The strength of traditional Al-Mg alloys is relatively low because it mainly relies on solid solution strengthening.Adding a third component to form precipitation can improve their strength,but it usually leads to hig...The strength of traditional Al-Mg alloys is relatively low because it mainly relies on solid solution strengthening.Adding a third component to form precipitation can improve their strength,but it usually leads to high-stress corrosion cracking(SCC)sensitivity due to the formation of high-density precipitates at grain boundaries(GBs).So far,it is still challenging to improve the strength of Al-Mg alloys without re-ducing SCC resistance.Herein,a nanostructured Al-5Mg-3 Zn alloy with a good yield strength of 336 MPa and good elongation was successfully produced.By dynamic plastic deformation and appropriate anneal-ing treatment,near-equiaxed nanograins were introduced in the nanostructured Al-5Mg-3 Zn alloy with a high proportion(71%)of the low-angle grain boundary.TEM statistical investigations show that the pre-cipitation of active T’phase at GBs has been greatly suppressed in the nanostructured Al-5Mg-3 Zn alloy at sensitized conditions,and the area fraction of GB precipitates is reduced from 72%to 21%,which sig-nificantly decreases the SCC susceptibility.This study provides guidance for developing advanced Al-Mg alloy with high SCC resistance.展开更多
The strength of traditional Al-Mg alloys primarily depends on cold deformation and increasing Mg content,but it can become susceptible to stress corrosion cracking(SCC)when the Mg content is high(>3 wt.%).Simultane...The strength of traditional Al-Mg alloys primarily depends on cold deformation and increasing Mg content,but it can become susceptible to stress corrosion cracking(SCC)when the Mg content is high(>3 wt.%).Simultaneous optimizing strength and SCC resistance in Al-Mg alloys is challenging.This study introduces a nanostructured Al-10Mg(10 wt.%)alloy with improved strength and SCC resistance by dynamic plastic deformation and optimized annealing.The as-deformed sample exhibits a nano-scaled lamellar structure.With rising annealing temperatures,structure size of the alloy increases while dislocation density decreases,transitioning lamellar to equiaxed grains.Nanostructured Al-10Mg alloys annealed at 250°C exhibit superior mechanical properties and reduced SCC susceptibility at sensitization state.The high fraction of low-angle grain boundaries with a reduction in dislocation density can effectively suppress the nucleation and growth of grain boundary precipitates(GBPs)during sensitization,thereby maintaining a relatively low GBPs coverage.The results provide guidance for designing Al-Mg alloys that are stronger and more resistant to SCC with higher Mg content.展开更多
基金This research was financially supported by the National Nat-ural Science Foundation of China(Grant No.52171088)the Young Elite Scientists Sponsorship Program by CAST(grant No.2022QNRC001).We thank X.Si for assistance in sample prepara-tion.
文摘The strength of traditional Al-Mg alloys is relatively low because it mainly relies on solid solution strengthening.Adding a third component to form precipitation can improve their strength,but it usually leads to high-stress corrosion cracking(SCC)sensitivity due to the formation of high-density precipitates at grain boundaries(GBs).So far,it is still challenging to improve the strength of Al-Mg alloys without re-ducing SCC resistance.Herein,a nanostructured Al-5Mg-3 Zn alloy with a good yield strength of 336 MPa and good elongation was successfully produced.By dynamic plastic deformation and appropriate anneal-ing treatment,near-equiaxed nanograins were introduced in the nanostructured Al-5Mg-3 Zn alloy with a high proportion(71%)of the low-angle grain boundary.TEM statistical investigations show that the pre-cipitation of active T’phase at GBs has been greatly suppressed in the nanostructured Al-5Mg-3 Zn alloy at sensitized conditions,and the area fraction of GB precipitates is reduced from 72%to 21%,which sig-nificantly decreases the SCC susceptibility.This study provides guidance for developing advanced Al-Mg alloy with high SCC resistance.
基金financially supported by the National Natural Science Foundation of China(No.52171088).We thank X.Si for assistance in sample preparation.
文摘The strength of traditional Al-Mg alloys primarily depends on cold deformation and increasing Mg content,but it can become susceptible to stress corrosion cracking(SCC)when the Mg content is high(>3 wt.%).Simultaneous optimizing strength and SCC resistance in Al-Mg alloys is challenging.This study introduces a nanostructured Al-10Mg(10 wt.%)alloy with improved strength and SCC resistance by dynamic plastic deformation and optimized annealing.The as-deformed sample exhibits a nano-scaled lamellar structure.With rising annealing temperatures,structure size of the alloy increases while dislocation density decreases,transitioning lamellar to equiaxed grains.Nanostructured Al-10Mg alloys annealed at 250°C exhibit superior mechanical properties and reduced SCC susceptibility at sensitization state.The high fraction of low-angle grain boundaries with a reduction in dislocation density can effectively suppress the nucleation and growth of grain boundary precipitates(GBPs)during sensitization,thereby maintaining a relatively low GBPs coverage.The results provide guidance for designing Al-Mg alloys that are stronger and more resistant to SCC with higher Mg content.
