SOLIDIFICATION OF UNDERCOOLED CU, CU-O AN D CU-S ALLOYS

Undercooling and solidification phenomena of Cu and Cu-O and Cu-S allo ys were investigated. The ''one-way nucleation'' of Cu/Cu2S eutectic w as also examined. The undercooling of Cu-O and Cu-S alloys increased w ith increasing oxygen or sulfur content. This may be caused by oxidati on or sulfurizing of effective nucleants in molten copper, or by the s urfactant roll of oxygen and sulfur. Regarding the ''one-way nucleatio n'', the Cu phase nucleates the Cu2S phase at small undercooling, but the Cu2S phase does not nucleate Cu.