Additive Manufacturing of Advanced Aluminum-Cerium Alloys

Aluminum alloys are ubiquitous in light-weighting applications due to an excellent combination of high specific-strength and corrosion resistance, but often face challenges at the highest performance levels, where more costly and denser materials are needed, such as Ti-alloys. Here we discuss fabrication of highly stable, intrinsically nanocrystalline Al-based powders that provide exceptional precipitate strengthening via powder production and subsequent fabrication of these powders using laser powder bed fusion and powder consolidation techniques. Additive manufacturing synthesis routes permit the production of structures otherwise impossible through conventional bulk processing routes. Al-Ce alloys exhibit an excellent combination of thermal stability, and high-temperature strength. These alloys contain a high-volume fraction of Al₁₁Ce₃ intermetallic (>20 vol%) that resists coarsening at high-temperature due to the near zero (<10^-4%) solubility of Ce in solid Al. This extreme thermal stability enabled us to set up the nanostructure during gas atomization and preserve it during solidification. This paper discusses fabrication techniques and mechanical property tests at both room temperature and 300°C for an aluminum alloy containing 8 weight percent Ce and 10 weight percent Mg as well as beneficial uses for the course and fine byproducts of the powder making process.