Effect of Equal Channel Angular Pressing on Microstructure and Mechanical Properties of ZK60 Alloy

Approaches of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction, electron backscattered diffraction (EBSD), transmission electron microscopy (TEM) and mechanical property testing have been used to study the microstructure and mechanical properties of Mg-6.1Zn-0.7Zr alloys before and after equal channel angular pressing (ECAP) investigated in detail using. The study demonstrates that the microstructure comprises of fine-grained equiaxed dynamic recrystallization. The size of various grains is in the range 2.3-5.2 μm along the boundaries of unrecrystallized grains after 6 passes of ECAP. Meanwhile, the Mg-Zn and Mg-Zn-Zr compounds gradually crush into fine dispersed particles and the dislocation density increases. With increase of pass the average (0001) basal slip Schmid factor gradually increases to 0.41. The strength and ductility have improved with increasing of ECAP pass. Notably, after 6 passes, due to decrease of grain size and the strengthening effects of fragmentized secondary phase particles, the ultimate tensile strength increases to 260 MPa, and the elongation at break exceeds 28.6%.