First-principles calculations for the elastic properties of Ni-base model superalloys:Ni/Ni3Al multilayers

• 来源期刊: 中国物理B（英文版）
• 关键词: Ni-based superalloys Ni/NiaAl multilayer mechanical property first principles rule ofmixture
• 年，卷（期）: 2009,（10）
• 页码范围: 4339-4348
• 页数: 10页
• 语种: 英文

摘要

A model system consisting of Ni[001](100)/NiaAl[001](100)multi-layers are studied using the density functionaltheory in order to explore the elastic properties of single crystal Ni-based superalloys.Simulation results are consistentwith the experimental observation that rafted Ni-base superalloys virtually possess a cubic symmetry.The convergenceof the elastic properties with respect to the thickness of the multilayers are tested by a series of multilayers from 2γ+2γto 10γ+10γ atomic layers.The elastic properties axe found to vary little with the increase of the multilayer's thickness.A Ni/NiaAl multilayer with 10γ'+10γatomic layers(3.54 nm)can be used to simulate the mechanical properties ofNi-base model superalloys.Our calculated elastic constants,bulk modulus,orientation-dependent shear modulus andYoung's modulus.as well as the Zener anisotropy factor are all compatible with the measured results of Ni.base modelsuperalloys R1 and the advanced commercial superalloys TMS-26.CMSX-4 at a low temperature.The mechanicalproperties as a function of theγphase volume fraction are calculated by varying the proportion of theγ andγ'phasein the multilayers.Besides,the mechanical properties of two-phase Ni/Ni3A1 multilayer call be well predicted by theVoigt-Reuss-Hill rule of mixtures.