Microstructure and Mechanical Properties of Large ZK60 Magnesium Alloy Extruded Profiles
ZK60 magnesium alloy I-shaped sections profiles with circumcircle diameter 179mm were formed under the conditions of the extrusion temperature 400℃, the extrusion speed 5mm/s and the extrusion ratio 25. The microstructures and mechanical properties of the profiles were studied by using XRD, optical microscopy, scanning electron microscopy and tensile test method at room temperature. The results indicate that there are α-Mg, MgZn2main phases and a small amount of Mg2Zn11, Zn2Zr3phases. Alloy grains are broken by squeezing action, and the alloy produces incomplete dynamic recrystallization during the extrusion process, the graines are refined and distributed along the extrusion direction in a streamline. The fine second phase particles disperse in α-Mg matrix. Tensile test at room temperature shows that the extruded ZK60 magnesium alloy has obvious anisotropy. The tensile strength of the sample in extrusion direction is the highest(325MPa) and the elongation of the sample with the extrusion direction 45° is maximum(23%).