Response to Thermal Exposure of Ball-Milled Cu-Mg/B2O3 Powder Blends

The response to thermal exposure of ball-milled Cu-Mg/B2O3 powder blends was investigated in the current study to explore the potential of powder metallurgy route to produce Cu-B alloys. Cu-20Mg alloy powder was mixed with B2O3 and subsequently ball milled for 1 hour. Ball milling alone failed to establish a reaction between Cu-Mg compounds and B2O3. When the ball-milled powder blend was heated, however, B2O3 was reduced by CuMg2 <773 K (500 °C). The Cu2Mg intermetallic phase, which has survived until 773 K (500 °C), was involved in the reduction of the remaining B2O3 at still higher temperatures, while excess Mg reacted with B to produce MgB2 and MgB6 compounds. Cu-Mg alloy with predominantly the CuMg2 phase must be utilized to take advantage of the capacity of the CuMg2 (Cu-43 wt pct Mg) compound to reduce B2O3 at temperatures as low as 773 K (500 °C). Once the Cu-43Mg alloy powder is mixed with B2O3 and the powder blend thus obtained is ball milled and subsequently heated at 500 °C, B2O3 is readily reduced by CuMg2 to yield Cu, B, and MgO. The latter can be easily removed from the powder blend by acid leaching.