An additively manufactured near-eutectic Al–Ce–Ni–Ti–Zr alloy: microstructure, mechanical properties and heat resistance

Nowadays, heat resistance of additively manufactured aluminum alloys is highly in demand to meet the high-temperature strength requirements for lightweight components. However, existing commercially-available alloys exhibit severe strength degradation at elevated temperatures due to coarsening of strengthening phases. In this study, an additively manufactured near-eutectic Al–Ce–Ni–Ti–Zr alloy with superior heat resistance was developed based on the thermodynamic calculations. The new alloy possesses good printability thanks to the combination of the near-eutectic Al–Ce–Ni composition and inoculation treatment provided by Ti and Zr micro-additions. The eutectic solidification microstructure comprises a high volume of coarsening-resistant Al11Ce3 and Al3Ni phases and presents a typical hierarchical microstructure where refined equiaxed grains decorates melt boundaries. Such microstructure characteristics determine excellent heat resistance and good mechanical properties at ambient and elevated temperatures with 400°C. The alloy possesses a yield strength of 427 MPa and an elongation of 4.7% at ambient temperature. Even at 400°C, the alloy still retains a superb tensile yield strength of 104 MPa and an elongation of 17.86%. This work provides an effective pathway for heat-resistant aluminum alloy design via additive manufacturing and other rapid solidification processes.