快凝Al-Ti-RE合金化合物相结构及形成的研究

Study on Microstructure and Formation of Intermetallic Compound in RS Al-Ti-RE Alloy

利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE),金刚石立方结构,该化合物相形成孪晶,其孪晶面{111},孪晶方向[112],认为化合物相是以孪晶为晶核从熔体中优先其他化合物相形成并生长.

Rapid solidification technology can produce fine, uniform dispersed intermetallic phase, with high strength, high hardness and good thermal stability of Altransition metal system alloy,which can be designed for elevated application. After detailed study on microstructure of RS AlTiLa alloy and the alloy after annealing in high temperature, the paper analyzes the thermal stability of intermetallic phase, and puts forward a new theory of intermetallic phase formation, which can be an important complement for others. The paper conclude that, intermetallic compound Al20Ti2La, which is fine, uniform dispersion with promise of good thermal stability, can be formed in RS Al-Ti-La alloy. It is supposed that the intermetallic phase is formed prior to others, and twin crystal formation is vital in nucleation stage.