not yet, many ways only provide indirect proof.

Yes there is. Your question is probably too general. In solid state precipitation of metastable and stable phases from a solid solution occurs during a heat tretament and one can  investigate their appearance in the bulk, at grain boundaries and at dislocations in TEM (with all problems looking in a thin stripe and possible surface effects). This is a well investiagetd subject and goes back to the fifties/sixties of last century when TEM came up and revolutionized materials science. The same holds for crystallisation within an amorphous matrix being it metallic or conventional oxide glasses. This was recently used to study the inocculation in Al-alloys by Greer and Quested and lead to the now famous free growth model. For further information look into the book: K.F: Kelton, A.L. Greer, Nucleation in condensed matter, Pergamon Press, Oxford 2010.

Thanks Lorenz.

i am curious to know the heterogenous nucleation during solidification.

i am sure that your answer would help me.

I have not worked in this area. I have come across some references and please see whether these may be of help to your work.

Book on: "In-situ Electron Microscopy: Applications in Physics, Chemistry and Materials Science",  edited by Gerhard Dehm, James M. Howe, Josef Zweck, Wiley VCH, 2012, and the papers:-

1) "In Situ Electron Microscopy : Solidification of Eutectic Alloys", Clément Lemaignan and Joseph Pélissier (1981):  MRS Proceedings, 12, 241 doi:10.1557/PROC-12-241.

2) "Heterogeneous nucleation of solidification of cadmium particles embedded in an aluminium matrix", D. L. Zhang, K. Chattopadhyay, B. Cantor, Journal of Materials Science, 15 March 1991, Volume 26, Issue 6, pp 1531-1544.

3) "Observing classical nucleation theory at work by monitoring phase transitions with molecular precision", Mike Sleutel et al, Nature Communications,Volume:5,Article number:5598 DOI: doi:10.1038/ncomms6598

4) "HETEROGENEOUS NUCLEATION IN SOLIDIFYING ALLOYS, B. CANTOR and  R. D. DOHERTY, Acta Metallurgica, 1979, Vo. 27, pp. 33-46.

5) "Grain refinement of aluminium and its alloys by heterogeneous nucleation and alloying", B. S. Murty, S. A. Kori, and M. Chakraborty, International Materials Reviews, 2002, Vol. 47, No.1, page 3.

6) "Grain refining of aluminium and its alloys using inoculants", D. G. McCartney, International Materials Reviews, 1989, Vol. 34, NO.5, page 247.

Hi There

Of course there are various ways to observe in-situ heterogeneous nucleation. Levitation melting along with x-ray is the most useful way. However, technically, it requires highly precise facilities where you need to measure structure factor as a function of scattering vector. Furthermore, it depends on whether you wish to observe it pure metals or in compounds.

Cheers.

Reza.

Here another literature hint: MRS Bulletin 40 (2015) No.1 with the central topic: Frontiers in in situ electron microscopy. There are nice example in.

Regards

Lorenz

There are various techniques to observe of heterogeneous nucleation in alloys and metals.

I would like to see (in-situ) how nucleation takes place on TiB2 kind of particles (of sub-micro size) in liquid aluminium. OR similar systems.