On the level of mechanical loss in metallic glasses

摘要

Metallic glass samples with compositions Zr₆₅Al_7.5Cu_27.5 and Pd₇₇Cu₆Si₁₇, for which loss factors of up to 10-2 have been reported, are reinvestigated with an electrostatic vibrating cantilever technique that detects dissipation factors tan δ as low as 10-4. It is found that tan δ ≈ 4×10-4 is a typical value for these alloys well below T _g , suggesting that previous results were limited by instrumental resolution. While aging the glasses increases their elastic moduli considerably, the measured loss factor is affected only marginally by thermal history.