弹性应变能对沉淀组织及原子占位影响的微观相场模拟  

Microscopic phase field modeling on the influence of elastic strain energy on the precipitate microstructure and atomic site occupancy

作　　者：张静[1,2] 陈铮[1,2] 王永欣[1,2] 童立甲 

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

出　　处：《中国科技论文》2015年第16期1894-1899,共6页China Sciencepaper

基　　金：高等学校博士学科点专项科研基金资助项目(20136102120021);中央高校基本科研业务费专项资金资助项目(3102014JCQ01024);凝固技术国家重点实验室自主研究课题资助项目(114-QP-2014)

摘　　要：利用时间相关的微观相场法模拟弹性应变作用下Ni75AlxV25-x合金Ni3Al和Ni3V共格沉淀取向排列组织演化,明晰应变能对取向排列组织形貌的影响,追踪Ni3Al和Ni3V沉淀相形核、长大过程的原子占位解析取向排列的微观原子特征。计算结果表明:应变能阻碍形核,改变沉淀相Ni3Al和Ni3V的析出序列,诱发原子取向扩散形成取向排列组织;取向排列组织受温度和合金成分影响,低温下2相取向不明显,温度较高时,取向排列倾向加强。Al成分较低时,取向排列明显;Al成分增加,取向排列倾向弱化。原子占位的时间演化曲线定量表征了沉淀相析出全过程Ni、Al、V 3种组元在有序沉淀相Ni3Al和Ni3V的亚晶格位置的占位随时间演化,应变能推迟了Ni3Al相VNi、NiAl、VAl原子占位达到平衡的时间,但对NiNi和AlNi的占位达到平衡的时间并无大的影响。应变能抑制了Ni3V相反位缺陷VNiⅡ、NiV和第3组元占位AlNiⅠ、AlNiⅡ、AlV,诱发了反位缺陷VNiⅠ。A time dependent microscopic phase field model was applied to simulate the temporal evolution of directional arrange-ment microstructures caused by coherent Ni3 Al and Ni3 V precipitates in Ni75 Alx V25-x alloy upon the action of elastic strain energy. The influence of elastic strain energy on the directional arrangement microstructures and morphology was illustrated,and their atomic characteristics were demonstrated by tracing the atomic site occupancies during the nucleation and growth process of Ni3 Al and Ni3 V precipitates.The computational results indicate that the elastic strain energy hinders nucleation,changes the precipitate sequence of Ni3 Al and Ni3 V phase,and induces the directional diffusion of components forming directional arrangement micro-structure,which shows temperature and composition correlation.The directional arrangement is not evident at relatively low tem-perature or high Al content;however,atelevated temperature or low Al content,the directional arrangement becomes obvious. The temporal evolution of atomic site occupancy with time quantitatively characterizes the evolution of site occupancy for Ni,Al, and V components at the sublattices of both Ni3 Al and Ni3 V phases during the whole precipitation process.For Ni3 Al phase,the elastic strain energy impedes the atomic site occupancy of VNi ,NiAl ,VAl ,but has little effect on NiNi and AlNi .For Ni3 V phase, the elastic strain energy restrains the antisite defect of VNiI ,Niv and ternary alloying element AlNiI ,AlNiI ,Alv,but induces an-tisite defect VNiI .

关 键 词：组织演化 原子占位 共格沉淀组织 微观相场 微观组织表征 

分 类 号：TG113[金属学及工艺—物理冶金]