2-8. Recent progress in phase-composition map determination by thin film combinatorial chip method

Lanting Zhang, Jian Hui, Bingbing Zhao, Yuanxun Zhou, Cai Chen, Xiaodong Xiang, Hong Wang 

1. Shanghai Jiao Tong University, 2. Southern University of Science and Technology

Abstract:The high-throughput experimentation is one of the three supporting conerstones and key technologies of the Materials Genome Engineering (MGE) programme. Combined with high-throughput preparation methods, high-throughput characterization of structure and composition is the basis for rapidly constructing structure-composition-performance relationships. The main ideas of the overall framework have been published in 2015. Following these ideas, this paper reports the progress in the rapid construction of phase diagrams using combinatorial thin-film material chips, including the homogenization heat treatment, the pixel-by-pixel laser heat treatment, and the high-throughput characterization using microbeam X-ray diffraction and fluorescence.

      Combinatorial materials chips were prepared by ion beam sputtering with a continuous moving mask. High throughput structure and chemical characterization of the chips was carried out using microbeam X-ray from synchrotron radiation source and two-dimensional detector. The typical single-point characterization time was between 1 and 6 s, and up to 2,000 data points were characterized on a single chip. The rapid construction of the phase distribution in the component space was achieved by automatically classifying the X-ray patterns using hierarchical clustering algorithm.

      First of all, taking the Fe-Co-Ni system as a typical case, 100 nm thick combinatorial materials chips covering the entire Fe-Co-Ni ternary composition range were subjected to isothermal crystallization treatment at 500, 600, 700°C followed by quenching. Microbeam XRD and XRF were performed on a synchrotron radiation beamline, and the data were classified by hierarchical clustering algorithm. The resulting ternary component-structure distribution maps were consistent with the isothermal sections of the corresponding ASM alloy phase diagrams. Thus, rapid construction of the phase-composition map (phase diagram) in the ternary system is preliminarily realized.

       Then, taking the Ni-Ti-Cu system as an example, the compostion dependent diffusion induced amorphization transformation of the multilayer film was studied. In the entire composition space of the Ni-Ti-Cu ternary system, a Cu-Ti-Ni-Ti stack was used to prepare a composite chip with a total thickness of 80 nm, which underwent low-temperature annealing at 373K for 110 h. High-throughput characterization was carried out at synchrotron radiation beamline. The resulting amorphous phase distribution maps of in the as-deposited state and after low-temperature diffusion are consistent with that acquired by co-sputtering method reported by Ruhr University in 2012. This indicates that the method can be used to construct a "phase diagram" of amorphous transformation.

      Finally, taking the Cu-Cr-Co ternary system as an example, the phase distribution of the ternary component with immiscible systems was studied. Composite chips with a total thickness of 100 nm covering the entire composition space of the Cu-Cr-Co ternary system were prepared based on single-cycle stacking and 10-cycle stacking, respectively. The chips were isothermally treated at 700 and 800°C for 2 h in vacuum and then quenched to room temperature. Under the same processing conditions, a high-temperature stable structure was introduced due to the kinetic effect in the 10-cycle stacked chip compared with the single-cycle stacked chip. The phase distribution of the 10-cycle stacked chip after 800°C/2 h treatment is similar to the thermodynamically calculated isothermal section at 1027°C, even though there is a certain gap from the heat treatment temperature.

      Based on the above three cases, the relevant thermodynamic and kinetic effects on the rapid construction of phase diagrams using thin-film combinatorial materials chips are further discussed. Keywords : Combinatorial materials chip; synchrotron radiation, phase diagram; diffusion; amorphization

      薄膜组合材料芯片技术构建相图研究新进展

张澜庭，惠健，赵冰冰，周元勋，陈才，项晓东，汪洪
1. 上海交通大学;2. 南方科技大学 

摘要:快速构建材料成分-结构-工艺-性能间关系的高通量实验技术是“材料基因工程”(MGE) 三大支撑平台和关键技术之一，与高通量制备技术相结合，高通量的结构和成分表征是构建结构-成分-性能关系的基础。本文的部分作者于 2015 年在 Engineering 杂志上撰文提出了主要想法， 沿着这一思路，本文报道利用薄膜组合材料芯片结合均匀化热处理、激光逐点热处理与微束 X 射线衍射及荧光高通量表征，在快速构建相图方面的研究进展。 采用离子束溅射结合连续移动掩模制备组合材料芯片样品;利用同步辐射光源亮度高的优势， 并采用二维探测器，单点表征时间在 1~6 s 间，单芯片样品上表征数据点最高达到 2000 点;使 用基于机器学习分级聚类分析算法对数据进行自动归类，实现了快速构建成分空间中的相分布。

      首先以 Fe-Co-Ni 系统为典型案例，将 100nm 厚的覆盖 Fe-Co-Ni 三元系成分范围的组合材 料芯片，在 500、600、700oC 进行等温晶化处理后快速冷却至室温，通过在同步辐射实验线站 上微束 X 射线 XRD+XRF 联合表征，利用机器学习算法对数据进行分类处理，所绘制的三元成 分-结构分布图与 ASM 相应的三元相图等温截面吻合，初步实现了快速构建成分空间中的相分 布(相图)。

      其次以 Ni-Ti-Cu 系统为例，研究了多层膜低温扩散非晶转化与成分的关系。在 Ni-Ti-Cu 三 元系全成分空间内，按 10 nm 为一个周期，采用 Cu-Ti-Ni-Ti 的堆垛顺序，制备了总厚度为 80 nm 的组合材料芯片，经 373K/110 h 低温扩散，在同步辐射线站进行高通量表征，获得 Ni-Ti-Cu 三 元系中制备态和低温扩散态的非晶转变分布图，与德国鲁尔大学 2012 年所报道的利用共溅射方 法所测定的相图一致，证明本方法可以用于构建非晶转化“相图”。

       最后以 Cu-Cr-Co 三元系为例，研究了具有不互溶体系的三元成分空间中等温处理后的相分 布问题。分别按单周期堆垛和 10 周期堆垛的方式制备了覆盖 Cu-Cr-Co 三元系全成分空间的总 膜厚为 100 nm 的组合材料芯片样品，分别在真空中经 700 和 800°C等温处理 2 h 后快速冷却至 室温。结果表明，在相同处理条件下，与单周期堆垛的芯片相比，在 10 周期堆垛的样品中，由 于扩散动力学的因素，引入了高温稳定的结构。10 周期堆垛的样品经 800°C/2 h 处理后的相分 布更加接近于热力学计算的 1027°C等温截面，与 800°C下的等温截面有一定差距。

      基于以上三个案例，进一步讨论相关热力学和动力学参数对利用薄膜组合材料芯片快速构建相图的影响规律。

关键词:组合材料芯片;同步辐射;相图;扩散，非晶化