The role of recrystallization on fatigue crack propagation of a high alloying Al-Zn-Mg-Cu alloy

•Focus on the effect of recrystallization on FCP rate of an Al-Zn-Mg-Cu alloy.•FCP rate firstly decrease and then increase as recrystallization fraction increase.•A quadratic correlation between FCP rate and recrystallization fraction is proposed. Recrystallization could affect the fatigue performance of aluminum alloys by changing grain structure while the influence mechanism was not clear yet. To issue this problem, a high-alloying Al-Zn-Mg-Cu alloy with various recrystallization fractions obtained by solution treatment was investigated. The results of fatigue crack propagation (FCP) rate tests showed that with the deepening of recrystallization, FCP rate of the alloy decreased firstly and then increased, reaching a minimum FCP rate at a recrystallization fraction of 16.98%. These results are discussed in terms of recrystallization fraction and the size of recrystallization grain with the help of the mathematical model presented by Zheng and Manfred.