Influence of Excess Volumes Induced by Re and W on Dislocation Motion and Creep in Ni-Base Single Crystal Superalloys: A 3D Discrete Dislocation Dynamics Study

A comprehensive 3D discrete dislocation dynamics model for Ni-base single crystal superalloys was used to investigate the influence of excess volumes induced by solute atoms Re and W on dislocation motion and creep under different tensile loads at 850 ° C. The solute atoms were distributed homogeneously only in γ matrix channels. Their excess volumes due to the size difference from the host Ni were calculated by density functional theory. The excess volume affected dislocation glide more strongly than dislocation climb. The relative positions of dislocations and solute atoms determined the magnitude of back stresses on the dislocation motion. Without diffusion of solute atoms, it was found that W with a larger excess volume had a stronger strengthening effect than Re. With increasing concentration of solute atoms, the creep resistance increased. However, a low external stress reduced the influence of different excess volumes and different concentrations on creep.

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Modeling dislocation cutting the precipitate in nickel-based single crystal superalloy via the discrete dislocation dynamics with SISF dissociation scheme

Computational Materials Science ◽

10.1016/j.commatsci.2013.02.026 ◽

2013 ◽

Vol 75 ◽

pp. 52-59 ◽

Cited By ~ 22

Author(s):

Hui Yang ◽

Zhenhuan Li ◽

Minsheng Huang

Keyword(s):

Single Crystal ◽

Dislocation Dynamics ◽

Single Crystal Superalloy ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation

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Influence of rafted microstructures on creep in Ni-base single crystal superalloys: a 3D discrete dislocation dynamics study

Modelling and Simulation in Materials Science and Engineering ◽

10.1088/1361-651x/ab5e40 ◽

2019 ◽

Vol 28 (2) ◽

pp. 025001

Author(s):

Siwen Gao ◽

Muhammad Adil Ali ◽

Alexander Hartmaier

Keyword(s):

Single Crystal ◽

Dislocation Dynamics ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation

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Influence of Initial Defects on the Mechanical Properties of Single Crystal Copper: Discrete Dislocation Dynamics Study

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.627 ◽

2018 ◽

Vol 913 ◽

pp. 627-635

Author(s):

Ming Yi Zhang ◽

Min Zhong ◽

Shuai Yuan ◽

Jing Song Bai ◽

Ping Li

Keyword(s):

Dislocation Density ◽

Single Crystal ◽

Mechanical Response ◽

Three Dimensional ◽

Dislocation Dynamics ◽

Single Crystal Copper ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation ◽

Stress Curve ◽

Initial Dislocation Density

In this paper, three dimensional discrete dislocation dynamics method was used to quantitatively investigate the influence of initial defects on mechanical response of single crystal copper. Both the irradiation defects (interstitial loops) and random dislocation lines with different densities are considered. The simulation results demonstrate that the yield strength of single crystal copper is higher with higher initial dislocation density and higher interstitial loop density. Dislocation density increases quickly by nucleation and multiplication and microbands are formed during plastic deformation when only the random dislocation lines are initially considered. Characteristics of microbands show excellent agreement with experiment results. Dislocation multiplication is suppressed in the presence of interstitial loops, and junctions and locks between dislocations and interstitial loops are formed. Dislocation density evolution shows fluctuation accompanied with strain-stress curve fluctuation.

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Discrete dislocation sim ulation of thin film plasticit y

MRS Proceedings ◽

10.1557/proc-673-p2.3 ◽

2001 ◽

Vol 673 ◽

Cited By ~ 5

Author(s):

B. von Blanckenhagen ◽

P. Gumbsch ◽

E. Arzt

Keyword(s):

Thin Film ◽

Dislocation Motion ◽

Source Size ◽

Dislocation Dynamics ◽

Polycrystalline Thin Film ◽

Confined Geometry ◽

Free Standing ◽

Capping Layer ◽

Discrete Dislocation Dynamics ◽

Discrete Dislocation

ABSTRACTA discrete dislocation dynamics sim ulation is used to investigate dislocation motion in the confined geometry of a polycrystalline thin film. The repeated activ ation of a Frank-Read source is sim ulated. The stress to activate the sources and to initiate plastic fiow is significantly higher than predicted by models where the dislocations extend o ver the entire film thic kness. An efiective source size, which scales with the grain dimensions, yields fiow stresses in reasonable agreemen t with experimen ts. The infiuence of dislocations deposited at interfaces is investigated by comparing calculations for a film sandwic hed between a substrate and a capping layer with those for a free standing film.

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