Abstract The accurate determination of mechanical parameters (namely, Young's modulus and hardness) of shale-constitutive minerals is crucial for predicting the macroscale mechanical parameters of shale composites. This study employed an advanced nanoindentation apparatus equipped with a high-resolution microscope (4000×) and a newly emerging nano-dynamic mechanical analysis (nano-DMA) module to conduct mineral-positioned indentation and investigate the depth profiles of mechanical parameters of shale matrix minerals, with the objective of obtaining their intrinsic mechanical values. To conduct mineral-positioned nanoindentation, various matrix minerals were pre-discerned under the optical microscope based on their particle shapes, surface features, and reflection colors. The mechanical response curves show that silicates (quartz and feldspar) exhibit significant elastic characteristics, whereas carbonates (dolomite and calcite) and clay minerals exhibit a combined deformation behavior of elasticity and plasticity based on the elastic recovery ratio and plastic work ratio. The mechanical depth profiles produced by nano-DMA show that the mechanical parameters of all aforementioned minerals decrease rapidly with respective to the increase in indentation depth, before reaching stable values. This variation pattern for the mechanical parameters is a result of the indentation size effect (ISE), which comes from the internal structure (or texture) adjustment of the indented material in small deformed volumes during indenter invasion. Whereas the platform section represents the indenter overcoming the ISE layer and actually probing the material as it is, the mechanical values measured at this stage can be recognized as the true values for the indented materials. In addition, the tested mineral grains would be easily affected by the substrate phases at a much larger indentation depth, and the mechanical parameters would correspondingly change in the mechanical depth profiles after the plateau stage. Overall, our findings identify reliable Young's moduli and hardnesses for different matrix minerals: 30 GPa and 1.5 GPa for clay minerals, 105–110 GPa and 14–16 GPa for quartz, 75–85 GPa and 9–10 GPa for feldspar, 70–75 GPa and 2–3 GPa for calcite, and 115–120 GPa and 7–8 GPa for dolomite.

中文翻译：

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使用相定位纳米压痕和纳米动态力学分析对页岩基质矿物进行力学表征

摘要 准确测定页岩组成矿物力学参数（即杨氏模量和硬度）对于预测页岩复合材料宏观力学参数至关重要。本研究采用配备高分辨率显微镜（4000×）和新兴纳米动态力学分析（nano-DMA）模块的先进纳米压​​痕仪进行矿物定位压痕并研究页岩基质力学参数的深度剖面矿物，目的是获得它们的内在机械值。为了进行矿物定位纳米压痕，在光学显微镜下根据其颗粒形状、表面特征和反射颜色对各种基质矿物进行预判别。力学响应曲线表明，硅酸盐（石英和长石）表现出显着的弹性特征，而碳酸盐（白云石和方解石）和粘土矿物表现出基于弹性恢复比和塑性功比的弹性和塑性组合变形行为。纳米 DMA 产生的机械深度剖面表明，所有上述矿物的机械参数随着压痕深度的增加而迅速下降，然后达到稳定值。机械参数的这种变化模式是压痕尺寸效应 (ISE) 的结果，它来自压头侵入过程中小变形体积内压痕材料的内部结构（或纹理）调整。虽然平台部分代表压头克服 ISE 层并按原样实际探测材料，但在此阶段测量的机械值可以识别为压痕材料的真实值。此外，被测矿物颗粒在更大的压痕深度处很容易受到基体相的影响，并且在平台阶段之后力学参数会相应地在力学深度剖面中发生变化。总体而言，我们的研究结果确定了不同基质矿物的可靠杨氏模量和硬度：粘土矿物为 30 GPa 和 1.5 GPa，石英为 105-110 GPa 和 14-16 GPa，长石为 75-85 GPa 和 9-10 GPa，70-方解石为 75 GPa 和 2-3 GPa，白云石为 115-120 GPa 和 7-8 GPa。在这个阶段测量的机械值可以被认为是压痕材料的真实值。此外，被测矿物颗粒在更大的压痕深度处很容易受到基体相的影响，并且在平台阶段之后力学参数会相应地在力学深度剖面中发生变化。总体而言，我们的研究结果确定了不同基质矿物的可靠杨氏模量和硬度：粘土矿物为 30 GPa 和 1.5 GPa，石英为 105-110 GPa 和 14-16 GPa，长石为 75-85 GPa 和 9-10 GPa，70-方解石为 75 GPa 和 2-3 GPa，白云石为 115-120 GPa 和 7-8 GPa。在这个阶段测量的机械值可以被认为是压痕材料的真实值。此外，被测矿物颗粒在更大的压痕深度处很容易受到基体相的影响，并且在平台阶段之后力学参数会相应地在力学深度剖面中发生变化。总体而言，我们的研究结果确定了不同基质矿物的可靠杨氏模量和硬度：粘土矿物为 30 GPa 和 1.5 GPa，石英为 105-110 GPa 和 14-16 GPa，长石为 75-85 GPa 和 9-10 GPa，70-方解石为 75 GPa 和 2-3 GPa，白云石为 115-120 GPa 和 7-8 GPa。并且在高原阶段之后，力学参数会在力学深度剖面中发生相应的变化。总体而言，我们的研究结果确定了不同基质矿物的可靠杨氏模量和硬度：粘土矿物为 30 GPa 和 1.5 GPa，石英为 105-110 GPa 和 14-16 GPa，长石为 75-85 GPa 和 9-10 GPa，70-方解石为 75 GPa 和 2-3 GPa，白云石为 115-120 GPa 和 7-8 GPa。并且在高原阶段之后，力学参数会在力学深度剖面中发生相应的变化。总体而言，我们的研究结果确定了不同基质矿物的可靠杨氏模量和硬度：粘土矿物为 30 GPa 和 1.5 GPa，石英为 105-110 GPa 和 14-16 GPa，长石为 75-85 GPa 和 9-10 GPa，70-方解石为 75 GPa 和 2-3 GPa，白云石为 115-120 GPa 和 7-8 GPa。