Correlation Between Electronic Structure, Mechanical Properties and Stability of TE-TL Metallic Glasses

Mechanical properties (Young's modulus and hardness) of TE-Ni,Cu (TE = Ti, Zr and Hf) amorphous alloys increase approximately linearly with Ni, Cu fraction, x, over a wide composition range (fraction of Ni, Cu atoms ≤ 66 %). This correlates with the observed increase of the Debye temperatures with x and shows that the strength of interatomic bonding increases with x in these alloys. The thermal stability (e.g. the crystallization temperatures) of these alloys also increases with x, thus with increasing interatomic bonding. Since in all these alloys the electronic density of states at the Fermi level, N(EF), decreases linearly with x within the same x-range, a very simple relationship exists between the electronic structure and mechanical and thermal properties. We also estimate the mechanical properties of amorphous TEs (by extrapolating the properties of alloys to x = 0) and compare them with those of crystalline TEs.