Zr-4合金中氢化物析出的TEM研究

TEM Study of Zirconium Hydrides Precipitated in Zr-4 Alloy

摘要:

利用透射电镜（TEM）研究了Zr-4合金吸氢后析出氢化物的类型、形貌及其位相关系。结果表明，随着吸氢量的增加，Zr-4合金中依次析出了δ-ZrH1.6及ε-ZrH1.8氢化物。δ氢化物主要以板条状从α-Zr 基体上析出，二者的取向关系为：(0001)α//(001)δ，[2 0]α //[110]δ。 ε氢化物以针状形貌从δ氢化物中析出，析出的ε氢化物的密排面( 1 )与δ氢化物的密排面( 1 )平行，二者的取向关系为：( 1 )δ //( 1 )ε，[ 12] δ//[011]ε。高分辨观察进一步表明，δ-ZrH1.6及ε-ZrH1.8氢化物的晶格点阵均出现了严重的扭曲变形，说明相变存在较大的应力集中。

Abstract:

The type, morphology and orientation relationship of the hydride precipitates in a hydrogen absorbed Zr-4 alloy have been studied by means of transmission electron microscopy (TEM). The results show that δ-ZrH1.6 and ε-ZrH1.8 hydrides are found to precipitate successively with the increase of hydrogen absorption. For the δ-ZrH1.6 hydrides, they are mainly in the form of lath and precipitate in the orientation relationship of (0001)α//(001)δ and [2 0]α //[110]δ with the α-Zr matrix, while for the ε-ZrH1.8 hydrides, they are in acicular morphology and precipitate in the orientation relationship of ( 1 )δ //( 1 )ε and [ 12] δ//[011]ε with the δ-ZrH1.6 hydrides. The close-packed planes of these two hydrides are identified to be parallel. High-resolution TEM observation shows that there exists a great deal of distortion inside the crystal lattice of the δ-ZrH1.6 and ε-ZrH1.8 hydrides, indicating a large stress concentration produced during their precipitation.