Microstructure and Mechanical Properties of As-Cast Al-10Ce-3Mg-xZn Alloys.

The microstructure and mechanical properties of as-cast Al-10Ce-3Mg-xZn (x = 0, 1, 3, 5 wt.%) alloys were systematically investigated, with a focus on the effect of Zn on the AlCe reinforcing phase in the alloy. The results showed that the Al-10Ce-3Mg alloy consists of α-Al, a Chinese-script AlCe eutectic phase, and a massive AlCe primary phase. With the addition of Zn content, most of the Zn atoms are enriched in the AlCe phase to form the acicular-like AlCeZn phase within the AlCe phase. Increasing the Zn content can increase the volume fraction of the AlCe phase. Compared to the alloy without Zn addition, the microhardness and elastic modulus of the AlCeZn-reinforced AlCe phase in the alloy with 5 wt.% Zn increased by 18.9% and 9.0%, respectively. Moreover, the room-temperature mechanical properties of Al-10Ce-3Mg alloys were significantly improved due to the addition of Zn element. The alloy containing 5 wt.% Zn had the best tensile properties with an ultimate tensile strength of 210 MPa and a yield strength of 171MPa, which were 21% and 77% higher than those of the alloy without Zn, respectively. The alloy containing 5 wt.% Zn demonstrated a superior retention ratio of tensile strength at 200-300 °C, indicating that the alloy has excellent heat resistance. The improvement in the mechanical properties is primarily attributed to second-phase strengthening and solid solution strengthening.