| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 93 === Abstract
Ren-Jay Hieh
This study focused on the damping capacity of TiNiCu ternary shape memory alloys and of Zr-based amorphous alloys, Zr55Al10Ni5Cu30. The damping values, tanδ, at transient peaks of Ti50Ni35Cu15 and Ti51Ni41Cu8 are both over 0.05 at cooling rate of 3℃/min with frequency 1Hz; after keeping the peak temperature for 30mins and above, the tanδ values of Ti50Ni35Cu15 and Ti51Ni41Cu8 are both descends over 82%. On the other hand, the tanδ values at relaxation peaks don’t drops dramatically after keeping peak temperature, however, they ascends with increasing amplitude. Comparing to TiNiCu shape memory alloys, Zr-based amorphous alloys have lower damping capacity but higher strength, However, its tanδ values increase with larger amplitude. Hydrogenation improves the damping capacity of Zr-based amorphous alloys with thinner thickness remarkably, the tanδ value at cooling rate of 3℃/min with frequency 1Hz exceeds 0.01 after hydrogenation under 100mA/mm2 current density for 2 hrs, but hydrogenation can’t improve the damping capacity of Zr-based amorphous alloys with higher thickness as well, it might due to the difference of H atoms diffusing into specimen result from the different thickness.
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