Heat resistant ultra-strong Al-Si alloy and its application in additive manufacturing

This study develops an Al-Si-Fe-Mn-Ni alloy featuring fine grains and stable grain boundaries to meet the stringent load-bearing requirements of additively manufactured components operating in high-temperature environments. By leveraging solid-solution and precipitation-strengthening mechanisms, we introduce Fe and Ni, two common transition-metal elements, to form high-density, thermally stable intermetallic compounds, which subsequently stabilize the grain boundary structure of the SLM-printed alloy. Mn addition further facilitates the precipitation of Al₆Mn strengthening phases. These synergistic strengthening mechanisms lead to exceptional mechanical performance, with the composites achieving a tensile strength of 556 MPa and elongation of 5.3% at 25°C and 372 MPa and 14.3% at 200°C. Furthermore, the ultimate compressive strength of the G-type TPMS scaffold fabricated from this Al-Si-Fe-Mn-Ni alloy exhibits a 144% increase at 25°C and 157% at 200°C compared to AlSi10Mg. This study proposes a straightforward, reliable, and cost-effective strategy for designing a high-performance Al-Si alloy, offering a promising pathway for enhancing mechanical reliability and expanding industrial applications in extreme environments.