Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10655817 | Intermetallics | 2005 | 8 Pages |
Abstract
The thermal stability and crystallization kinetics of Cu47Ti33Zr11Ni8Si1 gas atomized powder (GAP) and composite powder reinforced with 25 vol.% nanosized Cu second phase particles introduced by ball milling was studied by differential scanning calorimetry in the mode of continuous heating and isothermal annealing. Ball milling leads to successful incorporation of Cu particles within the GAP matrix and hence offers itself as a useful technique to prepare composite microstructures. In the case of continuous heating, both the glass transition temperature Tg and the crystallization temperature Tx display a strong dependence on the heating rate. The activation energy, as determined by the Kissinger equation, for the first order transformation was found to be almost identical for the GAP (3.53±0.12 eV) and composite powders (3.59±0.06 eV). The isothermal transformation kinetics were modeled by the Johnson-Mehl-Avrami (JMA) equation. The values of the JMA exponent imply that the crystallization of the metallic glass GAP as well as the composite powder is governed by diffusion-controlled three-dimensional growth. The activation energy of crystallization derived from isothermal annealing experiments is nearly the same for the GAP (3.69±0.20 eV) and the composite powders (3.78±0.10 eV). The addition of Cu particles does not noticeably affect the crystallization kinetics of the amorphous matrix composites.
Keywords
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Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
S. Venkataraman, E. Rozhkova, J. Eckert, L. Schultz, D.J. Sordelet,