Heating rate dependence of two glass transitions and phase separation for a La55Al25Ni20 amorphous alloy

The heating rate dependence of two relaxation systems for two glass transitions for a La55Al25Ni20 amorphous alloy was examined through the changes in storage, E', and loss, E double-prime, moduli. The appearance of the higher temperature relaxation in E'(T) shifts to higher temperatures with increasing heating rate, The higher temperature relaxation peak in E double-prime(T) shifts to higher temperatures though the lower temperature peak slightly shifts to lower temperatures with increasing heating rate. Under the transmission electron microscopic observation, the amorphous phase shows a phase separation during heating. The effect of the heating rate on the phase separation causes the change in E'(T) and E double-prime(T) behavior with the heating rate. The glass transition temperature obtained by calorimetric measurement also shifts to higher temperatures with increasing heating rate reflected by the higher temperature relaxation