Microstructural stability of a cast Ti-45.2Al-2W-0.6Si-0.7B alloy at temperatures 973-1073 K
Microstructural stability of a cast Ti-45.2Al-2W-0.6Si-0.7B alloy at temperatures 973-1073 K
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DOI：
10.1016/j.intermet.2005.12.013
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发表时间：
2006-01-01
期刊：
影响因子：
4.4
通讯作者：
Pelachova, T.
中科院分区：
文献类型：
--
作者：
Lapin, J.;Pelachova, T.
研究了Ti-45.2Al-2W-0.6Si-0.7B （at.%）合金在973 ~ 1073 K时效至10000 K时效后的显微组织稳定性。合金显微组织由层状区和富钛区组成。层状区由γ (TiAl)和α (2)（Ti3Al）相的细小层状组成，层状界面上有细小的B2和Ti5Si3相析出。细α(2)薄片在老化前部分分解。在片层区发现少量粗B2颗粒和少量带状硼化物。富钛区含有粗α(2)薄片、棒状B2颗粒、小体积分数的粗Ti5Si3析出物和带状硼化物。在973 ~ 1073 K的长期时效过程中，合金的接收组织是不稳定的。层状区和富钛区α(2)相转变为γ相，形成细针状B2相。微观组织的不稳定性导致合金的软化。与富钛区相比，片层区显微硬度的下降速度更快。(C) 2006 Elsevier Ltd版权所有。
Microstructural stability of a cast intermetallic Ti-45.2Al-2W-0.6Si-0.7B (at.%) alloy after ageing in the temperature range from 973 to 1073 K up to 10,000 It was studied. The microstructure of the alloy consists of lamellar and TiAl-rich regions. Lamellar regions consist of fine lamellae of gamma(TiAl) and alpha(2)(Ti3Al) phases, fine B2 and Ti5Si3 precipitates on the lamellar interfaces. Fine alpha(2) lamellae are partially decomposed before ageing. Small volume fraction of coarse B2 particles and few ribbon-like borides were found within lamellar regions. TiAl-rich regions contain coarse alpha(2) lamellae, rod-like B2 particles, small volume fraction of coarse Ti5Si3 precipitates and ribbon-like borides. The as-received microstructure of the alloy is unstable during long-term ageing at temperatures ranging from 973 to 1073 K. The alpha(2) phase in the lamellar and TiAl-rich regions transforms to the gamma phase and fine needle-like B2 precipitates. The microstructural instabilities lead to softening of the alloy. The microhardness decrease is measured to be faster in the lamellar regions compared to that in the TiAl-rich regions. (C) 2006 Elsevier Ltd. All rights reserved.