The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening r...The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening response than Zr added alloy,which is attributed to the fact that partitioning of Mn into the β'phases,β'precipitates and long period stacking ordered(LPSO)phases leads to the decrement in(G d+Y)concentrations in the second phases,facilitating the precipitation during aging treatment.Both peak-aged alloys show bimodal microstructure comprising the fine DRXed grains with nano-sized β phases pinned at DRXed grain boundaries as well as coarse worked grains with strong fiber texture.High strength and good thermal stability were obtained in both peak-aged Mn and Zr added alloys.While the peak-aged Mn added alloy shows higher strength and superior creep resistance due to its denser β'precipitates,thin LPSO phases and γ'precipitates and higher area fraction of worked grains with strong fiber texture.The 0.2% tensile proof stress and ultimate tensile strength of peak-aged Mn added alloy reach up to 454 MPa and 508 MPa,respectively,with elongation of 3.2%at room temperature.The minimum creep rate of the peak-aged Mn added alloy at 250℃/150 MPa is 2.4 × 10^-8 s^-1,which is superior than previously reported extruded Mg-Gd based alloys.展开更多
The homogenized Mg-8.2 Gd-3.8 Y-1.0 Zn-0.4 Zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cool...The homogenized Mg-8.2 Gd-3.8 Y-1.0 Zn-0.4 Zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this work.The results show that in comparison with the extruded sample cooling in the atmosphere,the forced-air cooling restricts dynamic recrystallization(DRX)and brings about finer dynamic recrystallized(DRXed)grain size,stronger basal texture and higher dislocation density.Furthermore,the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases andγ’phases with smaller interspacing in the unrecrystallized(un DRXed)regions,then slightly restricts the precipitation ofβphases during aging.After peak-ageing treatment,the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa,an ultimate tensile strength of 493 MPa,and elongation to failure of 18.6%.展开更多
基金This work was supported by National Natural Science Foundation for Young Scientists of China,Grant No.51801042 and 51704088Fundamental Research Funds for the Central Universities,National Natural Science Foundation,Grant No.51775150JSPS KAKENHI Grant-in-Aid for Young Scientists,Grant No.JP 16K18266,and JST,Advanced Low Carbon Technology Research and Development Program(ALCA),Grant No.12102886.
文摘The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening response than Zr added alloy,which is attributed to the fact that partitioning of Mn into the β'phases,β'precipitates and long period stacking ordered(LPSO)phases leads to the decrement in(G d+Y)concentrations in the second phases,facilitating the precipitation during aging treatment.Both peak-aged alloys show bimodal microstructure comprising the fine DRXed grains with nano-sized β phases pinned at DRXed grain boundaries as well as coarse worked grains with strong fiber texture.High strength and good thermal stability were obtained in both peak-aged Mn and Zr added alloys.While the peak-aged Mn added alloy shows higher strength and superior creep resistance due to its denser β'precipitates,thin LPSO phases and γ'precipitates and higher area fraction of worked grains with strong fiber texture.The 0.2% tensile proof stress and ultimate tensile strength of peak-aged Mn added alloy reach up to 454 MPa and 508 MPa,respectively,with elongation of 3.2%at room temperature.The minimum creep rate of the peak-aged Mn added alloy at 250℃/150 MPa is 2.4 × 10^-8 s^-1,which is superior than previously reported extruded Mg-Gd based alloys.
基金financially supported by the National Natural Science Foundation for Young Scientists of China(Nos.51801042 and 51704088)the National Natural Science Foundation(Nos.51971075 and 51775150)+2 种基金the Fundamental Research Funds for the Central Universitiesthe JST Advanced Low Carbon Technology Researchthe Development Program(ALCA)(No.12102886)。
文摘The homogenized Mg-8.2 Gd-3.8 Y-1.0 Zn-0.4 Zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this work.The results show that in comparison with the extruded sample cooling in the atmosphere,the forced-air cooling restricts dynamic recrystallization(DRX)and brings about finer dynamic recrystallized(DRXed)grain size,stronger basal texture and higher dislocation density.Furthermore,the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases andγ’phases with smaller interspacing in the unrecrystallized(un DRXed)regions,then slightly restricts the precipitation ofβphases during aging.After peak-ageing treatment,the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa,an ultimate tensile strength of 493 MPa,and elongation to failure of 18.6%.
