Details

Autor(en) / Beteiligte

• LAY, M. D. H
• HILL, A. J
• SAKSIDA, P. G
• GIBSON, M. A
• BASTOW, T. J

Titel

27Al NMR measurement of fcc Al configurations in as-quenched Al85Ni11Y4 metallic glass and crystallization kinetics of Al nanocrystals

Ist Teil von

• Acta materialia, 2012, Vol.60 (1), p.79-88

Ort / Verlag

Kidlington: Elsevier

Erscheinungsjahr

2012

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The crystallization of melt spun Al85Ni11Y4 ribbon has been studied through systematic heat treatment in the 200-550 degree C temperature range using the techniques of nuclear magnetic resonance (NMR) spectroscopy, electrical resistivity, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). 27Al NMR spectroscopy provides a direct and sensitive method for determining the atomic fraction of alpha -Al and analysis of the alpha -Al crystallization kinetics. NMR results revealed low concentrations (3.9at.%) of alpha -Al configuration in the as-quenched material and confirm that they have alpha -Al short-range order. The ability of NMR to directly detect the alpha -Al configuration in the as-quenched state is compared and contrasted with XRD. Volume fractions of alpha -Al phase calculated from NMR are also compared and contrasted with that calculated from XRD for samples subjected to isothermal annealing. Qualitative and quantitative agreement between the two techniques is found after the XRD fractions are corrected according to literature methods. Heat treatment at moderate temperatures (200 degree C) is shown to result in transformation kinetics dominated by the growth of alpha -Al consistent with heterogeneous nucleation, while higher temperatures (300 degree C) lead to kinetics consistent with growth from homogeneous nucleation sites.