TY - JOUR
T1 - Formation of a 'splitting pattern' associated with L12 precipitates in Ir-Nb alloys
AU - Yamabe-Mitarai, Y.
AU - Harada, H.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2002/3
Y1 - 2002/3
N2 - A cuboidal L12 phase forms in the fcc matrix of an Ir-Nb alloy. Under some conditions, a rod- or plate-like fcc structure can be observed in this phase. This is similar to the 'splitting pattern' observed in some Ni-based alloys. To understand the formation mechanism of this structure, samples were heated under different conditions. Microstructure evolution during ageing was observed by transmission electron microscopy. We observed a splitting pattern only when the L12 precipitates were already formed in the as-cast condition after additional heat treatment at the ageing temperature. In this case, the composition of the L12 phase was not equilibrated. We conclude that the splitting pattern appears owing to a kinetic phenomenon when the L12 phase changes to the equilibrium composition.
AB - A cuboidal L12 phase forms in the fcc matrix of an Ir-Nb alloy. Under some conditions, a rod- or plate-like fcc structure can be observed in this phase. This is similar to the 'splitting pattern' observed in some Ni-based alloys. To understand the formation mechanism of this structure, samples were heated under different conditions. Microstructure evolution during ageing was observed by transmission electron microscopy. We observed a splitting pattern only when the L12 precipitates were already formed in the as-cast condition after additional heat treatment at the ageing temperature. In this case, the composition of the L12 phase was not equilibrated. We conclude that the splitting pattern appears owing to a kinetic phenomenon when the L12 phase changes to the equilibrium composition.
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U2 - 10.1080/095008302317262606
DO - 10.1080/095008302317262606
M3 - Article
AN - SCOPUS:0036507697
VL - 82
SP - 109
EP - 118
JO - Philosophical Magazine Letters
JF - Philosophical Magazine Letters
SN - 0950-0839
IS - 3
ER -