Short range order of amorphous Mg60Cu30Y10 was investigated by x-ray and neutron diffraction, Cu and Y K-edge x-ray absorption fine structure measurements, and the reverse Monte Carlo simulation technique. We found that Mg-Mg and Mg-Cu nearest neighbor distances are very similar to values found in crystalline Mg2Cu. The Cu-Y coordination number is 1.1 +/- 0.2, and the Cu-Y distance is similar to 4% shorter than the sum of atomic radii, suggesting that attraction between Cu and Y plays an important role in stabilizing the glassy state. Thermal stability and structure evolution upon annealing were also studied by differential scanning calorimetry and in situ x-ray powder diffraction. The alloy shows a glass transition and three crystallization events, the first and dominant one at 456 K corresponding to eutectic crystallization of at least three phases: Mg2Cu and most likely cubic MgY and CuMgY.
Bibliographical noteCopyright 2007 American Physical Society
- CASTING METHOD
- METALLIC GLASSES
- BULK AMORPHOUS-ALLOYS