Finite-temperature ductility-brittleness and electronic structures of Al_(3)Sc,Al_(2)Sc and AlSc are studied comparatively by first-principles calculations and ab initio molecular dynamics.Results show that Al_(3)Sc a...Finite-temperature ductility-brittleness and electronic structures of Al_(3)Sc,Al_(2)Sc and AlSc are studied comparatively by first-principles calculations and ab initio molecular dynamics.Results show that Al_(3)Sc and Al_(2)Sc are brittle at both ground state and finite temperatures,while AlSc possesses a significantly superior ductility.At ground state,AlSc is ductile from Pugh's and Poisson's criteria,while it is brittle in Pettifor's model.The ductility of all Al_(3)Sc,Al_(2)Sc and AISc improves greatly with the elevated temperature.Especially,the Cauchy pressure of AlSc undergoes a transition from negative to positive.At T>600 K,AlSc is unequivocally classified as ductile from all criteria considered.In all compounds,the Al-Al bond originated from s-p and p-p orbital hybridizations,and the Al-Sc bond dominated by p-d covalent hybridization,are the first and second strongest chemical bonds,respectively.To explain the difference in mechanical properties,the mean bond strength(MBS)is introduced in this work.The weaker Al-Al bond in AlSc,leading to a smaller MBS,could be the origin of the softer elastic stiffness and superior intrinsic ductility.The longer length of the Al-Al bond in AlSc is responsible for its weaker bond strength.Furthermore,the enhanced metallicity of the Al-Al bond in AlSc would also contribute to its exceptional ductility.The longer length of the Al-Al bond in AISc is responsible for its weaker bond strength.Furthermore,the enhanced metallicity of the Al-Al bond in AlSc would also contribute to its exceptional ductility.展开更多
Aluminum-doped zinc oxide （ZnO：Al）, abbreviated as ZAO, is a novel and widely used transparent conductive material. The ZAO powder was synthesized by chemical coprecipitation. The ZAO ceramic sputtering target mate...Aluminum-doped zinc oxide （ZnO：Al）, abbreviated as ZAO, is a novel and widely used transparent conductive material. The ZAO powder was synthesized by chemical coprecipitation. The ZAO ceramic sputtering target materials were fabricated by sintering in air, and ZAO transparent conductive films were prepared by RF magnetron sputtering on glass substrates. XRD proved that such films had an orientation of （002） crystal panel paralleled to the surface of the glass substrate. The average transmittance of the films in the visible region exceeded 80%.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFB3504401)。
文摘Finite-temperature ductility-brittleness and electronic structures of Al_(3)Sc,Al_(2)Sc and AlSc are studied comparatively by first-principles calculations and ab initio molecular dynamics.Results show that Al_(3)Sc and Al_(2)Sc are brittle at both ground state and finite temperatures,while AlSc possesses a significantly superior ductility.At ground state,AlSc is ductile from Pugh's and Poisson's criteria,while it is brittle in Pettifor's model.The ductility of all Al_(3)Sc,Al_(2)Sc and AISc improves greatly with the elevated temperature.Especially,the Cauchy pressure of AlSc undergoes a transition from negative to positive.At T>600 K,AlSc is unequivocally classified as ductile from all criteria considered.In all compounds,the Al-Al bond originated from s-p and p-p orbital hybridizations,and the Al-Sc bond dominated by p-d covalent hybridization,are the first and second strongest chemical bonds,respectively.To explain the difference in mechanical properties,the mean bond strength(MBS)is introduced in this work.The weaker Al-Al bond in AlSc,leading to a smaller MBS,could be the origin of the softer elastic stiffness and superior intrinsic ductility.The longer length of the Al-Al bond in AlSc is responsible for its weaker bond strength.Furthermore,the enhanced metallicity of the Al-Al bond in AlSc would also contribute to its exceptional ductility.The longer length of the Al-Al bond in AISc is responsible for its weaker bond strength.Furthermore,the enhanced metallicity of the Al-Al bond in AlSc would also contribute to its exceptional ductility.
文摘Aluminum-doped zinc oxide （ZnO：Al）, abbreviated as ZAO, is a novel and widely used transparent conductive material. The ZAO powder was synthesized by chemical coprecipitation. The ZAO ceramic sputtering target materials were fabricated by sintering in air, and ZAO transparent conductive films were prepared by RF magnetron sputtering on glass substrates. XRD proved that such films had an orientation of （002） crystal panel paralleled to the surface of the glass substrate. The average transmittance of the films in the visible region exceeded 80%.
