Additive manufacturing using aluminum-containing wire

#The disclosed technology generally relates to consumable welding electrodes wires and more particularly to aluminum-containing consumable electrode wires, and to welding methods and systems adapted for using the aluminum-containing electrode wires.

#Various welding technologies, including traditional joining technologies as well as emerging additive manufacturing technologies, utilize welding wires that serves as a source of metal. For example, in metal arc welding, an electric arc is created when a voltage is applied between a consumable weld electrode wire, which serves as one electrode that advances towards a workpiece, and the workpiece, which serves as another electrode. The arc melts a tip of the metal wire, thereby producing droplets of the molten metal wire that deposit onto the workpiece to form a weld bead of a weldment or an article formed by additive manufacturing.

#Technological and economic demands on these welding technologies continue to grow in complexity. For example, the need for higher bead quality in both appearance and in mechanical properties continues to grow, including high yield strength, ductility and fracture toughness. Simultaneously, the higher bead quality is often demanded while maintaining economic feasibility. Some welding technologies aim to address these competing demands by improving the consumables, e.g. by improving the physical designs and/or compositions of the electrode wires.

#FIG. 1 is a schematic illustration of a configuration of electrodes in a metal arc welding process.

#FIG. 2A illustrates a metal arc welding system configured for a self-shielded flux-cored arc welding (FCAW-S), according to embodiments.

#FIG. 2B illustrates a metal arc welding system configured for a gas-shielded flux-cored arc welding (FCAW-G), according to embodiments.

#Various technological and economic demands on welding technologies, including joining technologies as well as emerging additive manufacturing technologies, which are often competing demands, continue to grow in complexity. For example, higher bead quality in terms of both appearance and mechanical properties are often desired without incurring negative economic or productivity consequences, e.g. higher cost of raw material and/or welding. In particular, in steel-based welding, improving or satisfying competing characteristics of mechanical properties such as yield strength, ductility, corrosion resistance, resistance to hot cracking and fracture toughness, may be needed, while maintaining economic feasibility.

#Some welding technologies aim to address these competing demands by improving the consumables, e.g. by improving the physical designs and/or compositions of consumable electrode wires. As one example, some traditional consumable electrodes incorporate additives such as chromium (Cr) and nickel (Ni). Chromium and nickel addition to ferrous alloys can provide, e.g., oxidation resistance through the ability to form a protective oxide layer. However, high amounts of Cr and Ni may be undesirable from a cost point of view. In addition, while providing one advantage, some additives may be insufficient in satisfying other characteristics, e.g., competing characteristics, or may introduce undesirable consequences. For example, under some circumstances, while providing oxidation and corrosion resistance, relatively high amounts of Cr and Ni can promote an undesirable amount of body-centered cubic (BCC) ferrite in the resulting weldment, which may lead to undesirable mechanical properties, including lower fracture toughness.

#In various embodiments described herein, consumable electrode wires have a core-shell structure, where aluminum is present in particular amounts, e.g., in the core. The electrodes various satisfy competing weldment properties, such as corrosion resistance, resistance to hot cracking and high fracture toughness. In addition, when used in certain welding processes, e.g., flux-cored arc welding, the disclosed electrodes can provide a lower cost solution compared to traditional additives in steel-based welding wires. In the following, various embodiments of aluminum-containing wires and welding processes and systems employing the aluminum-containing wires are disclosed first, followed by methods and systems for additive manufacturing using the aluminum-containing wires. However, it will be understood that the disclosed wires as well as various aspects of systems and methods can be used interchangeably in either or both joining and additive manufacturing technologies.