The effects of Al addition on the deformation behavior and high-temperature mechanical properties of an extruded Mg–Y–Zn–Co (YNC) alloy were systematically investigated. The results indicated that Al addition promoted the formation of heat-resistant long period stacking ordered (LPSO) phases, nanoscale (Al, Zn)2Y phases at the grain boundaries. Specifically, the synergistic effect of these Al-induced precipitates and the solute segregation (Zn and Y) at grain boundaries effectively inhibits grain coarsening. The deformation behavior of both the extruded YNC and Mg–Y–Zn–Co–Al (YNCA) alloys was predominantly governed by dislocation slip at low temperatures (RT < T < 200 °C) under different strain rates and 300 °C under high strain rates <InlineEquation ID="IEq1"> <EquationSource Format="TEX">${1}\, \times \,{1}0^{{ - {1}}} {\text{s}}^{{ - }{1}} \, < \,\mathop \varepsilon \limits^{ \cdot } \,\, < \,{1}\, \times \,{1}0^{{ - {3}}} {\text{s}}^{{ - }{1}}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>1</mn> <mspace width="0.166667em" /> <mo>×</mo> <mspace width="0.166667em" /> <mn>1</mn> <msup> <mn>0</mn> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msup> <mrow> <mtext>s</mtext> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mspace width="0.166667em" /> <mo><</mo> <mspace width="0.166667em" /> <mover> <mi>ε</mi> <mo>·</mo> </mover> <mspace width="0.166667em" /> <mspace width="0.166667em" /> <mo><</mo> <mspace width="0.166667em" /> <mn>1</mn> <mspace width="0.166667em" /> <mo>×</mo> <mspace width="0.166667em" /> <mn>1</mn> <msup> <mn>0</mn> <mrow> <mo>-</mo> <mn>3</mn> </mrow> </msup> <msup> <mrow> <mtext>s</mtext> </mrow> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mrow> </math></EquationSource> </InlineEquation>, whereas it was jointly controlled by dislocation climb and creep, grain boundary diffusion, and grain boundary sliding at 300 °C under a strain rate 1 × 10−4 s−1. Furthermore, the addition of Al reduces the SFE and accelerates atomic diffusion, thereby facilitating the activity of thermal deformation mechanisms. Tensile testing results indicated that the extruded YNCA alloy exhibited high tensile strengths at high temperature, whose tensile yield strength, ultimate tensile strength and elongation to failure reached 174.8 MPa, 196.4 MPa and 107.7% at 300 ℃ under a strain rate of 1 × 10−3 s−1. The excellent high-temperature mechanical properties of the alloy were primarily attributed to the synergistic effect of the fine-grained structure with high thermal stability, the strengthening contribution of LPSO phase and high-density (Al, Zn)2Y phase.

Optimizing the deformation behavior and enhancing high-temperature strength of extruded Mg–Y–Zn–Co alloy via Al addition

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发表日期：

2026年4月18日

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Zhichao Wei,
Jing Jiang,
Wei Yu,
Fang wang,
Guangli Bi,
Yuandong Li,
Tijun Chen

摘要

The effects of Al addition on the deformation behavior and high-temperature mechanical properties of an extruded Mg–Y–Zn–Co (YNC) alloy were systematically investigated. The results indicated that Al addition promoted the formation of heat-resistant long period stacking ordered (LPSO) phases, nanoscale (Al, Zn)₂Y phases at the grain boundaries. Specifically, the synergistic effect of these Al-induced precipitates and the solute segregation (Zn and Y) at grain boundaries effectively inhibits grain coarsening. The deformation behavior of both the extruded YNC and Mg–Y–Zn–Co–Al (YNCA) alloys was predominantly governed by dislocation slip at low temperatures (RT < T < 200 °C) under different strain rates and 300 °C under high strain rates ${1}\, \times \,{1}0^{{ - {1}}} {\text{s}}^{{ - }{1}} \, < \,\mathop \varepsilon \limits^{ \cdot } \,\, < \,{1}\, \times \,{1}0^{{ - {3}}} {\text{s}}^{{ - }{1}}$ $1 \times 1 0^{- 1} s^{- 1} < \overset{\cdot}{ε} < 1 \times 1 0^{- 3} s^{- 1}$ , whereas it was jointly controlled by dislocation climb and creep, grain boundary diffusion, and grain boundary sliding at 300 °C under a strain rate 1 × 10⁻⁴ s⁻¹. Furthermore, the addition of Al reduces the SFE and accelerates atomic diffusion, thereby facilitating the activity of thermal deformation mechanisms. Tensile testing results indicated that the extruded YNCA alloy exhibited high tensile strengths at high temperature, whose tensile yield strength, ultimate tensile strength and elongation to failure reached 174.8 MPa, 196.4 MPa and 107.7% at 300 ℃ under a strain rate of 1 × 10⁻³ s⁻¹. The excellent high-temperature mechanical properties of the alloy were primarily attributed to the synergistic effect of the fine-grained structure with high thermal stability, the strengthening contribution of LPSO phase and high-density (Al, Zn)₂Y phase.