Electron irradiation induced crystallization behavior in Zr66.7Cu33.3 and Zr65.0Al7.5Cu27.5 amorphous alloys

Electron irradiation effects on the phase stability and microstructure change of conventional Zr66.7Cu33.3 amorphous alloy and Zr65.0Al7.5Cu27.5 metallic glass were examined. The amorphous phase was unstable under electron irradiation at 298 K and f.c.c.-Zr2Cu precipitates were formed. Although b.c.t.-Zr2Cu with coarse grains precipitated from the amorphous phase by thermal annealing, a nanocrystalline structure composed of f.c.c.-Zr2Cu precipitates and amorphous matrix was obtained by electron irradiation. There was a threshold total dose density for electron irradiation induced crystallization. The density for Zr65.0Al7.5Cu27.5 was larger than that for Zr66.7Cu33.3. The b.c.t.-Zr2Cu precipitates in thermal equilibrium were unstable under electron irradiation and were transformed to f.c.c.-Zr2Cu through the amorphous phase.