A new Mg-2.2 wt% Zn alloy containing 1.8 wt% Ca and 0.5 wt% Mn has been developed and subjected to extrusion under different extrusion parameters. The finest (~ 0.48 μm) recrystallized grain structures, containing both nano-sized MgZn₂ precipitates and α-Mn nanoparticles, were obtained in the alloy extruded at 270 °C/0.01 mm s⁻¹. In this alloy, the deformed coarse-grain region possessed a much stronger texture intensity (~ 32.49 mud) relative to the recrystallized fine-grain region (~ 13.99 mud). A positive work hardening rate in the third stage of work hardening curve was also evident in the alloy extruded at 270 °C, which was related to the sharp basal texture and which provided insufficient active slip systems. The high work hardening rate in the fourth stage contributed to the high ductility extruded at 270 °C/1 mm s⁻¹. This alloy exhibited a weak texture, and the examination of fracture surface revealed highly dimpled surfaces. The optimum tensile strength was achieved in the alloy extruded at 270 °C/0.01 mm s⁻¹, and the yield strength, ultimate tensile strength and elongation to failure were ~ 364.1 MPa, ~ 394.5 MPa and ~ 7.2%, respectively. Fine grain strengthening from the recrystallized fine-grain region played the greatest role in the strength increment of this alloy compared with Orowan strengthening and dislocation strengthening in the deformed coarse-grain regions.

中文翻译：

---

Mg-Zn-Ca-Mn镁合金挤压成形的组织，拉伸性能和加工硬化行为

已经开发了一种新的Mg-2.2 wt％的Zn合金，该合金包含1.8 wt％的Ca和0.5 wt％的Mn，并在不同的挤压参数下进行挤压。在270°C / 0.01 mm s ^-1下挤压的合金中获得了同时包含纳米级MgZn ₂沉淀物和α-Mn纳米颗粒的最佳（〜0.48μm）重结晶晶粒结构。。在这种合金中，相对于再结晶的细晶粒区（〜13.99泥浆），变形的粗粒区具有更高的织构强度（〜32.49泥浆）。在270°C挤压的合金中，在第三阶段的加工硬化曲线中也显示出正的加工硬化率，这与基部的锐利组织有关，并且提供了不足的活动滑移系统。第四阶段的高加工硬化率有助于在270°C / 1 mm s ^-1下挤出的高延展性。该合金表现出较弱的织构，并且断裂表面的检查显示出高度凹陷的表面。在270°C / 0.01 mm s ^-1挤压的合金中获得了最佳的拉伸强度的屈服强度，极限抗拉强度和破坏伸长率分别为〜364.1 MPa，〜394.5 MPa和〜7.2％。与在变形的粗晶粒区域中的Orowan强化和位错强化相比，从再结晶的细晶粒区域进行的细晶粒强化在该合金的强度增加中起最大作用。