Fig. 1 a Schematic diagram of pin centerline deviation, b dimensions of the tensile specimen, c EBSD micrograph of microstructure of AA7075 base material, d original coarse secondary phase particles, e dislocation distribution

Fig. 2 Arranged position of blind hole for measuring temperature during FSW

Fig. 3 Cross sections of the joints produced by different pins with centerline deviations of a 0, b 0.1, c 0.2, d 0.3

Fig. 4 Moving paths of different pins during FSW process

Fig. 5 a Thermal cycles curves during FSW, b peak temperature of the NZs

Fig. 6 Models of action force in the NZs during FSW: a without, b with pin centerline deviation

Fig. 7 Grain sizes in the NZs produced by different pins with a 0 mm, b 0.1 mm, c 0.2 mm, d 0.3 mm centerline deviation

Fig. 8 Distribution of secondary phase particles in the NZs produced by different pins with a, e 0 mm, b, f 0.1 mm, c, g 0.2 mm, d, h 0.3 mm centerline deviation

Fig. 9 Distribution of dynamic recrystallization in the NZs obtained by different pins with a 0 mm, b 0.1 mm, c 0.2 mm, d 0.3 mm centerline deviation and e statistical results of different grains

Fig. 10 Misorientation angle distribution in the NZs produced by different pins with a 0 mm, b 0.1 mm, c 0.2 mm, d 0.3 mm centerline deviation

Fig. 11 a Microhardness, b tensile properties of the joints made by pins with different centerline deviations

Fig. 12 DIC results for strain distribution of different joints produced by different pins with a 0 mm, b 0.1 mm, c 0.2 mm, d 0.3 mm centerline deviation

Fig. 13 SEM micrographs of tensile fracture surfaces of the joints produced by different pins with a-c 0 mm, d-f 0.2 mm centerline deviation