A NOVEL WAY OF AMORPHOUS PHASE-FORMATION DURING MECHANICAL ALLOYING OF COPPER AND CADMIUM POWDERS

Phase formation during high-energy ball milling of copper and cadmium powders has been investigated. Both X-ray diffractometry (XRD) and dif ferential scanning calorimetry (DSC) have been used to characterize th e resulting phases. An amorphous phase forms during milling in the cop per-cadmium system by a reaction between the equilibrium delta phase a nd one of the constituent metals (copper). However, the amorphous phas e cannot be produced by a direct reaction between the copper and cadmi um powders, nor by milling of a powder consisting of only the delta ph ase. It appears most likely that the contribution from the generated c opper/delta interfaces, and the accompanying increase in the total fre e energy, provide the additional driving force for the amorphous phase formation in: this system.