Resumo

HERNANDEZ, O. et al. Comportamiento estructural de aleaciones AlNi fabricadas por colada y sometidas a molienda mecánica de alta energía. Superf. vacío [online]. 2013, vol.26, n.1, pp.18-21. ISSN 1665-3521.

Abstract In this paper, two intermetallic alloys with the nominal compositions Al-Ni25 and Al-Ni24 (at %) were prepared by gravity casting technique and then subjected to wet ball-milling process. These alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was noted that the as-cast samples consist of NiAl₃-hexagonal and Ni₂Al₃-orthorhombic intermetallic phases embedded into an aluminum matrix. The wet-ball milling process applied to prealloyed samples is more efficient to crystal size reduction in comparison to the dry-milling process. This is as result of hydrogen embrittlement reaction that takes place into the mill to produce bayerite phase Al(OH)₃ and hydrogen gas. The amount of the bayerite phase increases with the increase of milling time. This result also suggests an increased in the amount of hydrogen released. Metallic phases are surrounded by bayerite phase which can passivity the hydrogen generation.

Palavras-chave : Hydrogen; Intermetallics; Mechanical milling; Structural characterization.