Unlocking cryogenic material behaviour with novel cryostat

National Composites Centre (NCC) has demonstrated the use of its novel cryostat to screen a wide selection of materials at cryogenic temperatures. The low cost method highlights the best candidates for detailed material testing using conventional methods.

Multiple cryostats have been developed and released including; microcrack fracture toughness and shear fixtures, with others, such as impact, under development.

Understanding properties of materials at cryogenic temperatures is time consuming and costly, with limited existing UK capability. Driving transformational change in the field of cryogenics, the capability introduced by NCC will reduce the time, cost and complexity of cryogenic testing.

The 3D printed cryostat that has been developed provides the capability to rapidly screen cryogenic material properties, whilst providing insight into failure mechanisms. A video of the material test in action can be viewed here which shows the forming of microcracks in a thermoset sample under tension at approximately –160°C. The cryostat shown is an early iteration that has since been developed.

Allowing material specimens to be viewed live during the test process to identify ‘microcracking’ is achieved via optical access, a key feature of the device. The test has a cycle time of under an hour to cool and test, allowing a high throughput of test specimens. This is achieved by using cryogenically cooled nitrogen gas, utilising a design with a low thermal mass and volume. Utilising a tensile testing machine, no modifications to existing test machines are required.

Leading the cryostat development project, Matt Kay, Principal Engineer at the National Composites Centre said “The cryostat concept allows the rate of cryogenic materials testing to significantly increase, helping engineers and researchers to learn quickly and cost effectively, reducing the burden in developing new products for the emerging liquid hydrogen industry.”