Effect of intermetallic phases and recrystallization on the corrosion and fracture behavior of an Al-Zn-Mg-Cu-Zr-Yb-Cr alloy

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• 作者：H.C. Fang ; ^{fanghc@csu.edu.cn} ; F.H. Luo ; K.H. Chen
• 关键词：Aluminum alloys ; Intermetallics ; Fracture ; Grain boundaries ; Recrystallization
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：27 January 2017
• 年：2017
• 卷：684
• 期：Complete
• 页码：480-490
• 全文大小：4664 K
• 卷排序：684

文摘

The effects of alloying elements on the characteristics of intermetallic phases and recrystallization in Zr, Yb, Cr-containing Al-Zn-Mg-Cu alloys have been investigated. The results show that the inhibiting recrystallization and subgrain growth behavior mainly could be attributed to the fine, dense, secondary, coherent Cr-containing Al3(Yb, Zr) dispersoids with core-shell structures. The volume fraction of primary and secondary Al18Mg3Cr2 phases decreased and then increased with increasing Cr content from 0.09wt% to 0.22 wt% in the Al-Zn-Mg-Cu-Zr-Yb-Cr alloys. Cr content has little effect on the recrystallization resistance and strengthening effect. Recrystallization of the Al-Zn-Mg-Cu-Zr-Yb-Cr alloys can be attributed to the particle stimulated nucleation (PSN) owing to the presence of primary micro-scale Al2CuMg and Al18Mg3Cr2 particles, resulting in a decline in the fracture toughness, tensile properties and corrosion resistance. In the Al-Zn-Mg-Cu-Zr-Yb-Cr alloys, fracture and local corrosion preferentially initiate from these primary micro-scale particles, and then propagate along the high-angle recrystallized grain boundaries or original grain boundaries with continuous, coarser grain boundary precipitates and broadening precipitate-free zone at its periphery. Compared with Al18Mg3Cr2 discrete particles, the Al2CuMg constituent particles are more susceptible to be corroded.