Crystallization behavior of a gas atomized Al 85Ni 10La 5 amorphous alloy

• Published in: Journal of non-crystalline solids Vol. 351; no. 19; pp. 1646 - 1652
• Main Authors: Zhang, Zhihui, Witkin, David, Lavernia, Enrique J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2005
• Subjects: 61.46.+w; A180; C290; 64.70.Kb; 61.43.Dq
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2005.04.055

Al 85Ni 10La 5 (at.%) alloy powders were fabricated using gas atomization. X-ray diffraction analysis revealed that powders in the size range of <500 mesh (<25 μm) are amorphous. The crystallization behavior and kinetics of the amorphous Al 85Ni 10La 5 powders (<25 μm) were investigated during continuous heating and isothermal annealing. The amorphous Al 85Ni 10La 5 alloy undergoes a multi-step crystallization reaction in the temperature range of 250–390 °C. The activation energies for the first exothermic reactions were determined as 344 kJ/mol. Instead of a primary crystallization, a eutectic reaction was found to be associated with the first reactions and the crystalline phases were identified as fcc-Al, Al 11La 3, Al 3Ni and a metastable phase Al 3La. The isothermal annealing was carried out at temperatures of 235 °C, 245 °C and 250 °C. Results from the isothermal annealing analyses revealed presence of quenched-in Al nuclei. The influence of isothermal annealing on the thermal stability of the Al 85Ni 10La 5 powders (<25 μm) is also discussed.