Fig. 1. (a) Illustration of the detailed experimental procedures and the 3D EBSD IPF maps for (b) hot-rolled and (c) UCQ samples.

Fig. 2. The residual stress magnitudes for quenched samples under different conditions.

Fig. 3. (a) Heat transfer coefficients and (b) quenching cooling curves obtained from experiment and simulation under different quenching conditions.

Fig. 4. The residual stress distributions for (a) UCQ and (b) CQ1 specimens estimated by FEA.

Fig. 5. Residual stresses on different locations of (a) UCQ and (b) CQ1 specimens obtained by FEA corresponding to Fig. 4.

Fig. 6. The simulation result for residual stress in the sample after wire cutting from the UCQ specimen. The size of the cut sample is 8 mm × 8 mm × 40 mm.

Fig. 7. Vickers hardness distribution at different locations of the directly aged samples (AA-D): (a) location 1; (b) location 2; (c) location 3; (d) location 4. The AA treatments (120 °C / 24 h) are directly implemented for specimens with a length and width of 160 mm and 80 mm after various quenching processes, as shown in Fig. 1.

Fig. 8. Engineering stress-strain curves of different samples.

Fig. 9. Vickers hardness distribution on different locations of various samples: (a) UCQ & UCQ-AA-D & UCQ-AA-C; (b) CQ1 & CQ1-AA-D & CQ1-AA-C.

Fig. 10. TEM BF images and corresponding SAED patterns on the surface and centre of UCD-AA-D1 and UCD-AA-C1 samples (along the <110>Al axis): (a-c) UCQ-AA-D1-S; (d-f) UCQ-AA-C1-S; (g-i) UCQ-AA-D1-C; (j-l) UCQ-AA-C1-C.

Fig. 11. The precipitate radius distribution under different conditions corresponding to Fig. 9: (a) UCQ-AA-D1-S; (b) UCQ-AA-C1-S; (c) UCQ-AA-D1-C; (d) UCQ-AA-C1-C.

Fig. 12. Quenching cooling curves on the top surface centre (TSC) and body centre (BC) of various samples and the gap in temperature (ΔT) between these two points.

Fig. 13. Summarization of the TTP curve for 7085 Al alloy [55] and the experimental quenching cooling curves obtained in this work.

Fig. 14. TEM BF images of the UCQ-AA-D1-S sample.

Fig. 15. (a) The in situ electrical resistivity (Δρ) and (b) corresponding derivative evolution for the CQ1-0 and CQ1-T120 samples; (c-f) STEM-HAADF images and corresponding precipitate radius distributions for the CQ1-0 and CQ1-T120 samples at 10800 s and 86400 s (along the <110> Al axis).

Fig. 16. Schematic diagram of the influence mechanisms for quenching residual stress on the ageing process.