| 摘要 |
<p>PURPOSE: To provide a percussion instrument made of a titanium alloy for the religious music or funerals and festivals by using a two-phase titanium alloy of the metal structure containing cubic system crystal grains having the aspect ratio of a specific value or below, and prolonging the reverberation time. CONSTITUTION: This percussion instrument is made of a two-phase titanium alloy of the metal structure containing cubic system crystal grains having the aspect ratio of 1.7 or below, preferably 1.2 or below. The two-phase titanium alloy capable of being ultra-plastically molded, e.g. a Ti-6Al-4V titanium alloy, is superplastically molded to manufacture the percussion instrument made of a titanium alloy for the religious music or funerals and festivals. It can be obtained by the normal plastic machining of the titanium alloy, however the machined structure contains slender crystal grains, and sound distortion is often generated by the anisotropy of the structure. The metal structure of this percussion instrument obtained by ultra-plastic machining contains nearly circular cubic system crystal grains having the average grain size in the range of 1.0-1.2μm, and it has little anisotropy of sound. The percussion instrument having a long reverberation time is obtained and an excellent effect is attained as the bell of a percussion instrument for the religious music or funerals and festivals.</p> |
