Full Record for Micrograph 614

Link to full size image of micrograph 614

[69 KB]

View micrograph
.. in new window

View micrograph and record
.. in new window

You can also view and download the micrographs on Flickr

Micrograph no: 614
Brief description: Rapid solidification in an atomised droplet
Keywords: alloy , atomising , droplet, hypercooled, latent heat , metal, rapid solidification, recalescence, soldidification
Categories: Metal or alloy
System: Al-Mg
Composition: Al 90, Mg 10 (wt%)
Standard codes
Reaction: N/A
Processing: Rapid solidification of an atomised droplet
Applications: Rapid solidification processing reduces the scale of microsegregation and increases solid solubility (allowing subsequent fine-scale precipitation). 'Glassy' (vitrified) metals can be produced.
Sample preparation
Technique: Transmission electron microscopy (TEM)
Length bar: 500 nm
Further information: Because of the fine scale of the droplet, heat extraction is very rapid, and large undercoolings are achieved before crystal nucleation can begin. Thus, in this droplet, the solidification front has advanced very rapidly through the droplet from the nucleation point (on the surface at the left of the image). Its velocity is initially so great that no interfacial breakdown is possible. As the front advances, however, latent heat is evolved and this 'recalescence' reduces the rate of solidification to a point where interfacial breakdown is possible and a cellular structure is observed in the last region to solidify (at the right hand side of the image).
Contributor: Prof T W Clyne
Organisation: Department of Materials Science and Metallurgy, University of Cambridge
Date: 03/10/02
Licence for re-use: Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales