Aluminum alloy powders for powder bed fusion additive manufacturing processes

An aluminum alloy powder for manufacturing a three-dimensional high thermal conductivity aluminum alloy part by a powder bed fusion additive manufacturing process, each particle of the aluminum alloy powder comprising:

• an aluminum alloy including, by weight:
• greater than 95% aluminum, and
• greater than 0% and less than 5% of at least one nucleating agent, and
• wherein the at least one nucleating agent comprises an element or compound having a solid solubility in aluminum of, by weight, less than 0.5% at temperatures less than 530 degrees Celsius,
• wherein, when the aluminum alloy is heated to a first temperature greater than a liquidus temperature of the aluminum alloy and subsequently cooled to a second temperature less than the liquidus temperature of the aluminum alloy and greater than a solidus temperature of the aluminum alloy, the alloy transitions from a liquid phase to a multiphase system, and
• wherein the multiphase system includes a solution of liquid phase aluminum and a solid phase of particles of the at least one nucleating agent dispersed throughout the liquid phase aluminum.

A method of manufacturing a three-dimensional aluminum alloy part, the method comprising:

• (a) providing an aluminum alloy powder feed material;
• (b) distributing a layer of the powder feed material over a substrate;
• (c) scanning selective regions of the layer of the powder feed material with a high-energy laser or electron beam to form a pool of molten aluminum alloy material therein, the selective regions of the layer of the powder feed material corresponding to a cross-section of an aluminum alloy part being formed;
• (d) terminating the laser or electron beam to cool and solidify the pool of molten aluminum alloy material into a solid layer of fused aluminum alloy material;
• and
• (e) sequentially repeating steps (b) through (d) to form an aluminum alloy part made up of a plurality of solid layers of fused aluminum alloy material,
• wherein, during solidification of the pool of molten aluminum alloy material, solid phase particles form within a solution of liquid phase aluminum prior to formation of solid phase aluminum dendrites, and
• wherein, each of the solid layers of fused aluminum alloy material in the aluminum alloy part includes a continuous aluminum matrix phase that exhibits a polycrystalline structure and predominantly includes a plurality of equiaxed grains.