Study of frequency dependence modulus of bulk amorphous alloys around the glass transition by dynamic mechanical analysis

A Dynamic Mechanical Analyzer (DMA) was used to study the frequency dependence of storage and loss moduli of amorphous Pd40Ni10Cu30P20 and La55Al25Cu10Ni5Co5 alloys over a broad frequency range around their glass transition temperatures. The amorphous samples were subjected to continuous heating at a constant frequency. Their storage moduli, E′, exhibited a similar sigmoidal change from a high solid state value to a low value of a supercooled liquid over the glass transition region but decaying at a different degree. The loss moduli, E″, were characterized by a relaxation peak. The peak frequencies obtained were then fitted to the Vogel–Fulcher–Tamman (VFT) equation and the scaling law equation.