Study of the microstructure, texture and tensile properties of as-extruded AZ91 magnesium alloy

The microstructure, texture and tensile properties of AZ91 magnesium alloy that was extruded at 300 and 360 °C with extrusion ratios of 5.5 and 22 are investigated. The occurrence of dynamic recrystallization, precipitation of second phase (Mg17Al12) particles and the formation of basal texture during extrusion are observed by electron back scattered diffraction patterns analyses. Along with the increase of either the extrusion temperature or extrusion ratio, the tensile strength decreases and the ductility increases. The precipitation of the second phase is beneficial to the grain refinement and in turn to the promotion of the tensile strength. The fracture analysis shows that the deformation twinning plays an important role in increasing the elongation.