Preparation of Large Grained Al 64 Cu 23 Fe 13 Icosahedral Quasicrystal Directly from the Melt
Preparation of Large Grained Al 64 Cu 23 Fe 13 Icosahedral Quasicrystal Directly from the Melt
复制标题
熔体直接制备大晶粒Al 64 Cu 23 Fe 13 二十面体准晶
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
H. Sunada
中科院分区：
文献类型：
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作者：
Y. Yokoyama;K. Fukaura;H. Sunada
研究了Al-Cu-Fe合金体系中包括二十面体(I-)相在内的各种相图，揭示了Al Cu23Fe13I相液相的平衡成分。I相是通过液体与初生λ2晶体之间的包晶反应形成的。防止包晶反应是产生单个准晶所必需的，然而，熔化的合金有很小的成分区域，可以将I相晶化为初晶。在Al60Cu37Fe3合金的常规凝固过程中，大部分初晶颗粒为I相，其余为λ2相。λ_2-粒子是I-准晶生长的非均匀晶位。为此，人们尝试了几种冶金处理方法来防止λ-2结晶。结果发现，Al59Cu37Fe3Si1熔体合金在978K时可以将Al-Cu23Fe13I相作为初晶晶化，应对Al59Cu37Fe3Si1熔体进行预循环熔炼处理，以防止λ-2晶化。并成功地从合金熔体中直接生长出了粗晶Al--Cu23Fe13I准晶。
Various phase diagrams including an icosahedral (i-) phase in Al-Cu-Fe alloy system were examined in order to reveal the composition of the liquid in equilibrium with the Al 64 Cu 23 Fe 13 i-phase. The i-phase was formed through the peritectic reaction between the liquid and the primary λ 2 -crystal. Prevention of the peritectic reaction was necessary to produce a single quasicrystal, however, there was a little compositional area of the molten alloy, which can crystallize the i-phase as a primary crystal. In the conventional solidification of Al 60 Cu 37 Fe 3 alloy, almost primary crystalline particles were classified as i-phase, and the rests were λ 2 -phase. The λ 2 -particles acted as the inhomogeneous crystallization sites of an i-quasicrystal growth. So, several metallurgical treatments were tried to prevent the λ 2 -crystallization. Consequently, we found out an Al 59 Cu 37 Fe 3 Si 1 molten alloy, which can crystallize the Al 64 Cu 23 Fe 13 i-phase as a primary crystal at 978 K. The Al 59 Cu 37 Fe 3 Si 1 molten alloy should be treated the preliminary cyclic melting process to prevent the λ 2 -crystallization. And we succeeded to grow up the large grained Al 64 Cu 23 Fe 13 i-quasicrystal directly from the molten alloy.