Rotational deformation stage for the characterisation of materials
Analysing the deformation mechanisms of both industrial and geological samples is crucial for understanding how they will behave under the action of a force. The ability to view the deformation under a scanning electron microscope (SEM) allows for a deeper understanding of the deformation process, yet traditional apparatus can impose only a limited spectrum of deformations on samples. This is because it deforms samples in extension, and so the space available on the stage restricts the maximum elongation that a sample can undergo.
Academics at Oxford University have developed a novel deformation stage for use on existing SEMs that allows larger deformations to be applied in a small and compact geometry, by applying a torque to the specimen rather than elongating it. These (and other) benefits will be invaluable to any analysis of the mechanical properties of a wide range of materials, across both industry and geology.
When characterising both industrial and geological materials, it is important to understand the microphysics of how they deform under the application of a force. It can be particularly useful to deform a sample whilst viewing it under a scanning electron microscope (SEM) at the same time so that the exact mechanisms of deformation can be known.
Traditional deformation stages used in SEMs deform the samples in extension. These are limited to very small deformations due to three main factors:
- The space available on the stage, this restricts the maximum elongation
- Samples in extension have a tendency to fail even after small deformations of this type
These limits on the deformation place a limit on the spectrum of material behaviour that can be investigated.
Academics in the Earth Sciences department of the University of Oxford have developed a novel deformation stage for use on existing SEMs that allows for the deformation of the sample in a rotational geometry. By applying a torque to the centre of a specimen whilst fixing the outer edges in place, a velocity gradient is imposed along the sample surface, without the apparatus changing in dimensions.
This provides a number of benefits compared to traditional methods:
- Large deformations can be obtained in a very small space
- The surface can be imaged by a SEM during the deformation
- The apparatus is easily incorporated into existing SEMs
- The geometry is simple and compact
- The sample does not change shape, preventing sample failure at large deformations
This deformation stage can be used for the in situ investigation of the mechanical properties of a wide range of materials, both industrial and geological. The technology is subject to a patent application and is available for license.
For more information about the technology and licensing opportunities, please contact Oxford University Innovation.
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