The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain ...The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain direction onthe microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain directioncan modify microstructure of Ti-25Al-10～12Nb (at. pct) alloy during α_2→O-phase transformation effectively andfull laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along thedirection 30°away from the α_2 phase <1010> in magnitude equivalent to the stress-free transformation strain. Thesimulation also shows that not only the magnitude of applied strain but also the applied strain direction influencesthe O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.展开更多
Segregation of solutes/impurities in the interfaces plays a decisive role in material performances.However,the segregation of solutes/impurities remains elusive due to the diversity of interfacial structures.Here,in a...Segregation of solutes/impurities in the interfaces plays a decisive role in material performances.However,the segregation of solutes/impurities remains elusive due to the diversity of interfacial structures.Here,in a Mg-Nd-Mn ternary model system,two ordered novel two-dimensional(2D)interfacial superstructures formed by periodic segregation of solute atoms in special symmetric and asymmetric tilt grain boundaries(GBs)have been systematically investigated.Z-Contrast high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)observations provided the atomic-level details on how solute atoms were arranged on these special partially coherent tilt GBs.The strained conditions of each atomic site at the tilt GBs were accurately reproduced by molecular dynamics(MD)simulations plus Voronoi analysis,and the rationality of solute segregation in each atomic-site was evaluated carefully based on the first-principles calculations.These findings expand our knowledge of solute/impurity segregation behaviors in the interfaces,especially the co-segregation behaviors in multi-component materials.展开更多
文摘The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain direction onthe microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain directioncan modify microstructure of Ti-25Al-10～12Nb (at. pct) alloy during α_2→O-phase transformation effectively andfull laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along thedirection 30°away from the α_2 phase <1010> in magnitude equivalent to the stress-free transformation strain. Thesimulation also shows that not only the magnitude of applied strain but also the applied strain direction influencesthe O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.
基金financially supported by the National Key Research and Development Program of China(No.2021YFB3701002)the National Natural Science Foundation of China(No.52101129)the Fundamental Research Funds for the Central Universities(Nos.N2202013 and N2007011).
文摘Segregation of solutes/impurities in the interfaces plays a decisive role in material performances.However,the segregation of solutes/impurities remains elusive due to the diversity of interfacial structures.Here,in a Mg-Nd-Mn ternary model system,two ordered novel two-dimensional(2D)interfacial superstructures formed by periodic segregation of solute atoms in special symmetric and asymmetric tilt grain boundaries(GBs)have been systematically investigated.Z-Contrast high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)observations provided the atomic-level details on how solute atoms were arranged on these special partially coherent tilt GBs.The strained conditions of each atomic site at the tilt GBs were accurately reproduced by molecular dynamics(MD)simulations plus Voronoi analysis,and the rationality of solute segregation in each atomic-site was evaluated carefully based on the first-principles calculations.These findings expand our knowledge of solute/impurity segregation behaviors in the interfaces,especially the co-segregation behaviors in multi-component materials.
