Quantitative efficiency of optoacoustic ultrasonic treatment in SLM, DED, and LBW applications.

Ultrasound can improve the quality of finished products by reducing porosity and enhancing microstructure in selective laser melting, directed energy deposition, and laser beam welding. This study evaluates the efficiency of ultrasound produced by a pulsed laser via the optoacoustic effect. A quantitative model of collapse of vapor-gas bubbles has been developed under the conditions of ultrasonic treatment at near resonance frequencies.

Arrhenius Crossover Temperature of Glass-Forming Liquids Predicted by an Artificial Neural Network.

The Arrhenius crossover temperature, TA, corresponds to a thermodynamic state wherein the atomistic dynamics of a liquid becomes heterogeneous and cooperative; and the activation barrier of diffusion dynamics becomes temperature-dependent at temperatures below TA. The theoretical estimation of this temperature is difficult for some types of materials, especially silicates and borates. In these materials, self-diffusion as a function of the temperature is reproduced by the Arrhenius law, where the activation barrier practically independent on the temperature .

Effect of laser-induced ultrasound treatment on material structure in laser surface treatment for selective laser melting applications.

A new mechanism for controlling the microstructure of products in manufacturing processes based on selective laser melting is proposed. The mechanism relies on generation of high-intensity ultrasonic waves in the melt pool by complex intensity-modulated laser irradiation. The experimental study and numerical modeling suggest that this control mechanism is technically feasible and can be effectively integrated into the design of modern selective laser melting machines.