新型轻质TiAlBeSc系合金的组织及性能

Microstructure and Performance of TiAlBeSc Alloys with Low Density

摘要:

采用真空电弧炉熔炼制备新型轻质TiAlBeSc系合金，最小密度为3.289 g/cm3，利用SEM (EDS)、XRD、纳米力学探针和DTA等分析方法对合金的显微组织和热稳定性进行分析研究。结果表明，TiAlBeSc系合金形成稳定的金属间化合物和固溶体，1000 ℃以下加热过程中不发生相变，熔点均高于1100 ℃，具有很高的热稳定性。合金元素等摩尔比配比时，25%铍（原子分数）全部固溶于钪的点阵晶格，L10正方有序结构的TiAl相呈树枝状均匀分布于α-Sc的基体上，硬度高达7330 MPa，具有良好的综合力学性能。

Abstract:

A new-type of low density TiAlBeSc alloy system was prepared by vacuum arc melting. The lowest density is 3.289 g/cm3. Its microstructures, thermal stability were studied using SEM (EDS), XRD, nanoindentation and DTA methods. The results show that the TiAlBeSc alloy system forms stable intermetallic compound and solid solution. No transformation occurs below 1000 °C. These alloys exhibit a very high thermal stability with a melting point above 1100 °C. For the equimolar TiAlBeSc alloy, 25% (atomic percentage) beryllium is totally dissolved in scandium lattice. The dendritic TiAl phase with L10 ordered structure is uniformly distributed in α-Sc matrix which exhibits excellent mechanical properties with hardness 7330 MPa.