Ductility improvement methods for commercial AZ31B magnesium alloy in cold forging

In order to realize cold forging of magnesium alloys in practical application, some methods for ductility improvement of a commercial wrought AZ31B magnesium alloy (Mg-3%Al-1%Zn, mass fraction) at room temperature were suggested. The effects of heat treatment before forging and hydrostatic pressure during forging on the ductility were investigated in cold upsetting and cup forging. High-temperature annealing was effective to reduce the degree of the texture anisotropy of the specimen, and it was found that the forging limit of the annealed specimen was improved in cold forging. On the other hand, cold cup forging of the annealed specimen was carried out with applying counter pressure. By applying counter pressures of 100-200 MPa during forging, the critical punch stroke for forging limit of the specimen without crack was improved by 25% in punch stroke.