Performing Nano-Mechanical Test in a Vacuum – NanoTest Xtreme

Table of Contents

Introduction
The NanoTest
The NanoTest Xtreme
Key Features of NanoTest Xtreme
Advantages of NanoTest Xtreme
Elimination of Drawbacks of Extrapolation
Spearheading Novel Research

Introduction

The demand to have test conditions closely resembling real-world situations is increasing among researchers in order to obtain the most precise, dependable prediction of properties.

Micro Materials, with its NanoTest Vantage, provides a complete range of nano-mechanical test solutions. Now, the addition of the NanoTest Xtreme offers vacuum environment testing from -100 to 850ºC with no sample frosting or oxidation.

The NanoTest

Micro Materials has the expertise to offer customers a variety of instruments that can perform high and low temperature testing. Until recently, the limitations of these have been oxidation at high temperatures and condensation/frosting at sub-zero temperatures. However, performing tests in vacuum conditions eliminates these issues and extends the temperature capabilities of the NanoTest.

The advantages to users include:

  • Improved low temperature capability to less than -100ºC without sample frosting
  • High temperature capabilities are extended beyond the 750 °C provided by the NanoTest Vantage
  • Full range of nano-mechanical tests are available, including scratch, indentation, friction, wear and high-load impact
  • Ultra-low thermal drift due to the proven construction principles already used on the NanoTest Vantage
  • Gas can be backfilled to match material operating conditions

The NanoTest Xtreme

The NanoTest Xtreme can be used to study the effect of more extreme environments for:

  • Low oxygen, low temperatures for satellite development
  • Tool coatings for high-speed machining
  • High temperatures for power station steam pipes
  • High temperatures for aerospace engine parts
  • Irradiation effects in nuclear reactor cladding
  • The effect of cold on weld repairs in oil/gas pipelines

Key Features of NanoTest Xtreme

The main features of the NanoTest Xtreme are listed below:

  • 10-5mbar vacuum (Figure 1)
  • 10µN - 500mN load range
  • High temperature stage integrated with the cryo stage provides a test temperature range from -100 to 850ºC
  • Backfill allows testing under alternative low oxygen environments
  • Equipped with a high-resolution optical microscope as a standard feature
  • 3D profiling stage
  • Can perform all standard NanoTest methods, including Nano-impact, Nano-fretting, Nanoindentation, and Nano- scratch and wear

Figure 1. Vacuum chamber of the NanoTest Xtreme

Advantages of NanoTest Xtreme

The key advantages of the Xtreme are as follows:

  • Proven NanoTest technology, offering reliable and accurate results
  • Extrapolating data from ambient conditions will no longer be needed for estimating the service-life performance
  • Vacuum, high and low temperature capability to suit the operating conditions of test materials
  • Provides the hardware for gaining insights into the mechanical performance of advanced engineering materials

Elimination of Drawbacks of Extrapolation

Extrapolating results from near-ambient or ambient temperatures generally produce unreliable and error- prone estimation of high and low temperature properties. However, testing in vacuum at a temperature range of -100 to 850ºC enables simulation of some of the most extreme environments that engineering materials can encounter. This feature allows accurate assessment behavior of advanced materials in a broad range of application areas.

Figure 2. Modulus data from glass-ceramic solid oxide fuel cell seal material at elevated temperatures. The results are from the same material heat treated at 800 ºC for different durations. This causes a reduction in the modulus of the 100 hour treated sample at room temperature. The benefit of the treatment is that the modulus remains more stable as the temperature is increased. This demonstrates the risks of extrapolating ambient temperature results to predict service temperature performance as it is impossible to predict the stabilizing effect of the heat treatment without relevant experiments.

The Xtreme test temperature range and vacuum environment provides the ideal capability for testing aerospace alloys in real service conditions. Alternatively, the ability to back fill the chamber enables replication of a broader range of oxygen reduced environments such as the carbon dioxide atmosphere that engine parts in automotive applications are exposed to.

Spearheading Novel Research

The NanoTest Xtreme enables scientist to perform research activities in areas that are inaccessible with traditional nanoindentation hardware, making it a very valuable instrument to aid the progress of materials research.

Research conducted at the University of Oxford with the Xtreme focused on extending the knowledge on silicon’s behavior at higher temperatures. Micro cantilever bending experiments are used to establish the mechanical properties at varied temperatures in order to analyze the changing deformation mechanics. Figure 3 depicts the typical load vs displacement data for bending experiments carried out at 110ºC and 700ºC. The silicon exhibits different behavior at the two temperatures, being ductile at 700ºC and brittle at 110ºC.

Figure 3. Data from micro-cantilever bending experiments on silicon.

The temperature at which the silicon’s behaviour transitions from brittle to ductile can be verified by high temperature nanoindentation measurements. Figure 4 illustrates indentation experiments conducted at different loads and at a temperature range of 500-650ºC. It can be confirmed that the material behaves differently beyond 500ºC from the change in the unloading behavior as well as from the increased creep during the hold at peak load.

Figure 4. Data from high temperature nanoindentation experiments on silicon performed in vacuum

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

For more information on this source, please visit Micro Materials.

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