In this paper,the property degradation micromechanism of Al-5.10Cu-0.65 Mg-0.8Mn(wt%)alloy induced by 0.5 wt%Fe minor addition was revealed by atomic-scale scanning transmission electron microscopy and energy-dispersi...In this paper,the property degradation micromechanism of Al-5.10Cu-0.65 Mg-0.8Mn(wt%)alloy induced by 0.5 wt%Fe minor addition was revealed by atomic-scale scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy coupled with first-principles calculations.The results show that the Fe minor addition to the Al-Cu-Mg-Mn alloy leads to a slight reduction of grain size and the formation of coarse Al7Cu2Fe constituent particles.Fe tends to segregate into the T-phase dispersoids,θ'-,and S-phase precipitates by preferentially occupying Cu or Mn sites in these phase structures.The apparent Fe segregation contributes to an increase in stiffness of the T-phase and S-phase but decreased stiffness of theθ'phase.Formation of the coarse Al7Cu2Fe constituent particles and decreased stiffness of main precipitatesθ'containing Fe result in the degraded strength of the Al-Cu-Mg-Mn-Fe alloy.Further study reveals that corrosion resistance degradation of the Al-Cu-Mg-Mn-Fe alloy is associated with the increased width of precipitation free zones and consecutive grain boundary precipitates.The obtained results have significant implications for the usage of recycled Al alloys and the potential design strategies of high-performance alloys containing Fe.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U20A20274 and 52061003)the Natural Science Foundation of Yunnan Province(No.202301AT070209)the Science and Technology Major Project of Yunnan Province(No.202102AG050017).
文摘In this paper,the property degradation micromechanism of Al-5.10Cu-0.65 Mg-0.8Mn(wt%)alloy induced by 0.5 wt%Fe minor addition was revealed by atomic-scale scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy coupled with first-principles calculations.The results show that the Fe minor addition to the Al-Cu-Mg-Mn alloy leads to a slight reduction of grain size and the formation of coarse Al7Cu2Fe constituent particles.Fe tends to segregate into the T-phase dispersoids,θ'-,and S-phase precipitates by preferentially occupying Cu or Mn sites in these phase structures.The apparent Fe segregation contributes to an increase in stiffness of the T-phase and S-phase but decreased stiffness of theθ'phase.Formation of the coarse Al7Cu2Fe constituent particles and decreased stiffness of main precipitatesθ'containing Fe result in the degraded strength of the Al-Cu-Mg-Mn-Fe alloy.Further study reveals that corrosion resistance degradation of the Al-Cu-Mg-Mn-Fe alloy is associated with the increased width of precipitation free zones and consecutive grain boundary precipitates.The obtained results have significant implications for the usage of recycled Al alloys and the potential design strategies of high-performance alloys containing Fe.
