稀土对铝钛硼中间合金组织及细化性能的影响

Effect of rare earths on the microstructure and refining of Al-Ti-B master alloys

采用氟盐铝热反应法制取不同稀土含量的Al-Ti-B-RE中间合金,并对其微观组织和细化效果进行了分析,讨论了稀土元素对Al5Ti1B组织及性能的影响。X射线衍射及能谱分析证明:稀土元素和TiAl3结合生成了Ti2Al20RE,同时TiAl3尺寸减小、数量减少;TiB2尺寸、形态不受影响,但分布更加均匀弥散。细化效果试验表明稀土元素确实可以提高Al5Ti1B中间合金的细化效果。在5Ti1B系Al-Ti-B-RE中间合金中,稀土元素的最佳质量分数为3.53%,此时能取得最理想的微观组织和细化效果。

A1-Ti-B-RE master alloys were prepared by reacting complex halide salts with molten aluminum and rare earth elements at high temperatures to investigate the effect of rare earths on the microstructure and refining of the alloys. The results show that TiAl3 reacts with the rare earths to form Ti2Al20RE. The quantity and size of the TiAl3 particles decrease because of increases of the new phases while the distribution of TiB2 is more homogeneous with the size and shape unchanged. Rare earths can improve the refining performance of Al5TilB, and the optimum rare earth mass fraction of Al-Ti-B-RE with 5% Ti and 1% B is 3. 53% which gives the ideal microstructure and the best refining performance.