Early stages of precipitation – Copper precipitation

Last year I attended a conference on Early stages of Precipitation, which was a paralled session organised by the Royal Microscopical Society (Not to be confused with this other RMS).

George Smith (etal) reported that in the early stages of copper precipitation, precipitation can be accelerated by additions of Nickel, despite the fact that we do not expect Nickel to segregate from thermodynamic calculations (based on continuum assumptions). Atom probe results show that Nickel segregates to the boundary between the two phases, this was explained by consideration of pair-wise interaction energies. Modelling was performed using a Monte-Carlo scheme which reproduced the observed precipitation sequences based on interaction energies.

Nickel is friendly to both Cu and Fe, while Cu-Fe don’t get on together so well.

From this type of explanation we should be able to make a prediction of which alloying elements can similarly accelerate or diminish the formation of clusters/ nuclei.

To do this I would like to calculate or find a table of interaction energies.


One Response

  1. Hi Mathew

    This sounds interesting, I did some work for my master’s project on the influence of Mo on the precipitation of Cu in maraging steels. The steel also contained Ni but its content was fixed.

    The results were that additions of Mo accelerated the precipitation process just after 5 minutes of aging showing the presence of Cu clusters that were not observed in the unaged samples. Moreover there was no evidence of Mo precipitation. I know that Mo and Cu are inmiscible up to temperatures around 900 C but I did not go further trying to find the relation with their interaction energies.

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