In situ alloying of elemental Al-Cu12 feedstock using selective laser melting

Abstract

This investigation developed selective laser melting (SLM) processing parameters for the in situ fabrication of an Al-Cu12 alloy from pure elemental blends of aluminium and copper powders. Use of elevated pre-heat temperatures (400°C) created a coarser dendritic cell microstructure consisting of supersaturated Al-rich with a uniform Al2Cu phase granular microstructure compared to non-pre-heated samples. Al-Cu12 in situ samples achieved maximum tensile strength values comparable to that of sand cast pre-alloyed Al-Cu12. Processing at elevated pre-heat temperatures created components with higher ultimate tensile strength and ductility compared to standard room temperature-built samples due to it assisting a more complete melting of Al and Cu particles. Additionally pre-heating enabled an artificial age hardening, producing an equilibrium α + θ microstructure. The creation of an alloy in situ through the use of elemental powder blends represents a low-cost and flexible methodology for exploration of new SLM material compositions and potential candidate materials for semi-solid processing using SLM.

Keywords

• additive manufacturing
• selective laser melting
• in situ alloying