Search

The rolling direction (RD) and transverse direction (TD) samples with distinct difference in initial texture were cut from differential speed rolled ZK60 magnesium alloy sheet and were subsequently subjected to the bending process. The bending behavior, microstructure and texture evolution of the bending samples were investigated to argue the effect of initial texture during the bending process. Results revealed that conspicuous asymmetry in the bending behavior was ascribed to the initial texture, and weaker basal texture was favorable to improve the bending properties. Meanwhile, initial texture remarkably influenced the microstructure characteristics, especially the number and morphology of (10–12) tension twin. Texture results revealed that initial texture in conjunction with the deformation mode led to the difference in texture evolution by influencing the deformation mechanism: (10–12) tension twin for the inner region of the RD sample; basal slip and prismatic slip for the outer region of the RD sample; basal slip and (10–12) tension twin for the TD sample. In addition, the bending behavior was reflected well by finite element method, and was investigated by strain-hardening curves based on experimental tests. Results suggested that the priority of deformation mechanism was dependent on the initial texture.

Ductility enhancement up to about 28–39% in fracture elongation with simultaneous strengthening was achieved in fine-grained magnesium and magnesium alloy sheets by multi-pass rolling with lowered temperature suitable for industrial fabrication. Specifically, high strengths at yielding following slip-dominated Hall–Petch relations were achieved owning to the naturally twinning's replacement by pyramidal under intense basal texture. These Hall–Petch relations had a high slope of 190 MPa μm 1/2 and frictional stresses ranging from 40 MPa to 144 MPa. The variation in frictional stress matched well with solid solution hardening and/or precipitation hardening. Enhanced uniform elongation was strongly correlated with improved strain-hardening rate via introducing solid solution and/or fine precipitates in Mg alloys compared with pure Mg, and conversely post-necking elongation (local elongation) as well as cold-workability under compressive stress was strikingly weakened by the restriction of dynamic recovery.