한국주조공학회

Microstructure of the bell made with Cu-Sn alloys was examined by optical and scanning electron microscope and that ana- lyzed quantitatively with image analyzer. Also acoustic characteristics of the bells were measured in detail by using FFI‘ type power spectrum analyzer. 0:-single phases of large grains only were observed in Cu-5%Sn alloy. However mixed structure of pri- mary cx-phase and eutectoid of oc+5%o was existed in the Cu-Sn alloys with more than 9%Sn. Also the area fraction of eutectoid phases gradually increased with an increased Sn content. From the result of acoustic test, it was found that frequency and tonal intensity decreased with the increased Sn content from 5%Sn to ll%Sn, and those were rather increased with further increase of that. The lowest frequency and tonal intensity were showed in Cu-l 1 %Sn, and porosity decreased considerably frequency and tonal intensity of the bells.

Cu-Sn alloy, bell, microstructure, acoustic characteristics porosity