Lamellar instabilities during scanning laser melting of Al–Cu eutectic and hypoeutectic thin films

نویسندگان

چکیده

Scanning laser melting was employed to investigate directional solidification in Al–Cu thin films, 200 and 500 nm thick. The alloy with both eutectic hypoeutectic compositions, were co-deposited on fused silica substrates by magnetron sputtering. Melting of the films carried out air using a CW laser, as function scan velocity, v, up 5 cm/s. For regular lamellar microstructure observed over entire range velocities studied. Interlamellar spacings, λ, below 50 readily produced. Results found be consistent studies bulk alloys, obeying classic steady state growth relationship, λ2v = K. However, value constant, K is significantly larger when compared bulk. This attributed constraints mechanisms for spacing adjustment two-dimensional systems. In complex structure velocity reduced. Regions straight lamellae, oscillatory solitary tilt waves, recurring extreme branching events coexisted across melt track. Fourier analysis used quantify chaotic area fraction films. transition chaos occurred G/v ratio increased, approaching re-entrant eutectic-to-dendritic from above. Approaches further refine order better control processes are discussed.

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ژورنال

عنوان ژورنال: Journal of Alloys and Compounds

سال: 2021

ISSN: ['0925-8388', '1873-4669']

DOI: https://doi.org/10.1016/j.jallcom.2021.158800