Enhancing stretch formability of rolled Mg sheets by pre-inducing contraction twins and recrystallization annealing

Effect of the final rolling speeds on the stretch formability of AZ31 alloy sheet rolled at a high temperature

“…It is well known that the nvalue and r-value is strongly influenced by the texture of the sheet. For grains with the tilt basal texture, and the thickness strain can be accommodated by basal slip, prismatic slip and extension twinning [30]. So the r-value can be effectively decreased by the weakened basal texture.…”

“…So the r-value can be effectively decreased by the weakened basal texture. Meanwhile, with the weakened basal texture, the softening behaviour of dynamic recovery resulted from the crossslip of 〈a〉 dislocations from basal to prismatic planes can be restricted [30] and the {1012} twinning can be activated [11], which leads to the increase in the n-value.…”

Review of Formability in Relation to Texture

“…Even though the tensile strength is insensitive to the texture, a decrease of proof stress 0.2% resulted in tilting of the basal plane about 7 o . Due to the inclination of basal plane from the rolling plane, the Schmid factor increases, causing the basal slip [20]. Smaller r-value and a larger n-value (shown in table 1) especially in the rolling direction, which is due to the inclination of the basal pole in the rolling direction indicates less normal anisotropy intern more formability although there is slight in-plane anisotropy present in the sheet.…”

“…For both the sheets there is no specific orientation of (1 0 1) poles is observed. The c-axis orientation is extremely interrelated to the uniaxial severe shear deformation throughout thickness direction [19], [20]. Even though the tensile strength is insensitive to the texture, a decrease of proof stress 0.2% resulted in tilting of the basal plane about 7 o .…”

“…Smaller r-value and a larger n-value (shown in table 1) especially in the rolling direction, which is due to the inclination of the basal pole in the rolling direction indicates less normal anisotropy intern more formability although there is slight in-plane anisotropy present in the sheet. [19][20] 5. Formability-Texture Fig 4: The relationship between Erichsen value and texture [21] Fig 5: Relation between Erichsen value and texture in Mg-3% Al-1% Zn alloy sheet [21] The relation between erichsen values and texture was studied by Iwanaga et al [21].…”