Quasi-in-situ analysis of dependency of deformation mechanism and work-hardening behavior on texture in Mg-2Zn-0.1Ca alloy

Abstract

The influence of crystallographic texture on deformation mechanism and work-hardening behavior of the Mg-2Zn-0.1Ca alloy sheet was investigated via quasi-in-situ slip traces analysis. The results show that the sheet displayed a weakened transverse direction (TD) spread texture. The rolling direction (RD) sample exhibited the highest yield strength (104.3 MPa), while the TD samples exhibit the lowest (68.6 MPa), implying a high dependency of yield strength on texture. A deformation mechanism transition were observed in the RD, 45° and TD samples, i.e. basal slip (ε = 0.5%) → basal slip + non-basal slip (ε = 1.5%) → basal slip + non-basal slip + twinning (ε = 7.5%), and non-basal slip was activated to accommodate the imposed deformation due to the increment in an applied shear stress for basal slip with deformation processing. Additionally, the anisotropy of deformation modes is pronounced. At ε = 0.5%, basal slip primarily operated in the grains with high Schmid Factor (SF ≥ 0.35) in TD sample, while in the RD sample, the SFs for basal slip exhibited a wider distribution and prismatic slip also operated. As strain reached to 7.5%, twinning played more important role in the TD sample than the 45° and RD samples. Moreover, the texture has a substantial influence on work hardening behavior. At ε = 1.5%, work hardening rate was governed by SF distribution for basal slip. The sample with more grains exhibiting low SF for basal slip shows higher WH rate. However, twinning plays an important role in effecting work hardening rate at ε = 7.5%, and consequently the TD sample with the greatest area fraction of twin (ftwin) has the highest work hardening rate.