Interactions between butterfly-like prismatic dislocation loop pairs and planar defects in Ni3Al
Zhiwei Zhang1, Qiang Fu2, Jun Wang3
1State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China. wangjun@lnm.imech.ac.cn and School of Engineering Science, University of Chinese Academy of Sciences, Beijing, 100049, China.
Physical Chemistry Chemical Physics : PCCP
|April 22, 2021
Summary
Planar defects in Ni3Al materials hinder prismatic dislocation loop movement, acting as a hardening mechanism. Twinning boundaries are the most effective impediment, offering insights for advanced material design.
Area of Science:
- Materials Science
- Nanotechnology
- Computational Materials Science
Background:
- Understanding material deformation mechanisms is crucial for designing advanced materials.
- Dislocation interactions with planar defects significantly influence mechanical properties.
Purpose of the Study:
- To investigate the atomistic interactions between prismatic dislocation loops and planar defects in Ni3Al.
- To elucidate the hardening effects and mechanisms governing these interactions.
Main Methods:
- Atomistic simulations using molecular dynamics (MD).
- Nanoindentation simulations were employed to observe defect behavior.
Main Results:
- Prismatic dislocation loops in Ni3Al were observed to form in pairs with a butterfly-like shape.
- Planar defects, including twinning boundaries, antiphase boundaries, and stacking faults, were found to impede dislocation loop movement.
- Twinning boundaries exhibited the strongest impediment, while antiphase boundaries showed the weakest.
Conclusions:
- Planar defects play a significant role in the hardening of Ni3Al by blocking dislocation loop motion.
- The findings offer insights into the nanostructured design of materials with enhanced mechanical properties.
Related Concept Videos
02:33Lattice Centering and Coordination Number
10.6K
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
Types of Unit Cells
Imagine taking a large number of identical...
10.6K
02:37Metallic Solids
19.8K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
19.8K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.8K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
45.8K
02:42Valence Bond Theory
10.0K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
10.0K
02:55Exceptions to the Octet Rule
33.1K
Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:
33.1K
02:42Ionic Crystal Structures
16.0K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
16.0K