MICROSTRUCTURE REFINEMENT METHODS BY MELT POOL STIRRING FOR ADDITIVE MANUFACTURED MATERIALS

摘要

To provide methods for refining the microstructure of a deposited layer of metallic material during additive manufacturing that can accommodate structures with various types of designs.SOLUTION: A method comprises generating a first layer by heating a metallic material to a molten state such that the metallic material includes a solid-liquid interface, and applying an electromagnetic field or vibrations to the metallic material of the first layer. The electromagnetic fields or vibrations creates perturbation in the first layer of metallic material thereby causing one or more nucleation sites to form at the solid-liquid interface of the metallic material in the molten state. The method also includes generating a second layer coupled to the first layer. Generating the second layer increases the number of nucleation sites at the solid-liquid interface of the metallic material in the molten state. Each nucleation site can grows a crystal at a spatially random orientation.SELECTED DRAWING: None