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工程科学与技术:2017,49(Z1):207-212
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合金元素Cu对α-Al2O3体结构拉伸强度和断裂性能影响的第一性原理研究
(四川大学 制造科学与工程学院)
Investigation of the Tensile Strength and Fracture Property of α-Al2O3Doped by Cu Ion Bulk-materials from First Principles
(School of Manufacturing Sci. and Eng.,Sichuan Univ.)
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投稿时间:2016-08-30    修订日期:2016-12-14
中文摘要: 随着粉末冶金技术的发展,金属粉末被广泛用于金属-氧化铝基陶瓷复合材料的制备,具有提高烧结活性、增强增韧的作用。为了从原子尺度研究金属元素对氧化铝陶瓷结构的力学性能影响,采用基于密度泛函理论的第一性原理计算手段,建立合金元素Cu替代α-Al2O3中Al3+的掺杂晶胞模型与纯净α-Al2O3晶胞模型,通过第一性原理计算模拟拉伸试验方法(FPCTT)研究二者的拉伸变形过程与断裂机制,该方法能够模拟晶胞沿单轴方向的理想拉伸变形过程。借助电荷密度分布图及差分图、Mulliken电荷布居分析等方法,从原子构型与电子结构方面研究合金元素Cu对陶瓷材料α-Al2O3的影响作用与机理。研究发现:纯净α-Al2O3晶胞在应变为0.18时达到理论拉伸强度(55.51 GPa),并且伴随着Al原子向邻近的O原子层弛豫,具有明显的屈服效应。在合金元素掺杂模型中,由于Cu与O较弱的键合作用,变形过程伴随着Cu—O键的衰弱断裂,杂质体系在应变为0.12时发生断裂,拉伸强度为40.33 GPa,其断裂方式为脆性断裂。结果表明:纯净的α-Al2O3结构单向拉伸变形过程伴随着较弱Al—O键的断裂且Al原子向O原子层弛豫,合金元素Cu进入基体结构后形成了键能更弱的Cu—O键,并在单向拉伸变形过程中率先断裂,导致体结构的断裂。说明合金元素Cu以原子替代方式进入α-Al2O3体结构中弱化了体结构的粘附性能,导致整体结构拉伸强度的降低。
中文关键词: Al2O3  第一性原理  拉伸强度  电子结构
Abstract:With the development of powder metallurgy technology,metallic powder has been widely used in the preparation of metal-alumina-based ceramic composites.Metal plays an important role in enhancing sintering activity,strengthening and toughening.In order to study the effect of metallic elements on the mechanical properties of alumina ceramics from the atomic scale, the first-principles calculation method based on density functional theory (DFT) was adopted.A typically ductile metal,Cu,substituted Al3+ of Al2O3 mixed structure cell model and pure Al2O3cell model were established,respectively.And the tensile strength and fractural properties of these two models were investigated via the first principle calculations tensile test (FPCTT),which could be applied to simulate the ideal tensile deformation of crystal along uniaxial direction.The effect of Cu on the Al2O3 was elucidated based on the analysis of charge density distribution and its difference,and the Mulliken charge population,etc.,from the electronic structure and mechanical properties of the systems.The results showed that the ideal tensile strength of pure Al2O3 crystal was 55.51 GPa with a critical strain of 18%.Moreover,the mode of fracture was plastic deformation,with obvious yield-effect,due to the gradual movement of Al atoms approaching to neighboring O atoms layers during the stretching process.The tensile strength of the doped system was 40.33 GPa with the corresponding strain of 12%.And the doping structure exhibited brittle fracture with the relatively weaker strength of Cu—O bond compared to that of Al—O.Consequently,the alloying Cu forms a weaker Cu—O bond which broke preferentially during the uniaxial tensile deformation process,leading to the fracture of bulk structure.The effect of alloying Cu will weaken the binding strength of bulk materials and further decrease the tensile strength of Al2O3.
文章编号:201600874     中图分类号:    文献标志码:
基金项目:国家自然科学基金资助项目(51275322;51575369)
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引用文本:
魏灿,尹德强,杨刚,刘剑,杨屹.合金元素Cu对α-Al2O3体结构拉伸强度和断裂性能影响的第一性原理研究[J].工程科学与技术,2017,49(Z1):207-212.
Wei Can,Yin Deqiang,Yang Gang,Liu Jian,Yang Yi.Investigation of the Tensile Strength and Fracture Property of α-Al2O3Doped by Cu Ion Bulk-materials from First Principles[J].Advanced Engineering Sciences,2017,49(Z1):207-212.