Abstract We present a new method based on uncorrelated misorientation measurements by Electron Backscattered Diffraction (EBSD) to characterize the dislocation density of site-specific areas selected on a bulk material. Gold samples submitted to different degrees of pre-straining are analyzed. A new scalar misorientation parameter called the Characteristic Misorientation Angle (CMA) is derived from uncorrelated misorientation data and compared to the more conventional parameters Grain Average Misorientation (GAM) and Grain Orientation Spread (GOS). We show that CMA is nearly independent of the scan step size and is more sensitive to plastic deformation than GAM and GOS. A coupled effect of local plastic strain and area size is observed on the measured values of CMA. Based on that, values of dislocation density are determined for site-specific areas whose strengths, as defined by the hardness at first pop-in, are subsequently measured by spherical nanoindentation. Results show that the site-specific strength of gold decreases with increasing initial dislocation density. While previous studies have suggested the same trend, the present work offers a new approach to more quantitatively correlate local dislocation densities to the onset of plasticity, without the need for destructive TEM investigations or micro-sample fabrication.

中文翻译：

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基于不相关取向角的新型应变指示器，用于将位错密度与局部强度相关联

摘要 我们提出了一种基于电子背散射衍射 (EBSD) 不相关取向差测量的新方法，以表征在块状材料上选择的位点特定区域的位错密度。分析了经过不同程度预应变的金样品。一个新的标量误定向参数称为特征误定向角 (CMA)，它是从不相关的误定向数据中导出的，并与更传统的参数颗粒平均误定向 (GAM) 和颗粒取向扩展 (GOS) 进行比较。我们表明 CMA 几乎与扫描步长无关，并且比 GAM 和 GOS 对塑性变形更敏感。在 CMA 的测量值上观察到局部塑性应变和面积大小的耦合效应。基于此，位错密度的值是针对特定位置的区域确定的，其强度由第一次弹出时的硬度定义，随后通过球形纳米压痕测量。结果表明，金的位点特异性强度随着初始位错密度的增加而降低。虽然之前的研究表明了相同的趋势，但目前的工作提供了一种新方法，可以更定量地将局部位错密度与可塑性的开始联系起来，而无需进行破坏性的 TEM 研究或微样品制造。