Payne Matthew A, Miller James B, Gellman Andrew J
Carnegie Mellon University , Department of Chemical Engineering, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
Carnegie Mellon University , W.E. Scott Institute for Energy Innovation, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
ACS Comb Sci. 2016 Sep 12;18(9):559-68. doi: 10.1021/acscombsci.6b00047. Epub 2016 Aug 2.
Composition spread alloy films (CSAFs) are commonly used as libraries for high-throughput screening of composition-property relationships in multicomponent materials science. Because lateral gradients afford two degrees of freedom, an n-component CSAF can, in principle, contain any composition range falling on a continuous two-dimensional surface through an (n - 1)-dimensional composition space. However, depending on the complexity of the CSAF gradients, characterizing and graphically representing this composition range may not be straightforward when n ≥ 4. The standard approach for combinatorial studies performed using quaternary or higher-order CSAFs has been to use fixed stoichiometric ratios of one or more components to force the composition range to fall on some well-defined plane in the composition space. In this work, we explore the synthesis of quaternary Al-Fe-Ni-Cr CSAFs with a rotatable shadow mask CSAF deposition tool, in which none of the component ratios are fixed. On the basis of the unique gradient geometry produced by the tool, we show that the continuous quaternary composition range of the CSAF can be rigorously represented using a set of two-dimensional "pseudoternary" composition diagrams. We then perform a case study of (AlxFeyNi1-x-y)∼0.8Cr∼0.2 oxidation in dry air at 427 °C to demonstrate how such CSAFs can be used to screen an alloy property across a continuous two-dimensional subspace of a quaternary composition space. We identify a continuous boundary through the (AlxFeyNi1-x-y)∼0.8Cr∼0.2 subspace at which the oxygen uptake into the CSAF between 1 and 16 h oxidation time increases abruptly with decreasing Al content. The results are compared to a previous study of the oxidation of AlxFeyNi1-x-y CSAFs in dry air at 427 °C.
成分分布合金薄膜（CSAFs）通常用作多组分材料科学中高通量筛选成分-性能关系的库。由于横向梯度提供了两个自由度，原则上，一个n组分的CSAF可以包含通过（n - 1）维成分空间落在连续二维表面上的任何成分范围。然而，根据CSAF梯度的复杂性，当n≥4时，表征和以图形方式表示这个成分范围可能并不简单。使用四元或更高阶CSAF进行组合研究的标准方法是使用一种或多种组分的固定化学计量比，以使成分范围落在成分空间中的某个明确界定的平面上。在这项工作中，我们使用可旋转荫罩CSAF沉积工具探索四元Al-Fe-Ni-Cr CSAFs的合成，其中没有一个组分比例是固定的。基于该工具产生的独特梯度几何形状，我们表明CSAF的连续四元成分范围可以使用一组二维“伪三元”成分图进行严格表示。然后，我们对（AlxFeyNi1-x-y）∼0.8Cr∼0.2在427°C干燥空气中的氧化进行了案例研究，以证明这种CSAFs可用于在四元成分空间的连续二维子空间中筛选合金性能。我们确定了一条穿过（AlxFeyNi1-x-y）∼0.8Cr∼0.2子空间的连续边界，在该边界处，氧化1至十六小时期间进入CSAF的氧吸收量随着Al含量的降低而突然增加。将结果与之前关于AlxFeyNi1-x-y CSAFs在427°C干燥空气中氧化的研究进行了比较。
