Structural evolution of B2-NiAl synthesized by high-energy ball milling

• Published in: Journal of materials science 2013, Vol.48 (1), p.265-272
• Main Authors: Ruiz-Luna, H., Alvarado-Orozco, J. M., Cáceres-Díaz, L. A., López-Báez, I., Moreno-Palmerín, J., Espinoza-Beltrán, F. J., Boldrick, M. S., Trápaga-Martínez, G., Muñoz-Saldaña, J.
• Format: Article
• Language: English
• Subjects: Alloying elements; Aluminum; Analysis; Ball milling; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallites; Crystallography and Scattering Methods; Differential scanning calorimetry; Evolution; Intermetallic compounds; Intermetallic phases; Intermetallics; Materials Science; Mechanical alloying; Microstrain; Nickel aluminides; Nickel base alloys; Nickel compounds; Nucleation; Phase transformations; Phase transitions; Polymer Sciences; Solid Mechanics; Synthesis; Transformation temperature; Transformations
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-012-6741-3

Structural evolution during the synthesis of B2–NiAl intermetallic compound by mechanical alloying of equiatomic elemental mixtures was studied by Rietveld analysis, DSC and HTXRD. The lattice parameter, crystallite size, microstrain, amount of phase and ordering of the B2 phase were monitored as a function of milling time. Formation of the B2–NiAl phase shows a sigmoidal behavior, which suggests that Johnson–Mehl–Avrami nucleation and interface-controlled growth are the responsible mechanisms in the transformation. Almost complete transformation (~ 97 mol%) was obtained after 25 h of milling. A specific phase transformation sequence during milling was not absolutely determined, however, the sequence Ni + Al → NiAl 3  → Ni 2 Al 3  → B2–NiAl was identified by HTXRD. This sequence was confirmed by DSC. The transformation temperature of the B2–NiAl phase and the presence of additional intermetallic compounds show a direct dependence on the Ni–Al layer spacing. Using a production-scale Simoloyer horizontal Attritor Mill, the presence of Ni 2 Al 3 phase was observed prior to the full synthesis of B2-NiAl.