【作者】 冀国栋；

【导师】 景晓燕；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2009， 硕士

【摘要】 论文采用实验研究和理论分析相结合的方法,有针对性地研究了含稀土元素Mg-6Li-1.5A1系合金和不同含量Nd元素Mg-11 Li-1Al系合金。通过金相和扫描电镜观察、电子万能拉伸、X射线衍射分析、能谱分析等手段,探讨了稀土元素对镁锂合金组织性能的影响规律和作用机制。研究结果表明：(1)在Mg-11Li-1Al系合金中,加入少量Nd元素,可以细化组织,合金硬度增大,Nd含量在1.3%时,细化效果最佳,硬度最高。少量Nd的加入细化组织的作用机制是产生成分过冷效应和生成的AI11Nd3相颗粒阻碍晶粒的生长。(2)在Mg-6Li-1.5Al系合金中,加入1%不同稀土元素,合金的组织较Mg-6Li-1.5Al合金均有所细化,富La混合稀土和Nd的细化效果较好。稀土元素在合金中主要与Al形成金属间化合物,加入Ce的形成了Al2Ce；加入Y的形成Al2Y；加入Gd的形成AlGd;加入富La混合稀土的主要形成Al3La；加入Nd的形成Al2Nd.添加稀土元素,铸态合金抗拉强度和延伸率均有所提高。加入1%不同稀土元素,均可改善合金加工性能,经过变形加工后,组织明显细化,可显著提高抗拉强度,其强化机制以细晶强化为主。更多还原

【Abstract】 Mg-6Li-1.5Al based alloys with different rare earth and Mg-11Li-1Al based alloys with different content of Nd have been investigated in this paper. The effect of different rare earth on microstructure and properties of Mg-11Li-1Al alloy and the effect of Nd addition on microstructure and properties of Mg-11Li-1Al alloy was analyzed by OM, SEM, EDS, X-Ray and tensile tests. The results indicate that the addition of Nd in Mg-11Li-1Al alloy refined the microstructure and improved the hardness of alloys, and the best microstructure and the highest hardness were obtained when the content of Nd was 1.3%. The mechanism of refining is component super-cooling of Nd and the interception of Al11Nd3 particulate when the grains grow. Mg-6Li-1.5Al series alloys with 1% different species rare earth has refiner microstructure than Mg-6Li-1.5Al alloy especially when RE was La-rich misch metal or Nd. Rare esrch elements in alloys form compounds with mainly,such as Al2Ce, Al2Y, AlGd, Al3La,Al2Nd. The addition of rare earth can improve both the strength and ductility of Mg-6Li-1.5Al alloy. After extrusion, the microstucture is refined, the tensile strength increase obviously. The fine-grained strengthening is the main strengthening mechanism of Mg-6Li-1.5Al-1RE alloy.更多还原