含钪Al-Cu合金的显微组织

来源期刊：中国有色金属学报2005年第6期

论文作者：毛建伟 金头男 徐国富

文章页码：923 - 928

关键词：稀土; 钪; 显微组织; Al-Cu合金; 细化作用

Key words：rare earth; scandium; microstructure; Al-Cu alloy; refinement

摘    要：采用硬度测试、 金相观察、 扫描电镜和透射电镜测试及能谱分析的方法， 研究了稀土元素Sc含量对Al-4Cu合金组织的影响。 结果表明： Sc可显著细化Al-Cu合金的网胞组织， 减小枝晶间距， 细化合金的晶粒组织，提高合金的显微硬度， 提高幅度最约70%； 将Sc添加到Al-4Cu合金中， 当w(Sc)≈0.3%时， Sc除部分固溶于基体外， 大部分与Al形成Al-3Sc相, 其与基体的共格或半共格界面促进了θ′(CuAl₂)的析出； 当w(Sc)>0.3%时， Sc除部分固溶和形成Al₃Sc外， 还与Al、 Cu元素作用形成W(AlCuSc)相，降低Cu在α(Al)中的固溶度， 减少Al₂Cu(θ′)相的生成， 从而降低了合金的性能。

Abstract: The effects of different contents of rare earth Sc on the microstructures of Al-4Cu alloy by means of hardness measurement, optical microscopy(OM), scanning electron microscopy(SEM), transmitting electron microscopy(TEM) and energy spectrum analysis. The results show that the network structures of Al-Cu alloys can be remarkably refined, the distance of dendritic structure decreases, the structure of the alloy can be refined and the micro-hardness can be enhanced 70% or so. With additions of trace Sc to Al-Cu alloy, when the mass fraction of Sc is not more than 0.3%, Sc mostly， besides of a part of Sc existing in α(Al) solid solution， forms Al₃Sc phase with Al. When the amount is up to 0.5%, apart from the above-mentioned, Sc can interact with Al and Cu to form W(AlCuSc) phase， resulting in decrement of solid solubility of Cu in α(Al) solid solution and the amount of CuAl₂(θ′) phases, reducing the properties of alloy.