Effects of Sample Mounting on Hardness and Modulus Measured Through Instrumented Indentation

Many unaccounted factors or issues can be encountered while performing or preparing for nanoindentation that result in erroneous data. Some issues, such as improper sample surface preparation or sample surface pile-up, have been well documented in the literature with many potential solutions and recommendations, but others have received much less attention. One such issue is sample mounting, which has significant influence on the overall compliance of the nanoindentation system and can result in a large amount of error in hardness and modulus measurements. For the worst mounting conditions tested in this dataset, the hardness was measured to be approximately 11% off from the target value and the modulus was 9% off from the target value. Therefore, to better understand the effect of different mounting conditions, nearly identical fused silica samples were mounted using 11 common mounting methods and then tested with nanoindentation using the same conditions and parameters. The results show how certain mounting conditions can introduce more compliance into the system and thus produce inaccurate data in terms of both the measured hardness and modulus of the material.在开展纳米压痕（nanoindentation）测试或筹备测试流程时，诸多未被充分考量的因素与问题都可能导致实验数据出现偏差。其中部分问题，如样品表面制备不当或样品表面压痕隆起，已有大量文献详实记载并给出诸多可行的解决方案与建议，但其余多数问题则鲜有学者关注。样品装卡（sample mounting）便是此类受关注不足的问题之一：它会对纳米压痕系统的整体柔度产生显著影响，进而导致硬度与模量测量结果出现大幅误差。在本数据集所测试的最差装卡条件下，测得的硬度值与目标值偏差约11%，模量值与目标值偏差约9%。因此，为更深入地探究不同装卡条件的影响，研究人员采用11种常见装卡方法对近乎一致的熔融石英（fused silica）样品进行装卡，并在完全相同的测试条件与参数下开展纳米压痕测试。测试结果表明，特定装卡条件会为系统引入额外柔度，从而使得材料的硬度与模量测量数据出现偏差。