Process-induced evolution of prismatic dislocation loop and its effect on mechanical properties

Li, Junye; Dong, Xiwei; Xie, Hongcai; Xu, Chengyu; Liu, Jianhe; Zhang, Jingran

doi:10.1016/j.mtcomm.2022.103754

Cited by 3 publications

(3 citation statements)

References 45 publications

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“…Lomer-Cottrell (L-C) dislocation and Hirth obstruction consisted of two extended dislocations and one stair-rod dislocation or Hirth dislocation, respectively. Te diference between these two forms of sessile dislocation confguration was that the angle between the two stacking faults connected to the stair-rod dislocation was distinct from that connected to the Hirth dislocation (acute and obtuse angle, respectively) [21]. In this study, the Tompson tetrahedron was adopted to describe the dislocation reactions for the FCC lattice structure [29].…”

Section: Subsurface Defect Structurementioning

confidence: 99%

“…Furthermore, due to the interaction among dislocations which occurs by means of dislocation jog, dislocation kink, and cross-slip, various subsurface defects can be generated, thus causing permanent plastic deformation and severely afecting its working life [15], for instance, atomic cluster [16], prismatic dislocation [17], Lomer-Cottrell lock [18], prismatic dislocation loop [19], and stacking fault tetrahedron (SFT) [20]. Li et al [21] carried out nanocutting simulations of c-TiAl alloy under fuid media and analyzed the evolution of the prismatic dislocation loop, subsequently indicating that the formation of subsurface defects led to the work-hardening phenomenon adopting nanoindentation as the characterization method, with the indentation load, surface hardness, and Young's modulus as the evaluation indicators. Liu et al [22] conducted real-time observation of SFT formation and annihilation processes in terms of dislocation reactions.…”

Section: Introductionmentioning

confidence: 99%

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Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Liu,

Wang,

Yang

2023

Nanomaterials and Nanotechnology

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Multigroup large-scalenanocutting models of monocrystalline Cu were established by molecular dynamics simulations to investigate the influence of cutting parameters on the material removal mechanism. The formation and distribution of subsurface defect structures were revealed, and the evolution behavior of the complete prismatic dislocation loop was analyzed in depth. It was demonstrated that the chips and machined surface of monocrystalline Cu were mainly formed under the coupling effect of shearing and extrusion forces. A diamond tool with a larger edge radius or a negative rake angle could produce a noticeable suppression on the chip formation. The corresponding relationship between the location of defect atoms and the distribution of von Mises stress was studied, which indicated that the shear stress would become larger at the subgrain boundaries, dislocation lines, and the amorphous atoms than that in their nearby regions. The complete prismatic dislocation loop was formed by cross-slip between two sets of stacking faults; meanwhile, the generated multiple Lomer–Cottrell locks hindered its movement and promoted the work-hardening phenomenon. These research results are of great theoretical value to enrich the nanocutting mechanism and technology of plastic materials.

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Section: Subsurface Defect Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Liu,

Wang,

Yang

2023

Nanomaterials and Nanotechnology

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“…This approach can track the information at the atomic level and provide a detailed description, essential for understanding the mechanism and behavior of fretting wear in dual-phase TiAl alloys [21][22][23][24][25]. Li et al [26] found that the presence of stepped rods in the prismatic dislocation rings on the subsurface of single-crystal γ-TiAl alloys under the nano-cutting and indentation process impedes the slip of layer dislocations, and the defective structure increases the hardness of the material. A certain degree of elastic recovery of the material occurs due to the release of residual stresses after the nanoindentation process.…”

Section: Introductionmentioning

confidence: 99%

Compression and fretting wear studies of γ/α ₂ duplex TiAl alloys at the nanoscale

Zheng,

Han,

et al. 2024

Phys. Scr.

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The nanofabrication behavior of γ/α2 duplex TiAl alloys by downward pressure followed by reciprocating friction with investigating diamond grinding balls via MD simulation. It was found that a certain number of dislocations in the workpiece was low and the resilience was high during the initial pressing stage, and the number of dislocations increased, the resilience decreased and the plastic deformation capacity was enhanced under continuous pressing. The α2 phase did not deform significantly during the compression process. The presence of the α2 phase increases the overall hardness of the material, and elastic-plastic deformation occurs mainly where the γ phase is present， The endowment layer dislocations generated during the intrinsic stacking fault rebound via the phase boundary to form V-shaped dislocations. During the reciprocating friction of the workpiece, forward friction produces Vshaped dislocations, and reverse friction makes the dislocations disappear. This process results in the forward average friction force being greater than the reverse average friction force. γ/α2 phase boundary has an impeding effect on the downward proliferation of defects, and the existence of the phase boundary makes the temperature transfer appear discontinuous. During friction, the certain number of vacancy atoms in the γ-phase increases and the transition between FCC and HCP occurs.

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Simulation and Experimental Study on Stress Relaxation Response of Polycrystalline γ-TiAl Alloy under Nanoindentation Based on Molecular Dynamics

Li,

Wang,

Liu

et al. 2024

Micromachines

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This study employed nano-indentation technology, molecular dynamics simulation, and experimental investigation to examine the stress relaxation behaviour of a polycrystalline γ-TiAl alloy. The simulation enabled the generation of a load-time curve, the visualisation of internal defect evolution, and the mapping of stress distribution across each grain during the stress relaxation stage. The findings indicate that the load remains stable following an initial decline, thereby elucidating the underlying mechanism of load change during stress relaxation. Furthermore, a nano-indentation test was conducted on the alloy, providing insight into the load variation and stress relaxation behaviour under different loading conditions. By comparing the simulation and experimental results, this study aims to guide the theoretical research and practical application of γ-TiAl alloys.

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Process-induced evolution of prismatic dislocation loop and its effect on mechanical properties

Cited by 3 publications

References 45 publications

Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Compression and fretting wear studies of γ/α ₂ duplex TiAl alloys at the nanoscale

Simulation and Experimental Study on Stress Relaxation Response of Polycrystalline γ-TiAl Alloy under Nanoindentation Based on Molecular Dynamics

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Process-induced evolution of prismatic dislocation loop and its effect on mechanical properties

Cited by 3 publications

References 45 publications

Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Material Removal Mechanism and Evolution of Subsurface Defects during Nanocutting of Monocrystalline Cu

Compression and fretting wear studies of γ/α 2 duplex TiAl alloys at the nanoscale

Simulation and Experimental Study on Stress Relaxation Response of Polycrystalline γ-TiAl Alloy under Nanoindentation Based on Molecular Dynamics

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Compression and fretting wear studies of γ/α ₂ duplex TiAl alloys at the nanoscale