Microstructure behavior of Al–Mg–Sc alloy processed by ECAP at elevated temperature
Microstructure behavior of Al–Mg–Sc alloy processed by ECAP at elevated temperature
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DOI：
10.1016/j.actamat.2007.10.029
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发表时间：
2008-02
期刊：
影响因子：
9.4
通讯作者：
O. Sitdikov;T. Sakai;E. Avtokratova;R. Kaibyshev;K. Tsuzaki;Yoshimi Watanabe
中科院分区：
文献类型：
--
作者：
O. Sitdikov;T. Sakai;E. Avtokratova;R. Kaibyshev;K. Tsuzaki;Yoshimi Watanabe
研究了粗晶Al-6% Mg-0.4% Mn-0.3% Sc合金在300°C （~ 0.6Tm）等通道角挤压（ECAP）过程中的组织演变。每次通过后，样品被压至12，并在水中淬火。在中高应变下，ECAP可形成晶粒尺寸约为1 μm和8μm，体积分数分别为0.3和0.6的双峰型晶粒结构。新晶粒区域的形成是由于变形过程中发生的连续动态再结晶和变形后的材料在模具中保持在300°C和/或在两次压制之间再加热时发生的静态再结晶同时发生的结果。从再结晶驱动力增强的角度讨论了微观组织的发展，这是由于塑性流动的局部化和恢复的抑制导致高密度位错亚结构的演变而导致的。
Microstructural evolution taking place during equal channel angular pressing (ECAP) was studied in a coarse-grained Al–6% Mg–0.4% Mn–0.3% Sc alloy at 300°C (∼0.6Tm). Samples were pressed to strain 12 and quenched in water after each pass. ECAP at moderate-to-high strains leads to formation of a bimodal grain structure, with grain sizes of about 1 and 8μm and volume fractions of 0.3 and 0.6, respectively. The development of new-grained regions has been shown to result from the concurrent operation of the continuous dynamic recrystallization that occurs during deformation and the static recrystallization that occurs by the exposure of the as-deformed material in the die kept at 300°C and/or reheating between pressings. The microstructural development is discussed in terms of the enhanced driving force for recrystallization, resulting from the evolution of high-density dislocation substructures due to localization of plastic flow and inhibition of recovery in the present alloy.