Kolli R Prakash, Seidman David N
Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208-3108, USA.
Microsc Microanal. 2007 Aug;13(4):272-84. doi: 10.1017/S1431927607070675.
A multicomponent Fe-Cu based steel is studied using atom-probe tomography. The precipitates are identified using two different methodologies and subsequent morphological and compositional results are compared. The precipitates are first identified using a maximum separation distance algorithm, the envelope method, and then by a concentration threshold method, an isoconcentration surface. We discuss in detail the proper selection of the parameters needed to delineate precipitates utilizing both methods. The results of the two methods exhibit a difference of 44 identified precipitates, which can be attributed to differences in the basis of both methods and the sensitivity of our results to user-prescribed parameters. The morphology of the precipitates, characterized by four different precipitate radii and precipitate size distribution functions (PSDs), are compared and evaluated. A variation of less than approximately 8% is found between the different radii. Two types of concentration profiles are compared, giving qualitatively similar results. Both profiles show Cu-rich precipitates containing Fe with elevated concentrations of Ni, Al, and Mn near the heterophase interfaces. There are, however, quantitative disagreements due to differences in the basic foundations of the two analysis methods.
采用原子探针层析技术对一种多组分铁铜基钢进行了研究。使用两种不同方法识别析出相，并比较随后得到的形态和成分结果。首先使用最大分离距离算法（包络法）识别析出相，然后通过浓度阈值法（等浓度面）识别。我们详细讨论了使用这两种方法描绘析出相所需参数的恰当选择。两种方法的结果显示，识别出的析出相数量相差44个，这可归因于两种方法的基础差异以及我们的结果对用户规定参数的敏感性。比较并评估了以四种不同析出相半径和析出相尺寸分布函数（PSD）表征的析出相形态。发现不同半径之间的变化小于约8%。比较了两种类型的浓度分布，得到定性相似的结果。两种分布均显示富铜析出相中含有铁，在异相界面附近镍、铝和锰的浓度升高。然而，由于两种分析方法的基本原理不同，存在定量差异。
