杂质Cu对α-AlO的拉伸变形与断裂性能影响-工程科学与技术.DOCVIP

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 魏 灿，尹德强，杨 刚，刘 剑，杨 屹* （四川大学 制造科学与工程学院，四川 成都 610065） 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，第一性原理计算模拟拉伸试验方法（FPCTT）研究了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Mulliken电荷布居分析，从原子与电子结构方面研究了合金元素Cu对陶瓷材料α-Al2O3的影响作用与机理。发现：纯净α-Al2O3晶胞在应变为0.18时达到理论拉伸强度（55.51GPa），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40.33GPa，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，而合金元素Cu的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。 关键字：Al2O3陶瓷；第一性原理；拉伸强度；电子结构 中图分类号：TF124 文献标志码： Investigation of the Tensile Strength and Fracture Property of α-Al2O3 Doped by Cu Ion Bulk-materials from First Principles WEI Can, YIN Deqiang, YANG Gang, LIU Jian, YANG Yi* (School of manufacturing Sci. and Eng. , Sichuan Univ. , Chengdu 610065, China) Abstract: With the development of powder metallurgy technology, metallic powder was 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 Al2O3 cell 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 Mulli