On the level of mechanical loss in metallic glasses

摘要

Metallic glass samples with compositions Zr_(65)Al _(7.5)Cu_(27.5) and Pd_(77)Cu_6Si _(17), 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.