Abstract: Electric resistivity measurements and X-ray diffraction analysis were performed to study the isothermal phase transformation in amorphous Au-Si ribbons with eutectic composition pre- pared using melt-spinning technique.A series of phase transformations take place spontaneously at room temperature and accelerate at elevated temperatures.Four stages of the transformation from amorphous state to the equilibrium state can be distinguished.Dis- cussion on the structural character of the metastable phases indicates that Hume-Rothery electron compounds and size factor compounds could form during isothermal aging.

Key words: Au-Si amorphous alloy, isothermal phase transformation