Microstructure, Hardening, and Mechanical Properties of Hypoeutectic Al-Ce-Ni Alloys with Zr and Zr plus Sc Additions and the Effect of Ultrasonic Melt Processing

Ternary Al-Ce-Ni alloys have a potential in the manufacture of automotive and airspace components, as well as in replacing traditional aluminum alloys in high-temperature applications, which is determined by the formation of fine and thermally stable Al11Ce3 and Al3Ni eutectic. Herein, the microstructure and mechanical properties of a hypoeutectic Al4Ce2Ni alloy using Zr and Zr+Sc additions combined with ultrasonic melt processing and dispersion hardening are improved. As a result, the grain structure of the as-cast alloys is significantly refined and the annealing at 350 degrees C leads to a considerable hardening effect, especially in the alloys with Zr+Sc additions (doubling the hardness). Al3Zr and Al-3(Zr,Sc) coherent particles are identified as hardening nanoprecipitates. The compressive mechanical testing at room and elevated temperatures shows that the additions of Zr and Zr+Sc improve the strength with the additional increase caused by ultrasonic melt processing.