Dual-phase high-entropy alloys containing facecentered cubic(fcc) and body-centered cubic(bcc) phases achieve a combination of high strength and high ductility,which attract extensive attention.Compared with singlepha...Dual-phase high-entropy alloys containing facecentered cubic(fcc) and body-centered cubic(bcc) phases achieve a combination of high strength and high ductility,which attract extensive attention.Compared with singlephase high-entropy alloys,the dual-phase structure generates more complex deformation mechanisms such as structural transformation and interactions between grain boundaries and dislocations during deformation.In order to understand the structural transformation of the dual-phase high-entropy alloy during deformation and its effect on mechanical properties,Al_(0.5)CoCrNiFe high-entropy alloy was prepared and its deformation mechanism was investigated by molecular dynamics simulations combined with experiments.The results show that phase transformation occurred during deformation,and dislocation slip was the main deformation mechanism.In addition,there was significant dislocation pile-up at the interface between fcc and bcc phases after tensile deformation.Temperatures and strain rates significantly affected the mechanical properties and deformation behavior of high-entropy alloys.At low temperature and high strain rate,the dislocation density of the alloy increases after stretching,resulting in the enhancement of tensile strength.展开更多
This study investigated the effect of 0.25 wt%Sc addition on the microstructure and mechanical properties of AA 7055 alloy.The addition of Sc obviously refined the grains of AA 7055 alloy during casting,homogenizing,r...This study investigated the effect of 0.25 wt%Sc addition on the microstructure and mechanical properties of AA 7055 alloy.The addition of Sc obviously refined the grains of AA 7055 alloy during casting,homogenizing,rolling,solution,and aging treatments due to the formation of primary and precipitate Al3(Sc,Zr)phase.The recrystallization and precipitation of AA 7055 alloy were inhibited during heat treatments by Sc addition.The Sccontaining AA 7055 alloy exhibited higher thermal stability than AA 7055 alloy during homogenizing treatment,because of the grain boundary pinning effect of nano-sized Al3(Sc,Zr)particles.Given its structure characteristics such as fine grains,fineη′phase,and lessηphase,AA 7055 alloy with added Sc showed good mechanical properties after aging at 120℃for 24 h,with an ultimate tensile strength(UTS)of 679 MPa and elongation(EL)of 14%.This work provides an effective strategy to fabricate AlZn-Mg(-Cu)series(7 xxx)alloys with excellent mechanical properties.展开更多
基金sponsored by the National Key R&D Program of China (No.2018YFC1902401)the National Natural Science Foundation of China(No.52005053)Open Fund of Key Laboratory of New Processing Technology for Nonferrous Metal & Materials Ministry of Education,China (No.20KF-24)。
基金financially supported by the National Natural Science Foundation of China (Nos.92166105 and 52005053)the High-Tech Industry Science and TechnologyInnovation Leading Program of Hunan Province (No.2020GK2085)+1 种基金the Science and Technology Innovation Program of Hunan Province (No.2021RC3096)the Open Fund of Key Laboratory of New Processing Technology for Nonferrous Metal & Materials Ministry of Education (No.20KF-24)。
文摘Dual-phase high-entropy alloys containing facecentered cubic(fcc) and body-centered cubic(bcc) phases achieve a combination of high strength and high ductility,which attract extensive attention.Compared with singlephase high-entropy alloys,the dual-phase structure generates more complex deformation mechanisms such as structural transformation and interactions between grain boundaries and dislocations during deformation.In order to understand the structural transformation of the dual-phase high-entropy alloy during deformation and its effect on mechanical properties,Al_(0.5)CoCrNiFe high-entropy alloy was prepared and its deformation mechanism was investigated by molecular dynamics simulations combined with experiments.The results show that phase transformation occurred during deformation,and dislocation slip was the main deformation mechanism.In addition,there was significant dislocation pile-up at the interface between fcc and bcc phases after tensile deformation.Temperatures and strain rates significantly affected the mechanical properties and deformation behavior of high-entropy alloys.At low temperature and high strain rate,the dislocation density of the alloy increases after stretching,resulting in the enhancement of tensile strength.
基金financially supported by the National Natural Science Foundation of China(No.51601045)the Research Program of Science and Technology of Guangxi(No.GKAB16380021)the Guangxi“Bagui”Teams for Innovation and Research。
文摘This study investigated the effect of 0.25 wt%Sc addition on the microstructure and mechanical properties of AA 7055 alloy.The addition of Sc obviously refined the grains of AA 7055 alloy during casting,homogenizing,rolling,solution,and aging treatments due to the formation of primary and precipitate Al3(Sc,Zr)phase.The recrystallization and precipitation of AA 7055 alloy were inhibited during heat treatments by Sc addition.The Sccontaining AA 7055 alloy exhibited higher thermal stability than AA 7055 alloy during homogenizing treatment,because of the grain boundary pinning effect of nano-sized Al3(Sc,Zr)particles.Given its structure characteristics such as fine grains,fineη′phase,and lessηphase,AA 7055 alloy with added Sc showed good mechanical properties after aging at 120℃for 24 h,with an ultimate tensile strength(UTS)of 679 MPa and elongation(EL)of 14%.This work provides an effective strategy to fabricate AlZn-Mg(-Cu)series(7 xxx)alloys with excellent mechanical properties.
