engleski

Simple correlation between mechanical and thermal properties in TE-TL (TE=Ti, Zr, Hf ; TL=Ni, Cu) amorphous alloys

It was shown recently [1] that mechanical properties (stiffness and hardness) of Zr-TL amorphous alloys (TL = Ni, Cu) increase approximately linearly with TL content over a wide composition range (x(TL) ≤ 65 at%). This correlated with the increase in the Debye temperatures and thermal stability (e.g. the crystallization and glass transition temperatures) with x and showed that the strength of interatomic bonding in these alloys increases with x. Here, we provide new data for the Young, s modulus, microhardness, Debye temperatures and crystallization temperatures for several Ti-TL and Hf-TL amorphous alloys covering wide composition ranges. These data, combined with published data in the literature, show, qualitatively, the same behaviour as that previously observed for Zr-TL alloys [1]. Thus, the strength of interatomic bonding in all TE-TL amorphous alloys (TE = Ti, Zr, Hf) increases with x for x ≤ 65. The correlation between mechanical properties and thermal stability is discussed in terms of recent models for glass forming ability. The observed approximately linear variation of mechanical and thermal parameters with x enables one to estimate these parameters for pure amorphous TEs. Since, in amorphous TE-TL alloys the electronic density of states at the Fermi level decreases linearly with x [2], a very simple relationship exists between the electronic structure and mechanical and thermal properties.

metallic glasses; rapid-solidification; quenching; mechanical properties

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