Microstructure and high tensile ductility of ZK60 magnesium alloy processed by cyclic extrusion and compression

Microstructure and enhanced mechanical properties of an Mg–10Gd–2Y–0.5Zr alloy processed by cyclic extrusion and compression

“…The materials were received in the form of an extruded bar with a diameter of 29.5 mm and then cut into pieces of length 42 mm before CEC processing. The CEC die used in this investigation and its operation procedure was described elsewhere [15][16][17]. The CEC processing was carried out by pushing a specimen from one cylindrical chamber with a diameter D, into the second chamber with the same dimensions, through a die having a smaller diameter d. In the present study, D and d are 30 mm and 20 mm, respectively.…”

<i>In-Situ</i> Study on Deformation Behavior of ZK60 Alloy Processed by Cyclic Extrusion and Compression

“…7(a)), the fracture surface contained typical cleavage facets and cleavage steps, which formation has been related to the cracking of twinning. 7) In contrast, an obviously uniform deformation character is exhibited for the CEC processed ZK60 alloy after tensile fracture (Fig. 7(b)).…”

“…2,7,8) In order to examine the effects of CEC deformation on the plastic deformation and fracture mechanisms of the ZK60 alloy, the changes in the surface morphology during tensile plastic deformation is observed. Figure 4 shows the microstructure evolution of the surface morphologies of the as-extruded ZK60 alloy during in-situ tensile testing.…”

“…5(b)), grains are seriously elongated along the tensile direction and grain boundaries are undistinguishable. The multiple and intersection slip lines indicate that the major deformation mechanism is changed from single-slip to multi-slip, due to the grain refinement 14) and texture modification 7) induced by the CEC deformation. In addition, the coarse f10 12gh10 11i twins is apparently suppressed by grain refinement 16,17) due to the increasing stress required for twin nucleation (i.e., twin nucleation stress).…”

“…As a kind of continuous SPD technique, cyclic extrusion and compression (CEC) is very suitable to refine grains of hard-deformation metals because the materials are imposed by three-dimensional compression stress during the CEC processing. 7,8) Previous studies on the CEC processed Mg alloys revealed that the microstructure was effectively refined and the room temperature ductility was significantly enhanced by CEC processing.…”