An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstru...An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstruc- rural investigations, hierarchical nanotwinned lamellar AISc bundles with embedded micron-/submicron-sized AI2Sc and AISc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of -1.85 GPa to- gether with pronounced work hardening and a large plasticity of -14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AISc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of mierocracks formed by local stress transition.展开更多
AlScN piezoelectric films prepared by AlSc alloy sputter targets are essential materials for 5G radio frequency filters.The thermophysical properties of AlSc alloy targets are closely related to their welding processe...AlScN piezoelectric films prepared by AlSc alloy sputter targets are essential materials for 5G radio frequency filters.The thermophysical properties of AlSc alloy targets are closely related to their welding processes and applications.Al-xSc alloys(x=5,10,15,20,25,at%)were prepared by vacuum induction melting,whose purity is mainly determined by the raw materials and the production process.The results reveal that as the Sc content increases from 5at%to 20at%,the volume fraction of the Al_(3)Sc phase in the alloy increases from 26.9%to 80.2%,and the average grain size of the Al_(3)Sc phase increases from 12.9μm to 67.7μm during this period.Additionally,both the coefficient of thermal expansion(CTE)and thermal conductivity(TC)of AlSc alloys exhibit a downward trend.Based on experimental data and first-principles calculations,the effective medium theory and the Turner model effectively predict the TC and CTE of Al-xSc alloys.The optimal characteristic parameter(k0)of the Turner model is determined to be 50.The model predictions align well with the experimental results.展开更多
基金Supported by the Scientific Research Foundation of Xi’an University of Technology under Grant No 101-451115007the National Basic Research Program of China under Grant No 2007CB613900+1 种基金the National Natural Science Foundation of China under Grant No 51174161the Pivot Innovation Team of Shaanxi Electric Materials and Infiltration Technique under Grant No 2012KCT-25
文摘An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstruc- rural investigations, hierarchical nanotwinned lamellar AISc bundles with embedded micron-/submicron-sized AI2Sc and AISc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of -1.85 GPa to- gether with pronounced work hardening and a large plasticity of -14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AISc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of mierocracks formed by local stress transition.
基金National Key Research and Development Program of China(2022YFB3504402,2023YFB3610101)。
文摘AlScN piezoelectric films prepared by AlSc alloy sputter targets are essential materials for 5G radio frequency filters.The thermophysical properties of AlSc alloy targets are closely related to their welding processes and applications.Al-xSc alloys(x=5,10,15,20,25,at%)were prepared by vacuum induction melting,whose purity is mainly determined by the raw materials and the production process.The results reveal that as the Sc content increases from 5at%to 20at%,the volume fraction of the Al_(3)Sc phase in the alloy increases from 26.9%to 80.2%,and the average grain size of the Al_(3)Sc phase increases from 12.9μm to 67.7μm during this period.Additionally,both the coefficient of thermal expansion(CTE)and thermal conductivity(TC)of AlSc alloys exhibit a downward trend.Based on experimental data and first-principles calculations,the effective medium theory and the Turner model effectively predict the TC and CTE of Al-xSc alloys.The optimal characteristic parameter(k0)of the Turner model is determined to be 50.The model predictions align well with the experimental results.
