By AZoNano Editors
Table of ContentsIntroductionOperating Principle of NanoTest VantageHardness and Modulus MappingDepth Profiling Load/Partial-Unload TechniqueIndentation CreepWide Load & Depth RangeConclusionsAbout Micro Materials
The NanoTest Vantage system combines a number of nanomechanical testing methods into one instrument. It offers excellent instrument stability over a wide load range. It can operate at temperatures up to 750°C, which means that it can be increasingly used to characterize high temperature and performance materials and components such as avionics and airframes across the aerospace industry. The NanoTest Vantage is fully compliant to all relevant international nanoindentation standards including ISO14577 and ASTM E2546–07.
Operating Principle of NanoTest Vantage
The NanoTest Vantage from Micro Materials uses application of electromagnetic force and capacitive depth measurement to measure the elastic and plastic characteristics of materials at the nano-scale.
Hardness and Modulus Mapping
It is good to see the distribution of modulus and hardness across a wider area instead of focusing on particular sites. By following this method, it is possible to highlight areas of non-uniformity because of structural anomalies, surface treatment variations or alterations in properties at joints and boundaries. The stability of the NanoTest Vantage ensures superior reproducibility of results over the entire duration of the test period. Figure 1 shows specifically targeted indents in gray cast iron.
Figure 1. Specifically targeted indents in gray cast iron
Figure 2 shows a 15 x 25 indent array (1µm pitch) mapping the hardness distribution and stiffness of intermetallic phases in a solder bond.
Figure 2. 15 x 25 indent array (1µm pitch) mapping the distribution of hardness and stiffness of intermetallic phases in a solder bond
Depth Profiling Load/Partial-Unload Technique
Conventionally indentation was conducted at one depth in the material. The investigation of how hardness and modulus vary from the surface moving further down in the sample is a field of great interest. The ‘load/partial-unload’ technique included in the NanoTest software allows load cycling that allows hardness and modulus measurements to be made at various depths in the sample in a single indent cycle.
Figure 3 shows the rapid profiling of hardness and elastic modulus as it varies with depth on a hard amorphous carbon film on a softer substrate.
Figure 3. Rapid profiling of hardness as a function of depth for a hard amorphous carbon coating on a softer substrate.
Figure 4 shows the inflexion point (a) in the multi-cycle indentation marks the transition to substrate-dominated load support. A significant elbow is seen on the unloading curve (b) which relates to a phase transformation.
Figure 4. Load versus depth profile showing inflexion point where properties transition from coating to substrate dominated.
In addition to providing dependable measurements of modulus and hardness, superior system stability allows longer duration tests such as indentation creep experiments. These can be used for extracting properties reliably such as the stress exponent or creep compliance and, in combination with the high temperature module, the activation energy for creep processes.
Figure 5 shows excellent agreement between fitted and experimental data for the creep of PMMA during a 700s hold at 100mN in the determination of the viscoelastic properties of polymers.
Figure 5. Creep behaviour of PPMA.
Wide Load & Depth Range
The NanoTest Vantage offers superior load & depth ranges, with a dynamic resolution system that optimizes the load and depth resolutions based on the peak load/depth set. This ensures superior resolution throughout the ranges. The high sensitivity and low noise floor enables accurate measurements of thin films for MEMS applications.
Figure 6 shows that for extremely small indentations into sapphire, contact is completely elastic. Increasing the load to 2mN causes it to reach the elastic-plastic zone.
Figure 6. Load/depth relationship for sapphire.
Figure 7 shows 10 indentations to peak loads of 100-500 mN on fused silica (blue) and sapphire (red).
Figure 7. Indentation to peak load behaviour of fused silica (blue) and sapphire (red).
The NanoTest Vantage enables accurate measurement of elastic and plastic properties of materials at the nano-scale. The instrument also enables hardness and modulus mapping with high stability. Indentation creep experiments are also possible with the instrument. The instrument also offers excellent load and depth ranges with a dynamic resolution system.
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