Phase field simulation of kinetic superheating and melting of aluminum nanolayer irradiated by pico- and femtosecond laser

Two melting mechanisms are reproduced and quantified for superheating and melting of Al nanolayer irradiated by picoand femtosecond laser using the advanced phase-field approach coupled with mechanics and a two-temperature model. At heating rates Q 79:04 K/ps induced by picosecond laser, two-sided barrierless surface melting forms two solid-melt interfaces, which meet near the center of a sample. The temperature for surface melting is a linear function, and for complete melting it is a cubic function, of logQ. At Q 300 K/ps induced by femtosecond laser, barrierless and homogeneous melting (without nucleation) at the sample center occurs faster than due to interface propagation. Good agreement with experimental melting time was achieved in a range of 0:95 Q 1290 K=ps without fitting of material parameters. VC 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4858395]