Over the past decade,the cast aluminum alloys with excellent mechanical and conductivity properties have emerged as potential materials for thermal management.However,the traditional Al-Si based alloys are difficult to make significant breakthrough in conductivity performance.The hypoeutectic Al-5Ni alloy also possesses sound castability and is expected to be applied in thermal management applications.In this study,the effects of ytterbium(Yb element)at 0-0.5 wt％on the microstructures as well as the electrical/thermal conductivity and mechanical properties of the Al-5Ni alloy were sys-tematically investigated.The experimental results indicate that the addition of Yb at a relatively low amount not only reduces the secondary dendrite arm spacing of the α-Al grains,but also modifies the morphology and distribution of eutectic boundary phase.Moreover,it is found that the dosage of Yb at 0.3 wt％in the Al-5Ni alloy can simultaneously improve the yield strength,ultimate tensile strength and electrical/thermal conductivity.The strengthening and toughening of the Al-5Ni alloy are mainly attributed to the decrease of secondary dendrite arm spacing and the improvement of eutectic phases.The transmission electron microscopy/selected area electron diffraction(TEM/SAED)analysis indicates that the ytterbium in Al-5Ni alloy will form Al3Yb phase,which mainly agglomerates in the Al3Ni phase region.This phase is helpful to decrease the solubility of impurity elements(e.g.,Fe and Si)in the α-Al matrix,which is beneficial to electrical/thermal conductivity.The value of this study lays foundation for manufacturing Al-Ni alloys with high thermal conductivity and acceptable mechanical properties.

Kang Wang;Shaodong Hu;Yanglin Zhong;Shuoxun Jin;Zirong Zhou;Zhiyu Wang;Jiongcai Chen;Bingbing Wan;Wenfang Li

School of Materials Science and Engineering,Dongguan University of Technology,Dongguan 523808,China;Institute of Science and Technology Innovation,Dongguan University of Technology,Dongguan 523808,China

稀土学报（英文版）

[1]Kang Wang;Shaodong Hu;Yanglin Zhong;Shuoxun Jin;Zirong Zhou;Zhiyu Wang;Jiongcai Chen;Bingbing Wan;Wenfang Li-.Effects of trace ytterbium addition on microstructure,mechanical and thermal properties of hypoeutectic Al-5Ni alloy)[J].稀土学报（英文版）,2022(08):1305-1315

Al3Yb

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