Professor Roger Reed is a world leader in the engineering and science of high-temperature alloys, with a particularly strong focus on nickel-based superalloys. These materials are used extensively in engine and power generation applications due to their excellent mechanical properties at elevated temperatures.
Dr Tony Yang using the Plastometer. Image Credit: Plastometrex
Roger leads a research group at The University of Oxford that develops new superalloy systems that can be made via additive manufacturing (commonly known as 3D printing). Printable superalloys systems would enable new parts to be designed with greater geometric freedom, prototyped far faster, and produced with minimal material wastage.
The advantages of metal additive manufacturing are clear, however in practice, changing the manufacturing method of a material comes with significant research challenges. Legacy superalloys have been designed to be made via traditional casting approaches, which are fundamentally different to additive manufacturing. Printed materials are built by flash-melting layers of metal powder with a laser, fusing them together to make a solid material.
This process is repeated layer-by-layer with a high degree of geometric control to create a finished part. The very rapid heating and cooling processes that occur during printing can strongly impact the materials microstructure and its resultant mechanical properties, leading to parts with potentially compromised structural performance.
In order to tackle this problem, Roger and his team have pioneered an alloy-by-design methodology. This uses computational tools to screen different elemental compositions, exploring the relationship between their chemistry and material properties. The approach allows researchers to navigate millions of possible alloy compositions, enabling them to select the most promising candidates for production and physical testing.
Importantly, alloy-by-design empowers researchers to design whole new alloy systems specially for production via additive manufacturing. The result is novel superalloy compositions that retain the excellent mechanical performance of the legacy cast grades even when made via modern printing techniques.
A key part of this alloy design process is to be able to validate these numerical models quickly with high throughput physical testing. To do this Roger and the team at Oxford recently invested in an Indentation Plastometer device from Plastometrex.
The bench-top system is capable of measuring accurate material strength (in the form of stress-strain curves) from an automated 3-minute indentation test. This technology reduces both the testing times and materials required for testing by over 90%, allowing the team at Oxford to design and prototype alloy grades far faster than other research groups working in the same field.
The Indentation Plastometer enables us to reduce our physical testing times from days to just a few minutes. This has had a massive positive impact on our alloy design research, enabling us to navigate, select and validate new materials faster than ever before.
Professor Roger Reed
Plastometrex and the team at Oxford also have strong collaborative ties, recently co-authoring a publication in Advanced Engineering Materials. The work explores how the Indentation Plastometer can be used to characterise the properties of small samples of anisotropic superalloys. In this work it was shown that the Plastometer can give a semi-quantitive measure of anisotropy (an effect where materials exhibit different properties on different directions).
Bill Clyne, Chief Scientific Officer at Plastometrex, said this about the relationship:
We are delighted to be working with the team at Oxford, who are world leaders in the metallurgy of additive manufacturing. We look forward to continue to collaborate with Roger and his team as we push the frontiers of mechanical materials testing.
Bill Clyne, Chief Scientific Officer at Plastometrex