An additively manufactured heat-resistant Al-12Si alloy via introducing stable eutectic engineering

The poor microstructural stability of crack-free Al alloys synthesized via additive manufacturing typically possesses poor heat resistance. In this work, a novel heat-resistant Al-12Si-1.5Ni-2.0Fe (wt%) alloy was fabricated by additive manufacturing, in which tensile strength reaches 271 MPa and 98.1 MPa at 300 degrees C and 400 degrees C, respectively. Calculation and electron microscopy characterizations show that Fe/Ni segregation with high partition coefficients and low diffusion rates delivers a high thermally stability, thus providing a robust pinning force to inhibit the broken-up of Si eutectics and a solid barrier for dislocation motion at elevated temperatures. In addition to providing weight reduction by substituting Steel, Ti, and Ni-based alloys at 200-450 degrees C, the adoption of low-cost and stable eutectic engineering reduces the economic barriers to additive manufacturing applications.