(1. 中南大学 材料科学与工程学院， 长沙 410083；
2. 悉尼大学澳大利亚微观分析国家重点实验室， NSW 2006)
摘 要: 通过时效硬化曲线的测量及时效组织的透射电镜分析， 研究了微量钪对Al-Ag合金时效析出行为的影响。 研究结果表明： 在Al-Ag合金中添加0.2%Sc(质量分数)， 可增强合金350℃的时效硬化效果， 延长达到峰时效的时间。微观组织分析发现， 微量钪的添加促使合金中γ′相弥散细小地析出， 同时钪的存在减少了γ′相宽面上的位错台阶数。 含钪Al-15Ag合金中γ′相长大过程比较缓慢的微观机理是微量钪的添加影响了合金中γ′相宽面上的台阶分布。
关键字: 铝合金; 时效; 微观组织; 钪
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Australian Key Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia）
Abstract:The age hardening behaviour and microstructure of Al-Ag-(0.2Sc) alloys were investigated. The results indicate that small addition of Sc can enhance the age hardening response of the Al-Ag alloy and prolong the time taken to the ageing peak. TEM observations show that the small addition of Sc results in a refinement of the distribution of γ′ precipitates. The mechanism by which trace Sc affect the microstructure is to reduce the ledge density of γ′ precipitates.
Key words: aluminium alloys; ageing; precipitation; scandium
