Simulation of pre-precipitation in Ni_(75)Al_(14)Mo_(11) alloy by microscopic phase-field model  

Ni_(75)Al(14)Mo_(11)合金早期沉淀过程的微观相场法模拟（英文）

作　　者：梁晶晶[1] 李瑞琴[1] 赵耀红[1] 

机构地区：[1]中北大学机械与动力工程学院,太原030051

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第7期2361-2366,共6页中国有色金属学报（英文版）

基　　金：Project(51275486)supported by the National Natural Science Foundation of China

摘　　要：The early precipitation process of Ni（75）Al（14）Mo（11） alloy was simulated by microscopic phase-field model at different temperatures.The microstructure of the alloy,the precipitation time of Llo structure and occupation probability of the three kinds of atoms were investigated.It is indicated that the non-stoichiometric Ll0（Ⅰ/Ⅱ） phases are found in the precipitation process.With the temperature increasing,the appearance time of Ll0 is brought forward.The Ll0（Ⅱ） structure always precipitates earlier than the Ll0（Ⅰ） structure.Compared with lower temperature,higher temperature brings the formation time of Ll0 phase forward and makes Ll0 phase have a higher order degree.But lower temperature shortens the process time of the Ll0 phase to the Ll2 phase.Al and Mo atoms tend to occupy γ site,Ni atom tends to occupy a and β sites.At the same temperature,Al atom has stronger occupation ability than Mo atom in the same site.Ni,Al and Mo collectively form the composited Ll2 structure.采用微观相场动力学模型研究不同温度下Ni_(75)Al_(14)Mo_(11)合金的早期沉淀过程,研究合金的微观结构、Ll_0相的析出时间以及3种原子的占位概率。结果表明:沉淀过程中析出Ll_0非化学计量比有序相,Ll_0相有Ⅰ型和Ⅱ型2种结构,随着温度的增加,Ll_0相析出的时间提前。在沉淀的过程,Ⅱ型Ll_0结构的析出时间比Ⅰ型Ll_0结构的析出时间早。温度升高缩短了Ll_0相的形成时间,使Ll0相有序度更高;温度越低,Ll_0相向L1_2相的转变时间越短。Al原子和Mo原子占据γ位,Ni原子占据α位和β位,在同样的温度和格点下,Al原子的占位几率大于Mo原子的占位几率。Ni、Al和Mo_3种原子构成复合Ll_2相。

关 键 词：Ni75Al（14）M0（11） alloy microscopic phase-field model precipitation incubation period Ll0（Ⅰ/Ⅱ） phase 

分 类 号：TG146.15[一般工业技术—材料科学与工程]