Fig. 1 Sampling position and dimensions of the samples used for the microstructure observations, tensile tests, and corrosion experiments (units: mm). AS represents the advancing side, and RS represents the retreating side. PD, TD, and ND represent the processing, transversal, and normal directions, respectively

Fig. 2 Cross-sectional macrostructure of the FSP sample

Fig. 3 Grain morphologies a, b, grain boundaries distributions c, d of BM and FSP samples

Fig. 4 SEM images showing the second phase particles of the a BM, b FSP samples

Fig. 5 Bright field TEM images and EDS maps of the a-c BM, d-f FSP samples

Fig. 6 XRD patterns of the BM and FSP samples

Fig. 7 a, b Pole figures, c, d SF distributions of basal slips along the TD for the BM (left) and FSP (right) samples

Fig. 8 Engineering stress-strain curves of the BM and FSP samples

Fig. 9 Corrosion rates of the BM and FSP samples convert from the weight loss

Fig. 10 SEM morphologies after different immersion time: a, d 3 h, b, e 24 h, and c, f 48 h for the BM (first row) and FSP (second row) samples; g, h enlarged diagrams of points a and b in a, d, respectively. i EDS spectra of point c in h

Fig. 11 Potentiodynamic polarization curves of the BM and FSP samples in 3.5 wt% NaCl solution

Fig. 12 Fracture surfaces of the SSRT test samples: a, d in air; b, e in solution for the BM (first row) and FSP (second row) samples; c, f enlarged diagrams of the selected areas in b, e

Fig. 13 UTS and El comparison of Mg-Al-Ca alloys prepared through different SPD technologies

Fig. 14 Schematic illustration of the proposed SCC mechanism of the BM and FSP samples