Effect of the continuous stiffness measurement on the mechanical properties extracted using spherical nanoindentation
Effect of the continuous stiffness measurement on the mechanical properties extracted using spherical nanoindentation
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DOI：
10.1016/j.actamat.2013.03.005
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发表时间：
2013-06-01
期刊：
影响因子：
9.4
通讯作者：
Kalidindi, S. R.
中科院分区：
文献类型：
--
作者：
Vachhani, S. J.;Doherty, R. D.;Kalidindi, S. R.
采用1微米和100微米半径的探头对不同样品进行了球形纳米压痕试验，系统地研究了连续刚度测量(CSM)技术中叠加振动载荷对压痕应力应变(ISS)曲线的影响。特别注意对载荷、位移和刚度信号所需的校正，以说明叠加振荡的影响。振动频率从通常使用的45赫兹降低会导致测量的刚度值降低。这导致了ISS曲线中有问题的高应变硬化值。当使用1 nm的振荡幅度时，记录的刚度信号中的噪声水平显著更高。得出的结论是，这些观测是机器动态控制系统的产物，并不代表材料的真实行为。振荡频率为45 Hz、幅值为2 nm的CMS信号产生最合理的刚度值，因此是可靠提取所研究材料ISS曲线的最佳选择。(C)2013 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
The effects of the superimposed oscillating load while using the continuous stiffness measurement (CSM) technique on the extracted indentation stress strain (ISS) curves were systematically investigated using spherical nanoindentation tests performed on a variety of samples, using probes of 1 and 100 mu m radii. Particular care was afforded to the corrections that were needed on the load, displacement and stiffness signals to account for the effect of the superimposed oscillations. A decrease in the oscillation frequency from the commonly used 45 Hz caused the measured stiffness values to decrease. This resulted in questionable high strain hardening values in the ISS curves. The noise levels in the recorded stiffness signal were significantly higher while using an oscillation amplitude of 1 nm. It was concluded that these observations are artifacts of the machine dynamic control systems and do not represent the material's true behavior. The CMS signal with a 45 Hz oscillation frequency and 2 nm amplitude appears to produce most reasonable values of stiffness values and is therefore the best choice for reliably extracting ISS curves for the materials studied. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.