Abstract
The ordered structure of Fe-40Al B2 powders has been disordered and nanocrystallized using a high energy ball-milling. The progress of disordering was followed by X-ray diffraction and magnetic measurements. The long-range order parameter presents a monotonie decrease with milling time and it is accompanied by a reduction in the mean crystallite size, attaining nanocrystalline dimensions, an increase in lattice strain and a significant lattice expansion. Evidence of the atomic disorder is also obtained from the observation of the continuous increase of saturation magnetization upon milling time. The reordering process of the originally nanocrystalline metastable alloy was investigated under continuous heating conditions by means of differential scanning calorimetry and thermogravimetric magnetic measurements. The reordering enthalpy and the apparent activation energy of the reordering process were evaluated. Reordering has also been studied after isothermal annealings. The possible mechanisms involved in the reordering process are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 395-400 |
| Journal | Materials Science Forum |
| Volume | 225-227 |
| Issue number | PART 1 |
| Publication status | Published - 1 Dec 1996 |
Keywords
- B2 Alloys
- Ball-Milling
- Differential Scanning Calorimetry
- Iron-Aluminides
- Nanocrystalline Phases
- Order-Disorder Transformation
- Thermogravimetric Magnetic Measurements
- X-Ray Diffraction