Effect of pulse current on microstructure and mechanical properties of Al-Yb eutectic alloy

Al-Yb binary eutectic alloys with varying Yb contents (15%, 21%, and 29%) were prepared using the conventional casting method. The influence of different pulse current parameters on the eutectic structure of these alloys were investigated through metallographic microscopy (OM), scanning electron microscopy (SEM), tensile mechanical properties testing, and microhardness testing. The reasons for the changes in the microstructure and properties of the alloy were thoroughly analyzed. The results indicate that the microstructures of Al-15Yb, Al-21Yb, and Al-29Yb are characteristic of hypoeutectic, complete eutectic, and hypereutectic compositions, respectively. The eutectic region of Al-15Yb exhibits a finely lamellar structure with an interlamellar spacing of 100–200nm. Following pulsed current treatment, the lamellar structure of Al-21Yb transforms into short rods and rounded particles, resulting in material softening. The tensile strength decreases from 167MPa in the as-cast state to 143MPa after treatment, while the elongation increases from 4% to 7%, matching the as-cast level. In practical applications, pulsed current processing proves to be an effective method to enhance the subsequent deformability of the eutectic alloy.