Modification of Copper

Abstract

The requirement of modification of copper is proved in the article. As a modifier for copper the misch metal is proposed. The misch metal contains rare earth elements having greatest modifying ability. The results of experiments of the influence of misch metal in an amount from 0.0025 to 0.0125 wt. % on the formation of crystal structure of cast copper with different impurity content are presented. The metallographic analysis of macrostructure of copper is made and the average area of cross section of grains in the structure of copper is determined. The average area of cross section of grains in the structure of copper of brand M00 decreases from 5 to 0.9 mm2 with addition of 0.005 wt. % of misch metal. The average area of cross section of grains in the structure of copper of brand M1 decreases from 6 to 0.45 mm2 with addition of 0.005 wt. % of misch metal. An increase of quantity of added misch metal more than 0.005 wt. % dose does not lead to significant decrease of average area of cross section of grain in the structure of copper. The investigation of microstructure of samples of cast copper of brands of M00 and M1 is made. It is established that the addition of misch metal in the copper dose does not lead to increase in the thickness of the grain boundaries. The results of experiments are shown that addition of misch metal in the copper leads to increase of stregth and plastic properties of copper. Based on the results of experiments the mechanism of modification of copper is proposed.