Several Observations on the Deoxidized Large Copper Grain

Abstract

The effects of the deoxidizer on the microscopic structure and the strength of anode Cu ingots for X-ray tubes were investigated. A small amount of Si and CaSi were used as the deoxidizer. A clear dendritic structure which might be attributed to the segregation of minor impurities was observed in the grain by HNO₃ etching. The grain boundary of the specimen deoxidized by Si showed a straight form and fractured always at the boundary above 600°C, while the boundary of CaSi-deoxidized specimen showed irregular form and didn’t always fracture at the boundary. From these facts it was presumed that the concentration of impurities at the grain boundary of the former specimen might be higher than that of the latter.