Silver and nickel are mutually only very slightly soluble and have a positi
ve heat of mixing. Ag50Ni50 powder was prepared by mechanical alloying (MA)
for 200 h and subsequent hot pressing (HP) at 620 degrees C under 60 MP3,
XRD results indicated that ball milling produced a two-phase mixture of sup
ersaturated, nanocrystalline Ag-rich (alpha-phase) and Ni-rich (beta-phase)
solid solutions with grain sizes of 5 and 3 nm, respectively. The grain si
zes increased to about 40 and 3-6 nm after hot pressing. The HP Ag50Ni50 ha
d a density very close to the theoretical value. The HP alloy consisted of
an interconnected network of the alpha-phase and islands of a two-nanophase
mixture rich in the beta-phase. The tability of the microstructure of the
alloy and the effects of mechanical alloying on the supersaturation of the
two phases and on the formation of the Ag-rich network are also discussed.
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