Characterization of the keyhole formed during pulsed Nd–YAG laser interaction with a Ti–6Al–4V metallic target

Abstract

We observed, with an x-ray apparatus, the keyhole formed during the interaction of a pulsed Nd–YAG laser beam with a metallic target of a Ti–6Al–4V titanium alloy. We noted that the keyhole formation is not instantaneous and that it grows linearly during the duration of the interaction. We highlighted that its depth, at the end of the laser pulse, is practically equal to the melting-zone depth in the material. Finally, we showed from the results of these tests that a quick estimation of the melting depth can be made simply from the ratio of the power densities used with a reference test.