The structural, elastic, electronic and optical properties for U3Si2-type AlSc2Si2 compound under pressure were systematically investigated by using the first-principles calculations. The values of elastic constants a...The structural, elastic, electronic and optical properties for U3Si2-type AlSc2Si2 compound under pressure were systematically investigated by using the first-principles calculations. The values of elastic constants and elastic moduli indicate that AlSc2Si2 keeps mechanical stability under high pressure. The mechanical properties of AISc2Si2 are compared with those of Al3Sc. The results indicate that AlSc2Si2 is harder than AI3Sc. Anisotropic constant AU and 3D curved surface of elastic moduli predict that AISc2Si2 is obviously anisotropic under pressure. The electronic structure of AlSc2Si2 exhibits metallic character and the metallicity decreases with the elevated pressure. In addition, optical properties as a function of pressure were calculated and analyzed. The present work provides theoretical support for further experimental work and industrial applications.展开更多
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
基金Projects(L2014051,LT2014004)supported by the Program for Scientific Technology Plan of the Educational Department of Liaoning Province,China
文摘The structural, elastic, electronic and optical properties for U3Si2-type AlSc2Si2 compound under pressure were systematically investigated by using the first-principles calculations. The values of elastic constants and elastic moduli indicate that AlSc2Si2 keeps mechanical stability under high pressure. The mechanical properties of AISc2Si2 are compared with those of Al3Sc. The results indicate that AlSc2Si2 is harder than AI3Sc. Anisotropic constant AU and 3D curved surface of elastic moduli predict that AISc2Si2 is obviously anisotropic under pressure. The electronic structure of AlSc2Si2 exhibits metallic character and the metallicity decreases with the elevated pressure. In addition, optical properties as a function of pressure were calculated and analyzed. The present work provides theoretical support for further experimental work and industrial applications.
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.
