Precipitation of the icosahedral quasicrystalline phase, R-phase and Laves phase in ferritic alloys
Precipitation of the icosahedral quasicrystalline phase, R-phase and Laves phase in ferritic alloys
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DOI：
10.2320/matertrans.45.357
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发表时间：
2004-02-01
影响因子：
1.2
通讯作者：
Mishima, Y
中科院分区：
文献类型：
--
作者：
Yamamoto, K;Kimura, Y;Mishima, Y
用透射电子显微镜研究了含和不含0.3at%Si的Fe-10Cr1.4W-4.5Co(at%)合金中金属间化合物相在铁素体中的析出行为。旨在为金属间化合物强化铁素体耐热合金的合金设计提供基础资料。在含硅的合金中，在873K时效过程中发现有二十面体准晶相(I相)析出，证实了析出物的选区衍射(SAD)花样具有两重、三重和五重对称性，并在与黄金分割相关的位置有衍射点。在无硅合金中，在873K时，R相代替I相析出，在973K的高温时效过程中，两种合金中都有Laves相的析出。在973K时形成的Laves相在含硅合金中转变为I相，而在随后的873K时效过程中，无硅合金中则转变为R相。通过比较I相与R相和Laves相的取向关系、析出形态和稳定性，发现二十面体准晶和晶态的R相和Laves相的结构非常相似。
Precipitation behavior of intermetallic phases in ferrite matrix is investigated by transmission electron microscopy (TEM) in Fe-10Cr-1.4W-4.5Co (at%) alloys with and without 0.3 at%Si. It is intended to provide basic information for the alloy design of ferritic heat resistant alloys strengthened by intermetallic compounds. In the alloy containing Si, icosahedral quasicrytalline phase (I-phase) is found to precipitate during aging at 873 K. It is confirmed that selected area diffraction (SAD) patterns of the precipitates exhibit two-, three- and five-fold symmetry and have diffraction spots in the positions related to the golden section. In the Si-free alloy, the R-phase precipitates instead of I-phase at 873 K, and the Laves phase precipitates in both alloys during aging at higher temperature, 973 K. The Laves phase formed at 973 K transforms to the I-phase in the alloy containing Si but to the R-phase in the Si-free alloy during subsequent aging at 873 K. It is found that the structures among icosahedral quasicrystalline and crystalline R- and Laves phases are closely similar by comparing the orientation relationship, precipitate morphology and stability of I-phase with those of R- and Laves phases.