Ageing process of pre-precipitation phase in Ni_(0.75)Al_(0.05)Fe_(0.2) alloy based on phase field method  

基于相场法的Ni_(0.75)Al_(0.05)Fe_(0.2)合金预析出相时效过程(英文)

作　　者：董卫平[1] 王永欣[1] 陈铮[1,2] 杨坤[1] 

机构地区：[1]西北工业大学材料学院,西安710072 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《Transactions of Nonferrous Metals Society of China》2011年第5期1105-1111,共7页中国有色金属学报（英文版）

基　　金：Projects(10902086, 50941020, 50875217) supported by the National Natural Science Foundation of China; Projects(JC201005) supported by Basic Research Fund of Northwestern Polytechnical University, China; Project supported by Graduate Starting Seed Fund and Doctoral Foundation of Northwestern Polytechnical University, China

摘　　要：By utilizing phase field method combined with analysis on free energy and interatomic potentials, pre-precipitation phase formation and transformation process of Ni0.75Al0.05Fe0.2 alloy in early precipitation stage during the ageing process under 1 000 K were studied. And free energy, microstructures, compositions and volume fractions of pre-precipitation phase and equilibrium phase were analyzed. The simulation results indicate that nonstoichiometric Llo pre-precipitation phase formed first, and then would gradually transform into L12 equilibrium phase. It is discovered that the phase transformation process was closely related to free energy and interatomic potentials. Additionally, it is revealed that free energy of Llo pre-precipitation phase was higher and interatomic potential was smaller than that of L12 equilibrium phase. Therefore, it is concluded that Llo phase was unstable, and phase transformation would occur to L12 which was more stable.用微观相场法结合自由能和原子间作用势研究了Ni0.75Al0.05Fe0.2合金在1000K时效中沉淀前期的预析出相的形成和转变过程;分析了沉淀前期预析出相和平衡相的自由能、微结构、成分和相体积分数随时间的变化。研究表明:由于结构接近,原子有序化首先形成非化学计量比预析出相L10,随着时间的延长,预析出相L10逐渐向L12相转变,并逐渐达到化学计量比平衡相L12。且发现此转变过程与自由能和原子间作用势有关,预析出相L10比平衡相L12的自由能高且原子间作用势小,故L10相不稳定且转变为稳定的L12相。

关 键 词：pre-precipitation phase equilibrium phase interatomic potentials free energy phase field method 

分 类 号：TG111.5[金属学及工艺—物理冶金]