The digital image correlation (DIC) of speckle patterns obtained by vapour-assisted gold remodelling at 200 – 350 °C has already been used to map plastic strains with submicron resolution. However, it has not so far proved possible to use such patterns for testing at high temperatures. Here we demonstrate how a gold speckle pattern can be made that is stable at 700 °C, to study deformation in a commercial TiAl alloy (Ti-45Al-2Nb-2Mn(at%)-0.8 vol% TiB2). The pattern is made up of a uniformly sized random array of Au islands as small as 15 nm in diameter, depending on reconstruction parameters, with a sufficiently small spacing to be suitable for nano-scale, nDIC, strain mapping at a subset size of 60 × 60 nm2. It can be used at temperatures up to 700 °C for many hours, for high cycle fatigue testing for instance. There is good particle attachment to the substrate. It can withstand ultra-sound cleaning, is thermally stable and has a high atomic number contrast for topography-free backscatter electron imaging.

中文翻译：

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用于高达 700 °C 的纳米级应变映射的稳定散斑图案

在 200 – 350 °C 下通过蒸汽辅助金重塑获得的散斑图案的数字图像相关性 (DIC) 已用于绘制亚微米分辨率的塑性应变图。然而，到目前为止还没有证明可以使用这种模式在高温下进行测试。在这里，我们展示了如何制作在 700 °C 下稳定的金斑点图案，以研究商业 TiAl 合金（Ti-45Al-2Nb-2Mn(at%)-0.8 vol% TiB2）的变形。该图案由直径小至 15 nm 的均匀大小的 Au 岛随机阵列组成，具体取决于重建参数，具有足够小的间距以适用于纳米级、nDIC、子集大小为 60 的应变映射× 60 nm2。它可以在高达 700 °C 的温度下使用多个小时，例如用于高周疲劳测试。有良好的颗粒附着到基材上。它可以承受超声波清洗，热稳定并且具有高原子序数对比度，可用于无地形背散射电子成像。