Mechanical Properties and Microstructure Evolution of Mg-6 wt % Zn Alloy during Equal-Channel Angular Pressing

Abstract

Equal-channel angular pressing (ECAP) was performed on a Mg (6 wt %) Zn alloy at temperatures from 160 to 240 °C and the microstructures and mechanical properties were studied using optical microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and an electronic universal testing machine. The results showed that ECAP was effective for grain refinement and a bi-modal grain structure formed at low temperatures, which was stable during ECAP from 160 to 200 °C. MgZn2 phase and Mg4Zn7 phase were generated during the ECAP process. The mechanical properties remarkably increased after two repetitions of ECAP. However, the strengths could not be further improved by increasing the plastic deformation, but decreased when ECAP was performed between 200 and 240 °C. The mechanical properties of the ECAP Mg-6Zn alloy was determined by a combination of grain refinement strengthening, precipitation hardening, and texture softening.

An Investigation on Microstructure, Texture and Mechanical Properties of AZ80 Mg Alloy Processed by Annular Channel Angular Extrusion

“…Actually, its formation is closely associated with the activation of the basal slip system that causes rotation of the grain’s basal plane toward to the geometric slip plane (shear plane) of mold’s corner. Similar texture components have also been observed previously in Mg-based alloys processed by ECAP [9,31,32]. In the current deformation process, the entire basal texture evolution can be clearly described using Figure 9.…”

“…In this respect, the most severe plastic deformation processes (SPD) show unparalleled advantages in improving the mechanical properties of Mg alloys due to their excellent microstructure refining ability and texture modification ability. A fine grain structure, accompanied with tilted shear texture, has already been widely reported in Mg alloys deformed through equal channel angular process (ECAP) [9,10]. Wang et al [11] systematically investigated the capacity of cyclic extrusion and compression (CEC) in improving the microstructure, mechanical properties, and developing nonbasal texture, which included AZ31, AZ61, and AZ91 Mg alloys.…”

Bio-fabrication and experimental validation of an Mg – 25Ca – 5Zn alloy proposed for a porous metallic scaffold.

“…The lack of identi cation of Zn phases can be attributed to multiple causes, including a possible preferential reorientation during the preparation of the specimens, unfortunately Yan Jingli does not report a scanning speed for the detection of the MgZn2 phases by XRD, the value used in this work corresponds to scan step time [s], 59.69, which suggests that a lower speed should be used. An atomic rearrangement by a mechanism such as hardening deformation will increase the intensity of Zn (128).…”

Enhancing Mechanical Properties of Mg–6Zn Alloy by Deformation-Induced Nanoprecipitation

“…The fully homogenization is the prerequisite for high-density nanoprecipitation. The high-temperature SPD could clearly accelerate homogenization and promote the single-phase structure in Mg-6Zn alloy when the temperature is up to the melting point of the intermetallic phase (about 325 °C) [36,37]. After that, the increasing supersaturation of the solute resulted in the spontaneous precipitation of massive directional aligned rod-like nano-sized Mg 4 Zn 7 phase from the single-phase supersaturate solid solution.…”

“…The average grains size depended strongly on the extrusion temperature during the multi-pass ECAP processing [37]. The six passes ECAP at 160 °C produced the ultrafine grains by dynamic recrystallization, as well as strong texture and high-density dislocations.…”