Atomic-scale computer simulation for ternary alloy Ni-Cr-Al during early precipitation process  

作　　者：CHUZhong CHENZheng WANGYongxin LUYanli LIYongsheng 

机构地区：[1]StateKeyLaboratoryofSolidificationProcessing,NorthwesternPolytechnicalUniversity,Xi＇an710072,China [2]StateKeyLaboratoryofSolidificationProcessing,NorthwesternPolytechnicalUniversity,Xi＇an710072,China

出　　处：《Progress in Natural Science:Materials International》2005年第7期656-660,共5页自然科学进展·国际材料（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 50071046)

摘　　要：The aging behaviors of Ni-Cr-Al ternary alloy are studied at temperature 873 K based on the mean-field theory, and the early precipitation process is simulated at atomic-scale with microscopic phase-field model. The precipitation mechanism of the low supersaturated alloy Ni-12.2at. %Cr-7. 8at.% At is non-classical nucleation and growth, the L1(2) structure (Ni3Al) and D0(22) structure (Ni3Cr) phases precipitate simultaneously, a part of D0(22) phase transmits to L1(2) structure phase, and other part retains its previous structure. For high supersaturated alloy, congruent ordering appears first, then followed by spinodal decomposition, the nonstoicheometric ordered phases are produced in this process, which occurs before clustering. The precipitation mechanism of Ni-Sat. %Cr-18at. %Al alloy is similar to Ni-10at. %Cr-12at. %Al alloy, but the ordering process of the former is ahead of the latter.The aging behaviors of Ni-Cr-Al ternary alloy are studied at temperature 873 K based on the mean-field theory, and the early precipitation process is simulated at atomic-scale with microscopic phase-field model. The precipitation mechanism of the low supersaturated alloy Ni-12.2at. % Cr-7.8at. % Al is non-classical nucleation and growth, the L12 structure (Ni3Al) and D022 structure (Ni3Cr)phases precipitate simultaneously, a part of D022 phase transmits to L12 structure phase, and other part retains its previous structure. For high supersaturated alloy, congruent ordering appears first, then followed by spinodal decomposition, the nonstoicheometric ordered phases are produced in this process, which occurs before clustering. The precipitation mechanism of Ni-8at. % Cr-18at. %Al alloy is similar to Ni-10at. % Cr-12at. %Al alloy, but the ordering process of the former is ahead of the latter.

关 键 词：microscope phase-field model NI-CR-AL PRECIPITATION ordering parameter SIMULATION 

分 类 号：TP391.9[自动化与计算机技术—计算机应用技术]