Enhancement of tensile ductility and stretch formability of AZ31 magnesium alloy sheet processed by cross-wavy bending

• The AZ31 Mg alloy sheet is deformed to 4 passes at 673 K by cross-wavy bending.
• A fine-grained microstructure and a weak and random texture are achieved.
• Different softening mechanisms significantly affect the microstructure evolution.
• The tensile ductility and stretch formability enhance dramatically.

The microstructure and texture evolution in the sheets of AZ31 magnesium alloy was studied by means of cross-wavy bending for 4 passes at 673 K. The bended samples were examined by optical microscopy and electron backscatter diffraction analysis. Finite element analysis suggested an inhomogeneous deformation at each pass. Following cross-wavy bending, a fine-grained microstructure with an average grain size of ∼8 μm and a weak and random basal texture were achieved. Accumulative effective strain was almost equal in the whole sheet at the end. Different work softening mechanisms significantly affected the evolution of the microstructure. Dynamic recovery played an important role during the first three bending passes whereas, in contrast, dynamic recrystallization dominated the evident grain refinement during the last pass. The tensile ductility and stretch formability of the 4-pass sheet at room temperature were distinctly enhanced compared to the initial sheet (1.55 and 2 times larger, respectively). These prominent increases were mainly attributed to texture randomizing rather than texture weakening alone.

Figure optionsDownload as PowerPoint slide