Improvement in bending formability of rolled magnesium alloy through precompression and subsequent annealing

Unusual Spreading of Strain Neutral Layer in AZ31 Magnesium Alloy Sheet during Bending

“…In position I, the boundaries of SNL in Figure 3a are nearly parallel with each other, which is in the region between the CSR and the TSR. This phenomenon is consistent with the results reported by Lee et al [13], Singh et al [37] and Jin et al [23]. For example, Lee et al [13] observed the side surface of the bent sample using an optical microscope and also found that the boundaries of SNL are nearly parallel with each other.…”

“…This phenomenon is consistent with the results reported by Lee et al [13], Singh et al [37] and Jin et al [23]. For example, Lee et al [13] observed the side surface of the bent sample using an optical microscope and also found that the boundaries of SNL are nearly parallel with each other. The SNL boundary extends to the compressed region in position II, as shown in Figure 3e.…”

“…Therefore, how to improve the formability of magnesium alloys has become a meaningful and urgent topic. During sheet forming, such as deep drawing and hemming, the material at the corner of the part undergoes bending deformation [13,14]. Therefore, bendability is an essential indicator that represents the formability of Mg alloy sheets.…”

Influence of Wavy Bending on Microstructure and Mechanical Properties of a Rolled AZ31 Sheet

“…Figure 7 shows that compressive strain and tensile strain alternate on the sheet surface during wavy bending. During wavy bending, the compressed regions can favorably activate the {10-12} twins and the c-axes of twins gather at compressive direction [25]. Thus, it infers that twins with c-axis//RD texture, c-axis//45° texture and c-axis//TD texture could be formed during 1st, 2nd and 3rd wavy bending, respectively.…”

“…Thus, {10-12} twins can remarkably change the orientation of the lattice, but exhibits little influence on the overall texture of the WB sample. For the bending deformation, the outer region is under tension while the inner region is under compression and the stress axis parallels bending direction [25]. It is well known that {10-12} twinning can be favorably activated when the compression along the bending direction of the sheet, and are suppressed when then tension along the bending direction [18].…”