In laser surface remelting (LSR) treatment, only a small region is affected by heat, surpassing the melting temperature, followed by rapid cooling at 103–108 K/s, thus producing an extremely refined microstructure. The treated region shows a more homogeneous microstructure and better mechanical...

In laser surface remelting (LSR) treatment, only a small region is affected by heat, surpassing the melting temperature, followed by rapid cooling at 103–108 K/s, thus producing an extremely refined microstructure. The treated region shows a more homogeneous microstructure and better mechanical properties as compared to the substrate. Iron is a common impurity found in Al-based alloys but in the 2618 commercial alloy, around 1 wt.% of Fe is intentionally added to improve the high temperature strength and the corrosion resistance. In this work, LSR experiments were performed, by using a CO2 laser operating in a continuous-wave mode, to investigate the influence of process parameters on the treated surface of an as-cast Al-1 wt.% Fe alloy. These parameters encompass work distance (z), laser beam speed (v) and laser average power (P), setting a total of 18 combinations. The configuration of z = 6 mm, v = 500 mm/s and P = 800 W resulted in a molten pool with 710 µm of width for 242 µm of length without major porosities, therefore being the largest stable pool amongst all parameter combinations. The resulting cellular microstructure is shown to have an average interphase spacing of 0.93 ± 0.17 µm, a decrease of about 14 times in relation to that of the substrate. The effects of LSR on microhardness were remarkable, with the remelted track presenting Vickers microhardness of 50.1 ± 2 HV, which corresponds to increase of about 43% as compared to that of the original substrate

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES

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