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U.S. Department of Energy
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Spinodal-like decomposition of Fe-Ni and Fe-Ni-Cr alloys in both radiation and non-radiation environments

Technical Report ·
OSTI ID:6776541

The radiation-induced development of spinodal-like compositional fluctuations in Fe-Ni-Cr invar alloys leads to several fortuitous methods of visualizing the three-dimensional nature of the decomposition process. In low dose neutron-irradiated Fe-Ni-Cr specimens, the use of high electropolishing rates during preparation of microscopy foils leads to a preferential attack of those regions which are low in nickel. In high dose ion-bombarded specimens of Fe-35Ni, the absence of chromium leads to formation of cellular martensite in the nickel-poor regions upon cooling to room temperature. The scale of the fluctuations at temperatures >600/sup 0/C is comparable to that found in the Santa Catharina meteorite, which is roughly Fe-35%Ni in composition. This and other non-radiation data support the proposal that the Fe-Ni system in the absence of irradiation tends to spinodally decompose in the invar regime but at a very sluggish rate. Thus it appears that radiation accelerates rather than induces the decomposition of Fe-Ni and Fe-Ni-Cr invar alloys.

Research Organization:
Hanford Engineering Development Lab., Richland, WA (USA)
DOE Contract Number:
AC06-76FF02170
OSTI ID:
6776541
Report Number(s):
HEDL-7633; ON: DE87005496
Country of Publication:
United States
Language:
English