Enhanced fatigue crack propagation resistance in a superhigh strength Al–Zn–Mg

Enhanced fatigue crack propagation resistance in a superhigh strength Al–Zn–Mg–Cu alloy by modifying RRA treatment

Xia Peng Liu Zhiyi Bai Song Lu Luqing Gao Lifang · 2016

阅读量：251

期刊名称：

Materials Characterization 2016 年 118 卷

发表日期：

2016.08.01

摘要：

A new retrogression and re-aging (RRA) treatment was designed to enhance the fatigue crack propagation (FCP) resistance of a superhigh strength Al??“Zn??“Mg??“Cu alloy in this work. As compared to traditional RRA treatments, a lower retrogression temperature and a longer retrogression and re-aging time were employed. This modified RRA processing obtained a coarse precipitates in matrix, and a slightly increased precipitate free zone (PFZ) width at grain boundary. This led to an almost complete transgranular crack propagation, rather than a partial intergranular crack propagation as traditional RRA tempered samples. This kind of fatigue crack propagation manner gave rise to an ultralow FCP rate, comparable to fatigue resistant 2000 series aluminum alloy, in an Al??“Zn??“Mg??“Cu alloy while keeping superhigh tension strength.