摘要：微合金化是高性能铝合金发展的重要方向，其相关机理研究是目前铝合金领域关注的焦点。本文以Al-Cu合金作为模型材料，对比研究了微量元素Sc和Sn的微合金化作用，及其对材料强度、延性和断裂行为的影响。研究结果表明，Sc在Al-Cu合金中的微合金化作用机理为Sc原子在Al2Cu析出相界面的偏聚，通过降低界面能抑制了析出相长大，大幅度提高了材料的强度，并在一定范围内改善了材料的变形行为；Sn的微合金化作用机理为Sn颗粒诱发了Al2Cu析出相的异质形核，提高了形核密度，促进了析出相的弥散分布。通过微观结构的观察与统计，对材料的强韧化与变形断裂行为进行了分析和讨论。

　　关键词：铝合金；强韧化；变形断裂；微合金化

Strengthening and deformation behaviors of microalloyed aluminum alloys

Gang Liu 1）， Jun Sun

State Key Laboratory for Mechanical Behaviors of Materials,Xi'an Jiaotong University, ShaanXi Xi'an 710049

　　Abstract:Microalloying is an important approach to develop high-performance aluminum alloys, and the microalloying mechanism is now extensively focused. In this paper, we study the microalloying effect of Sc and Sn on the strength, ductility, and fracture behaviors of Al-Cu alloy. Experimental results show that the addition of Sc significantly inhibit the precipitation growth and thus increase the strength of the Al-Cu alloy, for which the microalloying mechanism is Sc segregation at the precipitate/matrix interfaces. While the Sn microalloying mechanism is that the Sn particles promote the heterogeneous precipitation of Al2Cu strengthening phases, increase the precipitate density, and enhance the dispersion of precipitates. Strenthening/toughening and deformation/fracture behaviors have been systematically analyzed with respect to the microstructural evolution caused by the microalloying effect.

　　Key words:Aluminum alloys; Strengthening and toughening; Deformation behaviors; Microalloying

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　　刘刚：lgsammer@mail.xjtu.edu.cn