Abstract In this study, the Zn-1.6 Mg alloy was processed by multi-pass equal channel angular pressing (ECAP) at three different temperatures to investigate its microstructural evolutions and mechanical properties. The obtained… Click to show full abstract
Abstract In this study, the Zn-1.6 Mg alloy was processed by multi-pass equal channel angular pressing (ECAP) at three different temperatures to investigate its microstructural evolutions and mechanical properties. The obtained results showed that the microstructure of the as-cast alloy consisted of α-Zn primary phase and a three-component eutectic structure: α-Zn + Mg2Zn11 + MgZn2. The α-Zn and Mg2Zn11 phases exhibited typical rod eutectic morphology, and MgZn2 nanoscale particles were precipitated within Mg2Zn11 phase. Multi-pass ECAP stimulated dynamic recrystallization (DRX) of primary α-Zn grains and crush of eutectic structure gradually. High ECAP temperature accelerated the growth of α-Zn and Mg2Zn11 grains, while MgZn2 nanoscale particles showed no obvious growth owing to their good thermostability. Moreover, low temperature promoted the formation of a bandlike microstructure, while high temperature resulted in a homogeneous microstructure. Tensile tests demonstrated that the 12p ECAP alloy processed at 150 °C possessed the optimal mechanical properties with ultimate tensile strength of 423 MPa, yield strength of 361 MPa and elongation of 5.2%. The simultaneously enhanced strength and ductility could be ascribed to the combined effect of fine DRX grains, refined Mg2Zn11 s phase particles, MgZn2 nanoscale particles, and the precipitation of new MgZn nano-particles within α-Zn grains.
               
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