急冷Al-Cu-Cr合金中二十面体准晶-晶体相变的

急冷Al-Cu-Cr合金中二十面体准晶-晶体相变的原位TEM研究

王瑞萍，孙 威*，周铃铃

（北京工业大学固体微结构与性能研究所，北京 100124）

摘 要：利用透射电子显微镜原位加热技术研究了快速凝固Al₇₀Cu₁₀Cr₂₀合金中富Cr二十面体准晶的相变过程。结果表明，当加热温度达到700℃时，亚稳Al-Cu-Cr二十面体准晶相转变为具有体心立方结构的γ₁相，其晶格常数为a=0.91nm。二十面体准晶相到γ₁相的转变为扩散型相变、伴随着长程准周期序的破坏和原子团的瓦解。γ₁相的形成经历了形核与晶粒长大阶段，其生长主要受Al原子和Cu原子扩散的控制。

关键词：亚稳二十面体准晶；Al-Cu-Cr；相变；TEM原位加热

中图分类号：O753⁺.3；O792；TG115.21⁺5.3    文献标识码：A     doi:10.3969/j.issn.1000-6281.2015.05.007

In-situ TEM investigation on icosahedral quasicrystal-to-crystal transformations in rapidly solidified Al-Cu-Cr alloy

WANG Rui-ping，SUN Wei^*，ZHOU Ling-ling

(Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100024, China)

Abstract：The phase transformation process of the Cr-rich metastable icosahedral quasicrystal phase (I-phase) during heating the rapidly-solidified Al₇₀Cu₁₀Cr₂₀alloy were investigated by means ofin-situ TEM technique. It was observed that, when the heating temperature reached 700℃, the Cr-rich metastable I-phase transformed into the crystalline γ₁-phase with a bcc structure and lattice constant of 0.91 nm. The I-to-γ₁phase transformation is a diffusion-controlled process including nucleation and grain growth of the γ₁-phase, along with degradation of long-range quasiperiodic order and disintegration of the atomic clusters in the I-phase. The growth of the γ₁-phase is mainly dominated by the diffusion of Al and Cu atoms.

Keywords：Al-Cu-Cr；icosahedral quasicrystal；phase transformation；TEM in-situ heating

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