Electrostatic stress-driven pull-up growth of molten titanium via laser irradiation

Abstract Electromagnetic forces are applied to control crystal growth in molten metals, typically via magnetic forces, because electrostatic energy is lower than magnetic energy. This study investigates the application of intense electrostatic energy to molten titanium (Ti) by heating a Ti wire’s tip with a laser in the presence of an electrostatic field, resulting in the formation of convex-molten Ti with a concentrated electrostatic field. When 15 kV was applied across the molten Ti, electric stress exceeding the surface tension pulled the melt upward, forming a sharp Ti tip whose apex was surrounded by facets. However, when 8 kV was applied, the melt’s surface tension was greater than the electrostatic stress; therefore, the melt could not grow upward, resulting in a rounded Ti tip. This study demonstrates that the electrostatic field applied during laser heating effectively controls melt growth, indicating the proposed method’s potential for precise material structuring.