Using Nano-Impact to Optimize Properties of Thin Films, Coatings and Bulk Materials

By AZoNano Editors

Table of Contents

Introduction
History of Nano-Impact
The Principle of Nano-Impact
Probe Acceleration Impact for Low Cycle Fatigue
Sample Oscillation Impact for High Cycle Fatigue
Conclusions
About Micro Materials

Introduction

The study of fatigue and fracture processes is possible by allowing repeated contact through impact. It is possible to sense the onset of damage as an “in situ” wear test and acquire mechanistic information that can be much more advantageous in intelligent coating design than simply reporting an average wear rate or hardness.

History of Nano-Impact

Nano-Impact was developed and has been patented by Micro Materials according to EU Patent 1095254 and is fast becoming a vital research tool in the very best global research institutions. Nano-Impact can operate at high strain rates and provides important additional information to nanoindentation. A wear test sample is shown in Figure 1.

Figure 1. Wear test sample.

The Principle of Nano-Impact

Two standard, unique impact or fatigue modes are included in the impact module in which a range of indenter types can be used. The indenter begins away from the sample surface before each impact, replicating true impact.

Probe Acceleration Impact for Low Cycle Fatigue

The features of the probe acceleration impact using the Nano-Impact are listed below:

  • With the use of solenoid activation the impact probe is accelerated rapidly over an accurately chosen distance for example, 10 µm above the sample to impact the surface at a very high strain rate.
  • Single and repetitive impacts are possible.
  • This approach is very popular to investigate work hardening, low cycling fatigue, dynamic hardening and yield stress.
  • Impact angle, applied load, indenter geometry and acceleration distance can be defined by the user.

Figure 2 shows individual impacts on a range of polymeric materials. The increased damping of PTFE is clear.

Figure 2. Nano-impact testing of polymeric materials.

Sample Oscillation Impact for High Cycle Fatigue

The features of sample oscillation impact for high cycle fatigue using the Nano-Impact are listed below:

  • Piezoelectric oscillation system, signal generator, amplifier and software for control and data analysis are the main components.
  • High cycle fatigue tests with oscillation frequencies up to 500 Hz and amplitudes up to 5 µm are possible.
  • Enables both impact and contact fatigue tests to be conducted based on the magnitude of the static load.

Figure 3 shows a repetitive Nano-Impact test on a 7-8% Yttria Stabilised Zirconia which is a thermal barrier coating that was previously aged for 24 hrs at 1500ºC.

Figure 3. Repetitive nano-impact tests for a YSZ thermal barrier coating.

The rapid Nano-Impact test shows the decreased resistance to multiple impacts after thermal ageing of the TBC that is stable with results from the erosion tests. Each point shown represents one impact.

Conclusions

The Nano-Impact allows the study of fatigue and fracture processes. It is possible to determine the probe acceleration impact for low cycle fatigue and the sample oscillation impact for high cycle fatigue.

About Micro Materials

Established in 1988 Micro Materials has continually been at the forefront of innovation, with our pioneering approach leading to three world firsts:

  • The first commercial nanoscale impact tester, for erosive wear, toughness and contact fatigue.
  • The first commercial high temperature nanoindentation stage, capable of reaching temperatures up to 750°C.
  • The first liquid cell, allowing the testing of samples which are fully immersed in a fluid.

Micro Materials provide innovative, versatile nanomechanical test instrumentation, and respond to developments in applications in response to customer and market requirements. The integrity, reliability and accuracy of our equipment is paramount, as is our relationship with our users.

This information has been sourced, reviewed and adapted from materials provided by Micro Materials.

For more information on this source, please visit Micro Materials

Date Added: Jul 5, 2011 | Updated: Jun 11, 2013
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