Nanoindentation for Nano-mechanical Testing (Nanoindentation)
Nanoindentation for Nano-mechanical Testing (Nanoindentation)
Nanoindentation is a proven method for conducting mechanical indentation tests on very small samples (Nano-mechanical Testing). Conventional indentation testing instruments do not measure micro-forces, or displacements and indentation areas at micron or nanometer scale. Nanoindentation testing involves the use of high-precision instruments as well as analytical software. The Nanoindentation technique utilizes a sharp indenting probe of defined geometry. Typically, a calibrated Berkovich diamond tip, shaped like a three-sided pyramid, capable of being sharpened to an atom size point, is used in Nanoindentation for Nano-mechanical testing. It is possible to have tips with in-situ SPM (scanning probe microscopy) capability, providing high resolution imaging of the specimen before and after indentation.
The Nanoindentation test is performed by pressing the indenter tip into the sample by applying a linearly increasing force. Once the targeted force is reached, the loading is continuously decreased until partial or complete relaxation of the sample occurs. The tip displacement and applied load are continuously recorded. For nanomechanical testing, the applied force is in the nanoNewtons to milliNewtons range and displacement is also of the order of microns or nanometers. The indentation area is computed from the tip geometry. A short pause at maximum load allows investigation of creep properties. The recorded load and displacement data, along with the calculated indentation area are used to determine mechanical properties such as elastic modulus and hardness. Various other loading modes are also possible, to determine a range of properties. These include cyclic loading for measuring fatigue or plastic-elastic deformation and Dynamic Mechanical Analysis (DMA) for obtaining visco-elastic properties of samples.
The Nanoindentation technique can be applied to a wide range of metallic and non-metallic materials, to determine a range of mechanical properties such as hardness, elastic modulus, fracture toughness, creep and dynamic properties such as storage and loss moduli.
Common Uses of Nanoindentation for Nanomechanical testing
- Hardness testing of thin films and coatings on metals and semiconductors
- Scratch and wear testing at micron depth, of metallic and non-metallic components
- Nano-Mechanical Properties of biomaterials and biocomposites at cellular level
- Mechanical testing of nanocrystalline alloys
- Nano-scale mechanical characterization of polymers and composites
Advantages of Nanoindentation for Nanomechanical testing
- More precision in mechanical testing of thin films and coatings
- Mechanical Testing of metals and alloys at single crystal level
Limitations of Nanoindentation for Nanomechanical testing
- Probe construction limits the achievable precision at nanoscale
- Influence from the matrix and adhesion effects can influence results in testing of coatings and soft materials
- Extremely rough surfaces are difficult to test at nanoscale
Industrial Applications of Nanoindentation for Nanomechanical testing
- Semiconductor and thin film quality control
- Polymers and composites testing
- Metallurgical testing
- Mechanical Failure analysis of metals and non-metals
- Industrial Adhesives and coatings testing
