Structure Changes of Cu-Sn-Pb Alloy by Mechanical Grinding

Abstract

A high energy type ball-milling machine for mechanical grinding (MG) was used to examine its effectiveness of redistributing the insoluble slolute of Pb in the Cu-Sn-Pb alloy powders and the structures of these MG powders were also discussed. The sufficiently deformed and pulverized powders were attained after a milling time of about 20hr, and composed substantially from the crystallites of Cu and Pb the diameter of which was about 10nm. In some parts of these powders, an amorphous-like structure could be observed by TEM but not by XRD. The formation of stacking faults during milling was confirmed in Cu by pesk shifts of (111)_Cu and(200)_Cu reflections of XRD. The result of DSC measurements carried out on the MG powders showed the stored energy in the MG powders was estimated to be about 3 kJ/mol irrespective of Sn content and less than one-third of the mixing free energy of the supercooled liquid Cu-Pb alloy.