The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely rel...The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely related to the alloy compositions. The effect of hot-working process on the room tem perature ductility is remarkable, not only resulting in an appreciable improvement of compressive properties but also showing a 0.28% plastic strain in tensile test. The SISF dissociation of a < 110>dislocations on {111} planes was found at room temperature. The determined dissociation scheme is consistent with the mechanical behaviour of these alloys in the lower temperature region.展开更多
The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning tra...The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy and first-principles cal-culations.The heat treatment initially produces a pure L1_(2)-Al_(3)Zr microstructure,allowing for about 13%Cu to be incorporated in the dispersoid.Cu incorporation increases the energy barrier for anti-phase boundary(APB)activation,thus stabilizing the L1_(2)structure.Additional heating leads to a Cu-induced“branched”path for the L1_(2)structural transformation,with the latter process accelerated once the first APB has been created.Cu atoms may either(i)be repelled by the APBs,promoting the transformation to a Cu-poor D0_(23) phase,or(ii)they may segregate at one Al-Zr layer adjacent to the APB,promoting a transformation to a new thermodynamically favored phase,Al4 CuZr,formed when these segregation layers are periodically arranged.Theoretical studies suggest that the branching of the L1_(2)transformation path is linked to the speed at which an APB is created,with Cu attraction triggered by a comparatively slow process.This unexpected transformation behavior of the L1_(2)-Al_(3)Zr phase opens a new path to un-derstanding,and potentially regulating the Al_(3)Zr dispersoid evolution for high temperature applications.展开更多
文摘The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely related to the alloy compositions. The effect of hot-working process on the room tem perature ductility is remarkable, not only resulting in an appreciable improvement of compressive properties but also showing a 0.28% plastic strain in tensile test. The SISF dissociation of a < 110>dislocations on {111} planes was found at room temperature. The determined dissociation scheme is consistent with the mechanical behaviour of these alloys in the lower temperature region.
基金supported by the National Key Research and Development Program(No.2020YFA0405900)the National Natural Science Foundation of China(Grant No.52371111 and U2141215)the Natural Science Foundation of Jiangsu Province(No.BE2022159).
文摘The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy and first-principles cal-culations.The heat treatment initially produces a pure L1_(2)-Al_(3)Zr microstructure,allowing for about 13%Cu to be incorporated in the dispersoid.Cu incorporation increases the energy barrier for anti-phase boundary(APB)activation,thus stabilizing the L1_(2)structure.Additional heating leads to a Cu-induced“branched”path for the L1_(2)structural transformation,with the latter process accelerated once the first APB has been created.Cu atoms may either(i)be repelled by the APBs,promoting the transformation to a Cu-poor D0_(23) phase,or(ii)they may segregate at one Al-Zr layer adjacent to the APB,promoting a transformation to a new thermodynamically favored phase,Al4 CuZr,formed when these segregation layers are periodically arranged.Theoretical studies suggest that the branching of the L1_(2)transformation path is linked to the speed at which an APB is created,with Cu attraction triggered by a comparatively slow process.This unexpected transformation behavior of the L1_(2)-Al_(3)Zr phase opens a new path to un-derstanding,and potentially regulating the Al_(3)Zr dispersoid evolution for high temperature applications.
