Stamping formability of pre-compressed magnesium sheets
{ 1012 } tensile twinning was introduced in AZ31 magnesium alloy sheets by pre-compressing along different directions with the same deformation.The first group of magnesium sheets were pre-compressed along rolling direction(RD)by 1％,3％and 5％,first,and then pre-compressed along TD by 2％(named RT magnesium sheets:R1T2,R3T2 and R5T2).The second group of magnesium sheets were pre-compressed along TD by 2％first,and then pre-compressed along RD by 1％,3％and 5％(named TR magnesium sheets:T2R1,T2R3 and T2R5).Then all magnesium sheets were annealed at 400 ℃ for 3 h to study the static recrystallization and stamping formability behavior of each pre-twinning magnesium sheets.The results show that the larger the pre-compression deformation of magnesium sheets,the more twins.And the volume fraction of twinning in TR magnesium sheets is obviously large than that in RT magnesium sheets un-der the same precompression condition.After annealing at high temperature,the grain size of the magnesium sheets with the larger pre-com-pression deformation is finer.And the grain size of TR magnesium sheets is finer and more uniform compared with RT magnesium sheets un-der the same pre-compression condition.The yield strength,ultimate tensile strength and elongation of magnesium sheets increase with the increase of pre-compression deformation.The yield strength,ultimate tensile strength and elongation of TR magnesium sheets are higher than those of RT magnesium sheets under the same precompression.The Erichsen values of magnesium sheets increase significantly with the in-crease of pre-compression deformation.The Erichsen values of TR magnesium sheets are higher than that of RT magnesium sheets under the same pre-compression,which is closely attributed to the excellent ductility,small plastic strain ratio and large work hardening index.
NETL
NSTL
万方数据
