Effects of Solidification under Ultrasonic Vibrations on Al11Ce3 Phase Fragmentation and Mechanical Properties of Al-10 wt.% Ce Alloy

Al-Ce alloys are currently receiving attention due to their high-temperature properties. Ultrasonic treatment (UST) is a liquid metal processing method, through which the structure of light alloys is modified. In the present study, Al-10 wt.% Ce alloy is prepared by melting and solidification under ultrasonic vibrations. UST temperatures (645-665 °C) are decided using differential scanning calorimetry. This study investigates the morphology of orthorhombic Al₁₁Ce₃ compound as influenced by UST, and the corresponding effects on the strength and high-temperature wear properties. It was observed that the shearing behavior of ultrasonic waves fragmented the intermetallic compound. Instead of being coarse and connected lath-like phase, Al₁₁Ce₃ was changed to well-fragmented particles. The particle size of Al₁₁Ce₃ decreased from ~30 μm to ~3 μm, with UST at 655 °C and up to submicron. The area fraction of the intermetallic particles also increased from ~31 to ~40% after UST at the optimum temperature. The hardness of conventionally solidified alloy increased from ~42 to 50 Hv, and the ultimate compression strength increased from ~290 to 390 MPa, after UST at 655 °C. The fine and well-distributed intermetallic particles observed at the optimum UST temperature increased the wear resistance of the alloy at both RT and higher temperatures.