As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stor...As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.展开更多
The exfoliation corrosion behavior of a novel Al-Li alloy treated by T6- and T8-peak ageing was studied by electrochemical impedance spectroscopy(EIS) technique. The surface morphology of corroded samples was examined...The exfoliation corrosion behavior of a novel Al-Li alloy treated by T6- and T8-peak ageing was studied by electrochemical impedance spectroscopy(EIS) technique. The surface morphology of corroded samples was examined by scanning electron microscope(SEM). The microstructure of un-corroded samples was observed by transmission electron microscope(TEM). At early stage of immersion in EXCO, EIS plots of the two differently processed samples are composed of a capacitive arc in the high frequency range and an inductive loop in the low frequency range. Inductive loop disappears with the increasing of immersion time and two capacitive arcs appear. T6-treated alloy has higher exfoliation susceptibility than T8-treated one, suggested by different exfoliation starting time, which is 23 h and 27 h respectively. T1 phase and equilibrium precipitate at the grain boundary of T6-treated alloy are larger in amount and size than those of T8-treated alloy. This is the main reason for the higher exfoliation susceptibility of T6-treated alloy.展开更多
Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenc...Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenched, and beforetheformationofδ’ phasethereexitscontinuous phasetransformation processes, namely ordering ,spinodal de composition and both coexistence. Gunier Preston zone was not found in the aging process ofthestudied alloy.展开更多
The composition, morphology, crystalline structure and formation and evolution of X phase in a Cu 12.3Al 2Ni 2Mn 1Ti alloy were studied. The results show that the X phase is a Ti rich phase with atomic ratio of (Cu+Ni...The composition, morphology, crystalline structure and formation and evolution of X phase in a Cu 12.3Al 2Ni 2Mn 1Ti alloy were studied. The results show that the X phase is a Ti rich phase with atomic ratio of (Cu+Ni)∶ Ti∶Al=2∶1∶1 and DO 3 or L2 1 structure; it is directly formed in the liquid phase by crystallization in the process of solidification of the alloy; there forms free particle X phase through the progressive dissolution and breakdown of the inter dendritic microstructure in the following homogenization process. The X phase has three different morphologies, i.e. X L, X LS and X S, whose contents in the matrix rely on the heat treatment conditions. [展开更多
基金support from the National Science Foundation of China (No.51971249)the Natural Science Foundation of Shandong Province,China (No.ZR2020KE012)the Science and Technology Planning Project of Longkou City,China (No.2021KJJH025).
基金the project of the Czech Science Foundation (No.20-19170S)the German Research Foundation (Deutsche Forschungsgemeinschaft (DFG))for financial support within the scope of project (No.SCHA 1484/46-1).
基金supports from the National Natural Science Foundation of China(Nos.52371065,52001128)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637)。
文摘As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.
基金Projects(2019YFA0708802, 2020YFA0711104) supported by the National Key R&D Program of ChinaProject(U21B6004) supported by the National Natural Science Foundation of ChinaProject(2021GK1040) supported by Major Project of Scientific Innovation of Hunan Province,China。
文摘The exfoliation corrosion behavior of a novel Al-Li alloy treated by T6- and T8-peak ageing was studied by electrochemical impedance spectroscopy(EIS) technique. The surface morphology of corroded samples was examined by scanning electron microscope(SEM). The microstructure of un-corroded samples was observed by transmission electron microscope(TEM). At early stage of immersion in EXCO, EIS plots of the two differently processed samples are composed of a capacitive arc in the high frequency range and an inductive loop in the low frequency range. Inductive loop disappears with the increasing of immersion time and two capacitive arcs appear. T6-treated alloy has higher exfoliation susceptibility than T8-treated one, suggested by different exfoliation starting time, which is 23 h and 27 h respectively. T1 phase and equilibrium precipitate at the grain boundary of T6-treated alloy are larger in amount and size than those of T8-treated alloy. This is the main reason for the higher exfoliation susceptibility of T6-treated alloy.
文摘Theinitialstageofagingtransformationin Al 2 27% Li 2 68 % Cu 0 11% Zr 0 13% Ceal loy at100℃wasstudied by meansof x ray diffraction.It wasconcludedthatordering of Liatom happens whenthealloyissolution treated andquenched, and beforetheformationofδ’ phasethereexitscontinuous phasetransformation processes, namely ordering ,spinodal de composition and both coexistence. Gunier Preston zone was not found in the aging process ofthestudied alloy.
文摘The composition, morphology, crystalline structure and formation and evolution of X phase in a Cu 12.3Al 2Ni 2Mn 1Ti alloy were studied. The results show that the X phase is a Ti rich phase with atomic ratio of (Cu+Ni)∶ Ti∶Al=2∶1∶1 and DO 3 or L2 1 structure; it is directly formed in the liquid phase by crystallization in the process of solidification of the alloy; there forms free particle X phase through the progressive dissolution and breakdown of the inter dendritic microstructure in the following homogenization process. The X phase has three different morphologies, i.e. X L, X LS and X S, whose contents in the matrix rely on the heat treatment conditions. [