Thermodynamically stable and ultra-thin “phase” at the interface, known as complexions, can significantly improve the mechanical properties of nanolayered composites. However, the effect of complexions features (e.g...Thermodynamically stable and ultra-thin “phase” at the interface, known as complexions, can significantly improve the mechanical properties of nanolayered composites. However, the effect of complexions features (e.g., crystalline orientation, crystalline structure and amorphous composition) on the plastic deformation remains inadequately investigated, and the correlation with the plastic transmission and mechanical response has not been fully established. Here, using atomistic simulations, we elucidate the different complexions-dominated plastic transmission and mechanical response. Complexions can alter the preferred slip system of dislocation nucleation, depending on the Schmid factor and interface structure. After nucleation, the dislocation density exhibits an inverse correlation with the stress magnitude, because the number of dislocations influences the initiation of plastic deformation and determines the stress release. For crystalline complexions with different structures and orientations, the ability of dislocation transmission is mainly dependent on the continuity of the slip system. The plastic transmission can easily proceed and exhibits relatively low flow stress when the slip system is well-aligned. In the case of amorphous complexions with different compositions, compositional variations impact the atomic percentage of shear transformation zones after loading, resulting in different magnitudes of plastic deformation. When smaller plastic deformation is produced, less stress can be released contributing to higher flow stress. These findings reveal the role of the complexions on plasticity behavior and provide valuable insights for the design of nanolayered composites.展开更多
The nanolaminated materials generally exhibit poor plasticity due to the fast onset of shear instability.Engineering interface structure is an eff ective approach for enhancing plasticity via postponing or suppressing...The nanolaminated materials generally exhibit poor plasticity due to the fast onset of shear instability.Engineering interface structure is an eff ective approach for enhancing plasticity via postponing or suppressing the shear instability.Here,we introduce 4 nm thick CuNb 3D amorphous interface layers and Nb 3D crystalline interface layers in Cu nanolaminated materials,respectively.In situ micro-pillar compression tests show that samples with crystalline interface layers exhibit shear instability,while the samples with amorphous interface layers display uniform deformation.Since the plastic deformation of the singlecrystal crystalline interface layer is anisotropic,except for well-aligned slip systems,dislocations on other slip systems have a poor ability to transmit the 3D crystalline interface layer,leading to localized dislocations pileups and shear instability.In contrast,the amorphous interface layer which is plastically isotropic accommodates dislocations from arbitrary slip systems of the matrix,which can alleviate the stress concentrations at the interface,and thus suppresses the shear instability.展开更多
1.Introduction High strength and large deformability are greatly desirable for advanced structural metallic materials.Typically strengthening methods in crystalline materials rely on controlling the generation,propaga...1.Introduction High strength and large deformability are greatly desirable for advanced structural metallic materials.Typically strengthening methods in crystalline materials rely on controlling the generation,propagation,and intersection of dislocations by introducing various internal defects[1-4].展开更多
基金supported by the National Natural Science Foundation of China(Nos.U23A20543,52071124)the Natural Science Foundation of the Hebei Province(No.E2021202135).
文摘Thermodynamically stable and ultra-thin “phase” at the interface, known as complexions, can significantly improve the mechanical properties of nanolayered composites. However, the effect of complexions features (e.g., crystalline orientation, crystalline structure and amorphous composition) on the plastic deformation remains inadequately investigated, and the correlation with the plastic transmission and mechanical response has not been fully established. Here, using atomistic simulations, we elucidate the different complexions-dominated plastic transmission and mechanical response. Complexions can alter the preferred slip system of dislocation nucleation, depending on the Schmid factor and interface structure. After nucleation, the dislocation density exhibits an inverse correlation with the stress magnitude, because the number of dislocations influences the initiation of plastic deformation and determines the stress release. For crystalline complexions with different structures and orientations, the ability of dislocation transmission is mainly dependent on the continuity of the slip system. The plastic transmission can easily proceed and exhibits relatively low flow stress when the slip system is well-aligned. In the case of amorphous complexions with different compositions, compositional variations impact the atomic percentage of shear transformation zones after loading, resulting in different magnitudes of plastic deformation. When smaller plastic deformation is produced, less stress can be released contributing to higher flow stress. These findings reveal the role of the complexions on plasticity behavior and provide valuable insights for the design of nanolayered composites.
基金financially supported by the National Natural Science Foundation of China(Nos.51771201,52071124)the Key Project of Natural Science Foundation of Hebei(No.E2021202135)+2 种基金the Key Project of Natural Science Foundation of Tianjin(No.20JCZDJC00440)the Central Funds Guiding the Local Science and Technology Development of Hebei Province(No.226Z1001G and 226Z1012G)the Open Research Fund from the State Key Laboratory of Rolling and Automation,Northeastern University,Grant No.:2020RALKFKT002。
文摘The nanolaminated materials generally exhibit poor plasticity due to the fast onset of shear instability.Engineering interface structure is an eff ective approach for enhancing plasticity via postponing or suppressing the shear instability.Here,we introduce 4 nm thick CuNb 3D amorphous interface layers and Nb 3D crystalline interface layers in Cu nanolaminated materials,respectively.In situ micro-pillar compression tests show that samples with crystalline interface layers exhibit shear instability,while the samples with amorphous interface layers display uniform deformation.Since the plastic deformation of the singlecrystal crystalline interface layer is anisotropic,except for well-aligned slip systems,dislocations on other slip systems have a poor ability to transmit the 3D crystalline interface layer,leading to localized dislocations pileups and shear instability.In contrast,the amorphous interface layer which is plastically isotropic accommodates dislocations from arbitrary slip systems of the matrix,which can alleviate the stress concentrations at the interface,and thus suppresses the shear instability.
基金supported by the National Natural Science Foundation of China(Nos.52002109,52071124)the key project of Natural Science Foundation of Tianjin(No.20JCZDJC00440)+2 种基金the key project of Natural Science Foundation of Hebei(No.E2021202135)the Central Funds Guiding the Local Science and Technology Development of Hebei Province(Nos.226Z1001G and 226Z1012G)the Innovation Funding Project for Postgraduate of the Hebei Province(No.GXZZSS2023028).
文摘1.Introduction High strength and large deformability are greatly desirable for advanced structural metallic materials.Typically strengthening methods in crystalline materials rely on controlling the generation,propagation,and intersection of dislocations by introducing various internal defects[1-4].
