(1. 西安交通大学 材料科学与工程学院, 金属材料强度国家重点实验室, 西安 710049;
2. 中南大学 粉末冶金国家重点实验室, 长沙 410083)
摘 要: 电导率的变化能够灵敏地反应Al-Mg-Si合金的时效析出过程，然而溶质原子及时效析出第二相对电导率的单独影响尚不清楚。Al-Mg-Si合金中含有3种成分和形貌不同的第二相。通过实验及模型化系统地研究Al-Mg-Si合金中多重析出第二相对其电导率的影响。结果表明：由于棒状β′′相或针状β′相能够分别在473和523 K时有效地阻碍传导电子的移动，因此Al-Mg-Si合金的电导率主要依赖于棒状β′′相(T=473 K)或针状β′相(T=523 K)的影响。模型预测结果与实验结果吻合良好，验证了模型的有效性。
关键字: Al-Mg-Si合金；多重析出；电导率
aged Al-Mg-Si alloys
（1. State Key Laboratory for Mechanical Behavior of Materials, School of Material Science & Engineering,
Xi’an Jiaotong University, Xi’an 710049, China;
2. State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The electrical conductivity measurement is a much sensitive tool for studying the precipitation in Al-Mg-Si alloys, but the single effects of solute atoms and fine scale precipitates on electrical conductivity are not clear. In this work, the systematic experiments and modeling were performed to study the effect of multiple precipitates on the electrical conductivity of aged Al-Mg-Si alloys that contain three kinds of precipitates with different compositions and morphologies. The results show that the electrical conductivity of the alloy exhibits the most sensitive to a dominant kind of precipitates, i.e., rod-shaped β′′ precipitates at 473 K and needle-shaped β′ precipitates at 523 K, respectively. This is because the two kinds of precipitates can form an effective barrier net to hinder the mass migration at 473 and 523 K, respectively. The good agreement between model and experiments indicates the validity of prediction.
Key words: Al-Mg-Si alloys; multiple precipitates; electrical conductivity
