Mechanistic investigation of highly bendable magnesium alloy sheet fabricated by short-process manufacturing

•Despite strong basal texture, short-processed AZ31 sheet has outstanding bend formability.•Twinning-detwinning alleviates the local high strain, allowing repeated bending.•Outstanding bend formability originated from active dislocation loop on prismatic and low residual strain, revealed by in-situ observations.•Grain refinement and the resultant effective grain boundary hardening decreases relative activation stress of prismatic to basal slip.•Al-Mn nano-particles serve as sources for prismatic loop multiplication.