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

Abstract

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 ºC and 400 ºC, 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 °C, the adoption of low-cost and stable eutectic engineering reduces the economic barriers to additive manufacturing applications.