Abstract
This study is concerned with the effects of Se addition on macro segregation of Bi of CAC911 copper alloy, and the effects of P and Ni addition on solidification structures and mechanical properties of CAC912 copper alloy with improved high temperature tensile strength over CAC911 copper alloy. In case of CAC911 copper alloy, step bar casting and an interrupted solidification process were carried out to examine the effects of Se addition on solidification structures. As a result, it was found that addition of Se reduced the inverse segregation of Bi, and improved distribution of fine porosities. In case of CAC912 copper alloy, a 180℃ tension test and unidirectional solidification were carried out to examine the effects of P and Ni additions on solidification structures and mechanical properties. As a result, it was found that P addition improved the strength of grain boundary at higher temperatures, and improved the 180℃ tensile strength. Single addition of Ni did not improve 180℃ tensile strength, but addition of Ni with P did.
