Miniaturised experimental simulation of ingot-to-billet conversion

Ingot-to-billet conversion processing, or "cogging", is an important production step in high-value metallurgical manufacturing. It is necessary to homogenise and refine the microstructure of high-performance alloys before they proceed to subsequent processing stages, such as hot-forging. Despite its importance, the process is still not very well understood for many modern advanced alloys and few published studies exist. The limited knowledge of the deformation and microstructure evolution leads to difficulties in achieving the desired accuracy of microstructure control. Given significant costs of large multi-tonne workpiece ingots and the difficulties with their non-destructive evaluation, it is crucial to develop a laboratory-scale evaluation for the cogging process so that scrapping and re-processing can be avoided.
Over the course of the project the student will develop automated apparatus to cost-effectively simulate cogging on a laboratory scale, whereby test specimens will be rotated in synchronous alternation with compressive deformation at elevated temperatures. A commercial high-temperature superalloy will be used for the study to help gain an improved understanding of plastic deformation during cogging and optimise the processing conditions. The student will use digital image correlation and crystal orientation mapping (electron back-scatter diffraction, EBSD) to measure how deformation is localised within the different microstructural features of the alloys.