Published online by Cambridge University Press: 21 February 2011
The short melt duration resulting from pulsed laser and electron beam surface melting of ion-implanted metals has been used to measure precipitate nucleation times of compounds within the melt. We have examined the phases present in several alloy systems with TEM and used calculated thermal histories to place limits on the time required for nucleation of the following compounds: AlSb (5–25 ns), Al3Ni (≳ 750 ns)Al3Ni2 (≳ 950 ns) and AlNi (< 1000 ns), all in molten Al, and TiC (≲ 100 ns) in molten Fe. The compounds observed after our rapid solidification have relatively simple, cubic structures and melt congruently, while those predicted but not observed have more complex structures and decompose peritectically.
This work performed at Sandia National Laboratories supported by the U.S. Department of Energy under contract #DE-AC04-76DP00789.