Abstract Experiments were carried out to investigate the compressive mechanical properties of an Al-Zn-Mg-Cu alloy after spray forming and extrusion followed by T74 heat treatment (393 K for 8 h + 433 K for 24 h). The results show that the yield and ultimate strengths are enhanced after the T74 heat treatment under strain rates ranging from 1.0 × 10−3 s−1 to 5.0 × 103 s−1 due to the large number of precipitates. Elongated grains are fragmented forming grains with low angle grain boundaries (LAGB's) under 3.0 × 103 s−1 and 5.0 × 103 s−1 before and after the heat treatment influenced by the dislocation accumulation. Adiabatic shear bands (ASBs) are formed after high strain rate compression assisted by local shear and temperature rise in a narrow region forming fine recrystallized grains accompanied by the initiation of micro-cracks. There is a slight variation in the volume fraction of precipitates before and after compression. Precipitates are also fragmented under high strain rate compression to form spherical and irregular morphologies from the original platelet morphology before compression.

中文翻译：

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应变速率对过时效Al-Zn-Mg-Cu合金显微组织和力学性能的影响

摘要 通过实验研究了Al-Zn-Mg-Cu 合金在喷射成形和挤压后T74 热处理（393 K 8 h + 433 K 24 h）的压缩力学性能。结果表明，由于大量析出物，在应变速率范围为 1.0 × 10-3 s-1 至 5.0 × 103 s-1 的情况下，T74 热处理后屈服和极限强度得到提高。拉长晶粒是在热处理前后在 3.0 × 103 s-1 和 5.0 × 103 s-1 下具有低角度晶界 (LAGB's) 的破碎形成晶粒，受位错积累的影响。绝热剪切带（ASBs）是在局部剪切和温度升高的辅助下在狭窄区域进行高应变率压缩后形成的，形成细小的再结晶晶粒，伴随着微裂纹的萌生。压缩前后析出物的体积分数略有变化。沉淀物也在高应变率压缩下破碎，从压缩前的原始片状形态形成球形和不规则形态。