Abstract The orientation, hardness and Young's modulus of Al3Yb single crystal were analyzed using the electron back scatter diffraction (EBSD) and nanoindentation techniques, combined with the first principles calculations. The Al3Yb single crystal of about 1 mm size could be obtained by heating hypereutectic Al-38.5 (wt%)Yb alloy to liquid state and cooling to room temperature at 60 °C/h. The results showed that the hardnesses of the Al3Yb single crystals oriented in (318), (023), (213), (112) and (122) directions varied between 5.4 ± 0.1 and 5.7 ± 0.1 GPa, and the reduced modulus were between 131.9 ± 1.6 and 140.5 ± 3.9 GPa. First principles calculations by assuming standard Yb pseudopotential with 4f electrons showed that the elastic constants of C11, C12 and C44 were 149.4, 32.94 and 66.59 GPa, respectively, and the Poisson's ratio was 0.161. Based on these calculated elastic constants and Poisson's ratio and the reduced modulus values, the Young's modulus of the Al3Yb single crystal was determined to be between 148.4 ± 2.3 and 154.9 ± 2.3 GPa for different orientations and the anisotropy coefficient (A) was 1.17 ± 0.01.

中文翻译：

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纳米压痕研究Al3Yb单晶的硬度和杨氏模量

摘要 采用电子背散射衍射(EBSD)和纳米压痕技术，结合第一性原理计算，对Al3Yb单晶的取向、硬度和杨氏模量进行了分析。通过将过共晶 Al-38.5 (wt%) Yb 合金加热至液态并以 60 °C/h 的速度冷却至室温，可以获得尺寸约为 1 mm 的 Al3Yb 单晶。结果表明，取向在（318）、（023）、（213）、（112）和（122）方向的Al3Yb单晶的硬度在5.4±0.1和5.7±0.1GPa之间变化，降低的模量在131.9 ± 1.6 和 140.5 ± 3.9 GPa。假设标准 Yb 赝势与 4f 电子的第一性原理计算表明，C11、C12 和 C44 的弹性常数分别为 149.4、32.94 和 66.59 GPa，泊松' s比率为0.161。基于这些计算出的弹性常数和泊松比以及降低的模量值，Al3Yb 单晶的杨氏模量被确定为不同取向的 148.4 ± 2.3 和 154.9 ± 2.3 GPa 之间，各向异性系数 (A) 为 1.17 ± 0.01 .