Slip deformation and melt threshold in laser-pulse-irradiated Al

We have examined pulse laser-irradiated 〈110〉 Al single crystals near the threshold energy for melting by ion channeling and electron microscopy. We find that slip deformation occurs at incident energies <3.5 J/cm2, where melting does not occur for our 20 nsec (full width at half maximum) pulse width, as well as at energies ≳3.5J/cm2, where a near-surface layer is melted. This slip deformation results in an increase in the channeling minimum yield χmin, which is attributed to small-angle misalignments between slip planes across the surface. The abrupt increase in χmin with melting suggests that channeling can provide a sensitive monitor of the threshold for melting.