Atomic mobilities and diffusivities in the fcc, L12 and B2 phases of the Ni-Al system
Atomic mobilities and diffusivities in the fcc, L12 and B2 phases of the Ni-Al system
复制标题
DOI：
10.3139/146.110428
复制
发表时间：
2010-12
影响因子：
0.8
通讯作者：
Lijun Zhang;Yong Du;Qing Chen;I. Steinbach;Bai-yun Huang
中科院分区：
文献类型：
--
作者：
Lijun Zhang;Yong Du;Qing Chen;I. Steinbach;Bai-yun Huang
用唯象模型描述了NiüAl合金γ（fcc）/γ <$（L12）和A2/B2相的扩散系数。本文提出了一种有效的优化γü相原子迁移率的策略，该策略综合考虑了均匀性范围和缺陷浓度。这样的策略的结果在一个显着减少的原子迁移率参数的数量进行评估的L12相。在NiüAl系统中测得的成分和温度依赖的扩散系数已被本迁移率描述很好地复制。对于L12相，全面的比较表明，较少的模型参数，目前获得的迁移率产生更好的拟合实验扩散系数，与以前的评估相比。流动性的描述进一步验证通过比较计算和测量的浓度分布的各种扩散对。首次精确描述了退火蒸气Al / γ电偶的Al成分随时间的变化规律。
Abstract A phenomenological model was utilized to describe diffusivities in the γ (fcc) /γü (L12) and A2/B2 phases of the NiüAl system. An effective strategy, which takes the homogeneity range and defect concentration into account, was developed in the present work to optimize the atomic mobilities of γü phase. Such a strategy results in a dramatic decrease in the number of atomic mobility parameters to be evaluated for the L12 phase. The measured composition- and temperature- dependent diffusivities in the NiüAl system have been well replicated by the present mobility descriptions. For the L12 phase, comprehensive comparisons show that with fewer model parameters the presently obtained mobilities yield a better fit to experimental diffusivities, compared with previous assessments. The mobility descriptions are further validated by comparing calculated and measured concentration profiles for various diffusion couples. The time-dependent Al composition profile for the annealed vapor Al / γ couple is accurately described for the first time.