Tech transfer with Rolls Royce
A connection between understanding carbonate diagenesis and the rate at which aircraft can climb to cruising altitude might not be apparent. But in recent years we have been involved in precisely this, which has now appeared in a publication by a group of engineers from Rolls Royce (Hardy et al., 2024; see clip of front page).
In essence Rolls Royce had been developing new methods of casting the ‘christmas tree’ central part of the next-generation engines in order to allow more efficient climb rates for commercial jets (because a faster rate of climb to cruising altitude is both financially attractive, and better in terms of factors such as CO2 emissions). However, the standard form of QC for imperfections (counting the number of inclusions via SEM within the resulting alloy) became difficult to detect and measure in these new alloys using their standard techniques, so we were asked to undertake a study of inclusion luminescence and provide data on inclusions over 30um in size. Fortunately, inclusions are readily identifiable because they show up with a variety of bright luminescent colours, whilst the ‘matrix’ metal is non-luminescent. We’re not saying that this was easy with CL: to some extent it was a bit like trying to make a map of the night sky with a pair of binoculars. It’s very difficult to focus something that is completely non-luminescent and your brain plays tricks with what you see rather in the manner of looking at a mirage in a desert. But the results were sufficiently encouraging in terms of finding larger features, that proof of concept was established for future reference.
Interestingly, inclusions had variable size and luminescence spectra, the reasons for which are presently unclear; this could be to do with inclusion composition and/or structural-crystallographic reasons. Usually, they appear not as a single feature but as an array of luminescent points, rather like a star constellation. The largest and most spectacular examples show more consistent patterns of luminescence change from interior to exterior (see example; FOV of clip is approx. 100um).

