Grain refinement mechanism in advanced γ-TiAl boron-alloyed structural intermetallics: The direct observation
Grain refinement mechanism in advanced γ-TiAl boron-alloyed structural intermetallics: The direct observation
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DOI：
10.1016/j.matlet.2014.12.025
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发表时间：
2015-03
影响因子：
3
通讯作者：
A. Kartavykh;M. Gorshenkov;D. Podgorny
中科院分区：
文献类型：
--
作者：
A. Kartavykh;M. Gorshenkov;D. Podgorny
采用电子束半连续铸造技术从纯金属合成了 Ti-44Al-5Nb-2Cr-1.5Zr-0.4B-0.07La 和 Ti-44Al-5Nb-1Cr-1.5Zr-1B-0.17La (at%) 金属间化合物。合金具有复杂的微观结构，其细化随着硼含量的增加而逐渐细化。使用 SEM、EBSD 和 EDX 技术对样品进行分析。硼合金化导致凝固熔体中微维复合硼化物的沉淀。这些颗粒孕育剂促进更精细微观结构的形成。俄歇光谱法用于硼化物的定量元素分析。事实证明，结构细化的根源在于α2-Ti3Al相在(Ti,Nb)B带状菌落上固相萌发，随后α2-板条通过γ-TiAl基体生长。我们修复了微观结构细化过程的几个连续阶段。这些阶段的描述得到了微观结构成分的晶体学和成分表征的支持。这项工作为所研究材料的微观结构/机械性能工程提供了新的数据。
The synthesis of Ti–44Al–5Nb–2Cr–1.5Zr–0.4B–0.07La and Ti–44Al–5Nb–1Cr–1.5Zr–1B–0.17La (at%) intermetallics was performed from pure metals by the electron beam semi-continuous casting technique. Alloys possess the convoluted microstructure whose refinement is progressive with the boron content increase. The specimens were analyzed using SEM, EBSD and EDX techniques. The boron alloying causes precipitation of micro-dimensional complex borides within solidifying melt. These particles-inoculants promote the formation of finer microstructure.Augerspectrometry was applied for quantitative elemental analysis of borides. It was proven that the origin of structure refinement consists in solid-phase germination of α2-Ti3Al-phase on (Ti,Nb)B ribbon-like colonies with subsequent growth of α2-laths through γ-TiAl matrix. We fixed several consecutive stages of microstructure refinement process. The description of these stages is supported with the crystallographic and compositional characterization of microstructural constituents. The work provides new data for microstructure/mechanical properties engineering of studied materials.