中文摘要：

利用透射电子显微镜原位加热技术研究了快速凝固Al70 Cu10 Cr20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＝0.91 nm。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原子的扩散控制。

英文摘要：

The phase transformation process of the Cr-rich metastable icosahedral quasicrystal phase （ I-phase ） during heating the rapidly-solidified Al70 Cu10 Cr20 alloy were investigated by means of in-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-γ1 phase transformation is a diffusion-controlled process including nucleation and grain growth of theγ1-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.