What is it about?
A nano-indenter is a tool to provide compression load to a material of interest to determine its mechanical properties such as modulus, hardness, and friction at the micro or nanometer scale. A nano-indenter device can be combined with a Scanning Electron Microscope (SEM) to implement an in situ imaging technique that can enable direct observation of mechanical behaviors of nanoscale materials . Thus, fast and efficient in situ nanoindentation tests can provide new insights into the mechanical behaviors of materials in nanometer regimes. The fine positioners or positioning stages and coarse positioners or positioning stages currently available for in situ nanoindentation devices inside the SEMs are considered large in size and have complex mechanisms.
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Why is it important?
Taking the avails of flexure mechanisms , actuator units of positioners provide high-precision motion at the micro or nanometer scale . Small volumes of the SEM chambers demand further development and miniaturization of the in situ nanoindentation devices. Besides, some nanoindentation techniques require a large stroke or displacement range of the indenter device, specifically the fine positioner. For example, the Continuous Stiffness Measurement (CSM) technique is used to evaluate elastic properties as a function of continuous penetration depth without the need for discrete unloading cycles. This technique can be very useful to better characterize the beam-like deflection or the foam-like buckling of Vertically Aligned Carbon Nanotube (VACNT) arrays having a height range of 500-1500 µm. However, the maximum stroke or displacement range of the existing high-precision actuators (driven units) is typically 10 µm - 40 µm.
Perspectives
The objective of this work is to develop a new design concept of a compact, high precision driven unit for an in situ nanoindentation device capable of long stroke (up to 1 mm) along the indentation axis with nano-newton force and nanometer displacement resolutions. This can be used to realize axial penetration of an intender tool to a tall specimen or a large number of samples assembled together, with relative ease and high-frequency loading and unloading cycles. The miniaturized driven unit can be easily integrated into the small working area of an SEM chamber for direct observation. Such a new device can facilitate a better understanding of the mechanical properties or behaviors of nanoscale materials with large-length scale structures and various morphologies.
Richard (Ricky) Smith Jr.
Read the Original
This page is a summary of: Designing a Compact High-precision Positioner with Large Stroke Capability for Nanoindentation Devices, November 2023, IgMin Publications Inc.,
DOI: 10.61927/igmin118.
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