Phonon- and phason-type spherical inclusions in icosahedral quasicrystals
Phonon- and phason-type spherical inclusions in icosahedral quasicrystals
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DOI：
10.1088/0953-8984/15/24/102
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
Jianbo Wang;L Mancini;Renhui Wang;J Gastaldi
中科院分区：
文献类型：
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作者：
Jianbo Wang;L Mancini;Renhui Wang;J Gastaldi
本文导出了二十面体准晶体中球形内含物引起的声子型和相子型弹性位移场的一阶近似解析表达式。得到的声子型分量与传统的弹性各向同性晶体中球形夹杂的声子型分量相同，而相位型位移的表达式则首次得到，随着距离r的增加而减小，为r−1。讨论了三个具体案例。利用解析表达式中的声子部分模拟了AlPdMn iqc孔周围应变场的x射线形貌（XRT）图像中的黑白双瓣对比。采用相位型位移解析表达式，模拟了具有同构结构的球形夹杂周围应变场的XRT图像。实验图像和模拟图像之间惊人的相似性表明，这些内含物被具有相位型位移矢量的反相边界所包围，是iqc中特殊的结构缺陷。
Analytical expressions are derived as a first-order approximation for the elastic displacement fields, including both phonon- and phason-type components, induced by spherical inclusions in icosahedral quasicrystals (IQCs). The phonon-type component obtained is the same as that for a spherical inclusion in conventional elastically isotropic crystals, while the expression for the phason-type displacement, which decreases with increasing distance r to the sphere centre as r−1, is derived for the first time. Three concrete cases are discussed. The phonon part of the analytical expressions has been used to simulate the black–white double-lobe contrasts in the x-ray topograph (XRT) images of the strain field around the pores in the AlPdMn IQCs. The analytical expression for the phason-type displacement is used to simulate the XRT images of the strain field around spherical inclusions having isomorphic structures. The striking resemblance between experimental and simulated images suggests that such inclusions are surrounded by antiphase boundaries with a phason-type displacement vector, being particular structural defects in IQCs.