外场下失稳区合金沉淀机制的计算机研究  

Computer Simulation of the Mechanism of Ordered Precipitates of Al-Li Alloy in External Energy Filed

作　　者：王永欣[1] 陈铮[1] 刘兵[1] 马良[1] 唐丽英[1] 赵宇宏[1] 

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2005年第1期46-50,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助(50071046);863项目资助项目;西北工业大学青年科技创新基金资助项目

摘　　要：基于离散格点形式的微扩散方程(Langevin方程)和非平衡自由能函数,编制了引入原子间相互作用能变化的Al3Li(δ?)相沉淀原子层面计算机模拟程序。该程序包容亚稳区到失稳区的全部温度、成分范围,孕育期至粗化的全过程,可以处理与时间相关的过程问题。开展了不同原子间相互作用势下原子图像、序参数的计算机模拟,进而探讨了最近邻原子相互作用能(W1)对有序相沉淀的影响机制。探明过渡区合金先发生等成分有序化,后进行失稳分解;随W1的增大,有序相沉淀的孕育期缩短,单相有序畴数量增多,面积减小,合金达到最大有序化的时间早,所能达到的最大有序化程度大。W1值较大,会促进合金有序化和原子簇聚,阻碍无序相的形成。A atomic-scale computer simulation programs of delta' (Al3Li) based on the microscopic diffusion equation and non-equilibrium free energy were firstly worked out, which can be used to process the problem relating with time. The precipitation mechanism of delta' was investigated by simulating the atomic pictures and calculating the order parameters, etc., and the variation in precipitation mechanism with the nearest interchange interaction energy (W-1), particularly the precipitation behavior of 13.5at%Li in Al-Li alloys were interpreted for the first time. It is found that the ordering reaction take place before the atom cluster processing. With the W-1 increase, the precipitation incubation period of delta' is shortened, the range of ordered phase decrease, and the number of ordered phase increase. The ordering process and atom clustering is promoted and the formation of the disordered phase is blocked while the nearest interchange interaction energy increase with the increase of W-1, the time in which the ordering of the alloy is the most is moved up, and the ordering degree of the alloy is increased.

关 键 词：原子间相互作用势 沉淀 原子图像 序参数 计算机模拟 

分 类 号：TG131[一般工业技术—材料科学与工程]