminum alloys,suggesting stress concentrations and microstructural inhomogeneities associated with vacancy accumulation.To complement these observations,first-principles calculations and molecular dynamics simulations were conducted for seven single-vacancy configurations in face-centered cubic aluminum.The stress response,total energy,density of states(DOS),and differential charge density were examined under varying compressive strain(ε=0–0.1)and temperature(0–600 K).The results indicate that face-centered vacancies tend to reduce mechanical strength and perturb electronic states near the Fermi level,whereas corner and edge vacancies appear to have weaker effects.Elevated temperatures may partially restore electronic uniformity through thermal excitation.Overall,these findings suggest that vacancy position exerts a critical but position-dependent influence on coupled structure-property relationships,offering theoretical insights and preliminary experimental support for defect-engineered aluminum alloy design.
基金the support from the National Natural Science Foundation of China (Nos. U20A20274, 52061003)the Natural Science Foundation of Yunnan Province, China (No. 202301AT070209)the Science and Technology Major Project of Yunnan Province, China (No. 202102AG050017)。
文摘The age-hardening response,mechanical,and corrosion-resistant properties of AA7085 alloys with and without the addition of 0.3 wt.%scandium(Sc)were compared.Using advanced techniques such as aberration-corrected transmission electron microscopy and first-principles calculations,the underlying micromechanisms of Sc microalloying were revealed.Results show that the increase in strength of the AA7085-Sc alloy is mainly attributed to the decreased Al grain size and increased number density of both Al_(3)Sc@Al_(3)(Sc,Zr)core−shell nanoparticles and Sc-containingη_(p) and GP−η_(p) nanoprecipitates.Strong strain fields and evident electron transfer from Zr to the neighboring matrix Al atoms exist at the Al_(3)Sc@Al_(3)(Sc,Zr)/Al interface.The Sc doping in GP−η_(p) andη_(p) suppresses the GP−η_(p)→η_(p) transformation.Modified corrosion resistance of the AA7085-Sc alloy compared with AA7085 alloy is associated with the fine grain boundary precipitates ofη_(p)hases and narrow precipitation free zone.The reasons of property changes of AA7085 alloy after Sc microalloying are explored based on the multiscale microstructural characterization.
基金supported by the China Scholarship Council (CSC) Local Cooperation Program (No. 202308430176)the National Natural Science Foundation of China (No. 52271177)the Hunan Provincial Natural Science Foundation Regional Joint Fund, China (No. 2023JJ50173)。
文摘The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynamics(MD)simulations,and other analytical techniques.The precipitation behavior during different aging stages of the supersaturated solid solution formed after rapid cold punching was focused,which induces rapid dissolution of precipitates.The findings reveal that the precipitation sequence is significantly influenced by aging temperature.At higher aging temperatures,which mitigate lattice distortion in the matrix,the precipitation sequence follows the conventional path.Conversely,at lower aging temperatures,where lattice distortion persists,the sequence deviates,suppressing the formation of Guinier−Preston−Bagaryatsky(GPB)zones.MD simulations confirm that the variations in solute atom diffusion rates at different aging temperatures lead to the differences in the S'phase precipitation sequence.
基金financially supported by the National Key Research and Development Program of China (No. 2019YFA0708801)the National Natural Science Foundation of China (No. 51875125)。
文摘The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.
文摘This review provides a comprehensive overview of recent advancements in aluminum-based conductor alloys engineered to achieve superior mechanical strength and thermal stability without sacrificing electrical conductivity.Particular emphasis is placed on the role of microalloying elements—particularly Sc and Zr-in promoting the formation of coherent nanoscale precipitates such as Al_(3)Zr,Al_(3)Sc,and core-shell Al_(3)(Sc,Zr)with metastable L1_(2)crystal structures.These precipitates contribute significantly to high-temperature performance by enabling precipitation strengthening and stabilizing grain boundaries.The review also explores the emerging role of other rare earth elements(REEs),such as erbium(Er),in accelerating precipitation kinetics and improving thermal stability by retarding coarsening.Additionally,recent advancements in thermomechanical processing strategies are examined,with a focus on scalable approaches to optimize the strength-conductivity balance.These approaches involve multi-step heat treatments and carefully controlled manufacturing sequences,particularly the combination of cold drawing and aging treatment to promote uniform and effective precipitation.This review offers valuable insights to guide the development of cost-effective,high-strength,heat-resistant aluminum alloys beyond conductor applications,particularly those strengthened through microalloying with Sc and Zr.
