Atomic-scale computer simulation for early precipitation process of Ni75 Alx V25-x alloy with intermediate Al composition

作     者：ZHAO Yuhong 1*, JU Dongying 2, CHEN Zheng 3* and HOU Hua 1(1. College of Material Science & Engineering, China North University, Taiyuan 030051, China 2. Department of Mechanical Engineering, Saitama Institute of Technology, Okabe, Saitama 369 0239, Japan 3. Colledge of Materials Science & Engineering, Northwestern Polytechnical University, Xi'an 710072, China) 

作者机构：College of Material Science & Engineering China North University Taiyuan 030051 China Department of Mechanical Engineering Saitama Institute of Technology Okabe Saitama 369-0239 Japan Colledge of Materials Science & Engineering Northwestern Polytechnical University Xi' an 710072 China 

出 版 物：《Progress in Natural Science:Materials International》 (自然科学进展·国际材料(英文))

年 卷 期：2005年第4期

页      面：64-70页

学科分类：07[理学] 070203[理学-原子与分子物理] 0702[理学-物理学] 

基　　金：SupportedbytheNationalNaturalScienceFoundationofChina (GrantNo .5 0 0 710 46) 

主　　题：computer simulation early precipitation mechanism phase field model Ni75Alx V25-x alloy. 

摘      要：The microscopic phase field approach is applied to model the early precipitation process of Ni 75 Al x V 25- x alloy. Without any prior assumptions, this model can be used to simulate the temporal evolution of arbitrary morphologies and microstructures on atomic scale. By simulating the atomic pictures, and calculating the order parameters and volume fraction of the θ (Ni 3V) and γ′ (Ni 3Al) ordered phases, we study Ni 75 Al x V 25- x alloys with Al composition of 0.05, 0.053 and 0.055 (atom fraction). Our calculated results show that, for these alloys, θ and γ′ phases precipitate at the same time; with the increase of Al content, the amount of γ′ phase increases and that of θ phase decreases; the precipitation characteristic of γ′ phase transforms from Non Classical Nucleation and Growth (NCNG) to Congruent Ordering + Spinodal Decomposition (CO+SD) gradually; otherwise, the precipitation characteristic of θ phase transforms from Congruent Ordering + Spinodal Decomposition (CO+SD) to Non Classical Nucleation and Growth (NCNG) mechanism gradually. Both θ and γ′ phases have undergone the transition process of mixture precipitation mechanism characterized by both NCNG and CO+SD mechanisms. No incontinuous transition of precipitation mechanism has been found.