LIQUID-METAL EXPULSION DURING LASER IRRADIATION

During laser assisted materials processing such as welding, cutting, drilling, or surface alloying, the processing conditions are adjusted to either achieve or avoid liquid metal expulsion. Currently, there is no theoretical model to determine, from fundamental principles, the operating conditions for the initiation of liquid metal expulsion during laser irradiation. Processing conditions necessary for the initiation of liquid metal expulsion during pulsed laser irradiation have been investigated experimentally and theoretically. Lead, titanium, and stainless steel samples were irradiated by single and multiple pulses of varying pulse durations to investigate conditions for liquid metal expulsion. It is demonstrated that using theoretically computed transient spatial temperature profiles, and by balancing surface tension and recoil forces, the conditions for the initiation of liquid metal expulsion can be determined.