BEHAVIOR OF CU-CR POWDER MIXTURES DURING MECHANICAL ALLOYING

In the present work, the behavior of Cu-Cr powder mixtures during mechanical alloying has been studied. The powder mixtures with 1, 3 and 6 weight percents of Cr in Cu were treated. They were milled in a ball mill with two different speeds of 250 and 500 rpm using equal numbers of 1 and 2 centimeters balls. The weight ratio of balls to powders was 10 to 1 under argon atmosphere. Ethanol was used as the process control agent and milling times were 4, 12, 48 and 96 hours. After every hour of milling, a half-an-hour stop was applied to avoid temperature rise. The milled powder mixture was evaluated by a scanning electron microscope equipped with energy dispersive spectroscopy and an optical microscope equipped with image analyzer. Results have shown profound effects of milling conditions (the change in time, speed, etc.) on the behavior of milled powders.