(1. 中南大学 材料科学与工程学院，长沙410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙410083；
3. 湖南省有色稀有金属材料科学与工程重点实验室，长沙 410083；
4. 国网辽宁省电力有限公司，沈阳 110042)
摘 要: 采用金相显微镜(OM)、扫描电镜(SEM)、电子探针(EPMA)、透射电镜(TEM)和扫透电镜(STEM)以及硬度、电导率和拉伸性能测试等方法研究微量Si元素对Al-Zr-Sc-Er合金组织和性能的影响。结果表明：添加Si元素能够促进富Er初生相的形成，增加铸态合金硬度，但会显著降低电导率；在Al-Zr-Sc-Er合金中，经适当热处理可形成核-双壳结构的Al3(Er,Sc,Zr)复合相，添加Si能够增大合金时效响应速度，促进Zr、Sc、Er析出，并参与第二相形核，形成(Al,Si)3(Er,Sc,Zr)相。相较于未添加Si的合金，添加0.05% Si的合金经(300 ℃, 24 h)+(400 ℃, 48 h)双级时效后硬度和电导率均提高，但Si的添加会导致析出相粗化，从而降低合金的再结晶温度。
关键字: Al-Zr-Sc-Er合金；Si元素；显微组织；电导率；硬度
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;
3. Key Laboratory of Nonferrous and Rare Metal Materials Science and Engineering, Changsha 410083, China;
4. State Grid Liaoning Electric Power Supply Co., Ltd., Shenyang 110042, China）
Abstract:The effects of trace Si on microstructure and properties of dilute Al-Zr-Sc-Er alloys were investigated by OM, SEM, EPMA, TEM, STEM, hardness tests, electrical conductivity tests and tensile tests systematically. The results show that the addition of Si promotes to form more Er-rich primary phases in as-cast alloys, which enhances hardness but obviously decreases electrical conductivity of as-cast alloys. Core-double shell structureAl3(Er,Sc,Zr) precipitated with proper heat treatment in Al-Zr-Sc-Er alloys. Si increases the ageing response speed of the alloy, promotes the precipitation of Zr, Sc, Er elements. Si can participate in the nucleation of the (Al,Si)3(Er,Sc,Er) phase. After a two-stage aging treatment (300 ℃, 24 h+400 ℃, 48 h), the hardness and electrical conductivity of alloys with 0.05% Si addition is higher than with no Si addition alloys. However, the addition of Si causes coarsening of the precipitated phase, thereby reducing the recrystallization temperature of the alloy.
Key words: Al-Zr-Sc-Er alloys; Si element; microstructure; electrical conductivity; hardness
