Finite-temperature ductility-brittleness and electronic structures of Al_(n)Sc(n=1,2 and 3)  

作　　者：Xue-Qian Wang Ying Zhao Hao-Xuan Liu Shu-Chen Sun Hong-Bo Yang Jia-Min Zhong Gan-Feng Tu Song Li Yu-Dong Zhang Claude Esling Hai-Le Yan Liang Zuo 

机构地区：[1]Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education),School of Material Science and Engineering,Northeastern University,Shenyang 110819,China [2]School of Metallurgy,Northeastern University,Shenyang 110819,China [3]Rare Earth Functional Materials(Xiong'an)Innovation Center Co.,Ltd.Xiong'an 071700,China [4]Laboratoire d'étude des Microstructures et de Mécanique des Matériaux(LEM3),Unikersitéde Lorraine,57045Metz,France

出　　处：《Rare Metals》2024年第8期3974-3989,共16页稀有金属（英文版）

基　　金：financially supported by the National Key R&D Program of China(No.2022YFB3504401)。

摘　　要：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.

关 键 词：Al-Sc Target materials Intrinsic ductility Finite-temperature elastic constant First-principles calculation 

分 类 号：TG146.21[一般工业技术—材料科学与工程]