脉冲电流对AI-Yb共晶合金组织及力学性能的影响

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Abstract：Al-Ybbinaryeutectic alloyswithvaryingYb contents（ 15% ， 21% ，and 29% ）wereprepared using the conventional casting method.The influence of diferent pulse current parameters on the eutectic structure of these allys were investigated through metallographic microscopy （OM），scanning electron microscopy （SEM），tensile mechanical properties testing，and microhardnesstesting. 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 characteristicof 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 rodsand rounded particles，resulting in material softening.The tensile strength decreases from 167MPa in the as-cast state to 143MPa afterpulsecurrent treatment，while the elongationincreasesfrom 4% to 7% ，matching theas-cast level.In practical applications，pulsed current processing proves to bean effective method to enhance the plastic deformation capacity of eutectic alloys.

Keywords：Al-Yb alloy; eutectic structure;pulse current;mechanical properties

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铝合金具有质轻、易成形、高比强度和高导热等特点，广泛应用于航空航天、交通运输、建筑和3C电子等现代工业[1-4]。（剩余8511字）