Microscopic phase-field study on directional coarsening mechanism caused by interaction between precipitates in Ni-Al-V alloy  

微观相场法研究镍基合金沉淀相间作用的定向粗化机制(英文)

作　　者：杨坤[1] 陈铮[1] 王永欣[1] 范晓丽[1] 

机构地区：[1]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》2013年第1期193-200,共8页中国有色金属学报（英文版）

基　　金：Projects(51075335,10902086,50875217) supported by the National Natural Science Foundation of China;Project(JC201005) supported by the Northwestern Polytechnical University Foundation for Fundamental Research,China;Project(CX201007) supported by the Doctorate Foundation of Northwestern Polytechnical University,China

摘　　要：A microscopic phase-field model was used to investigate a directional coarsening mechanism caused by the anisotropic growth of long period stacking and different effects of phases on precipitation in Ni-Al-V alloy.The results show that DO22 mainly coarsens along its short axis,which may press the neighboring L12,leading to the interaction among atoms.Diffusion channels of Al are formed in the direction where the mismatch between γ＇ and γ reduces;the occupation probabilities are anisotropic in space;and direction coarsening of L12 occurs finally.With a rise of ageing temperature,phases appear later and DO22 is much later at a higher temperature,the average occupation probabilities of Al and V reduce,and Al changes more than V.采用微观相场法研究Ni-Al-V合金中由长周期沉淀相各向异性生长所引起的定向粗化机制以及沉淀过程对有序相的不同作用。结果表明:DO22相主要沿着其短轴方向粗化,挤压相邻的L12相并导致原子间的相互作用,使其与基体间的错配发生变化,并在特定方向上释放出配错能,形成Al原子的扩散通道,引起其原子占位在空间上的各向异性,最终导致L12相定向粗化。随着时效温度的升高,两相的析出滞后,而DO22相在较高温度的滞后更为显著;Al和V的平均占位几率降低,且Al降低得较多。

关 键 词：nickel-based alloys microscopic phase-field simulation directional coarsening anisotropic growth MISMATCH diffusion 

分 类 号：TG146.15[一般工业技术—材料科学与工程]