The compressibility of nanostructured Fe-Cu materials prepared by mechanica
l milling has been investigated by in-situ high-pressure x-ray diffraction
using synchrotron radiation. It is found that the bulk modulus of both fcc-
Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable fe
rromagnetic fcc-FeCu solid solution prepared by mechanical alloying has a b
ulk modulus of about 85 GPa, which is much smaller than the corresponding v
alues for bulk fcc-Cu and bcc-Fe. (C) 1999 Acta Metallurgica Inc.