Dislocation-grain boundary interactions in Ni3Al; effects of structure and chemistry

Lee, T.C; Subramanian, Raja; Robertson, I. M.; Birnbaum, H.K.

doi:10.1016/0956-716x(91)90398-k

Cited by 12 publications

(2 citation statements)

References 18 publications

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“…A number of investigators [41-431 believe and have shown that the boron causes a local disordering along the grain boundaries so that slip can pass into and through grain boundaries with relative ease. Other workers [8,30,[44][45][46] believe and have shown that the boron does not cause a significant degree of disorder. Several possible explanations for increased ductility without significant disorder have been proposed.…”

Section: Llb Application Of the Eam To Boundaries In Ni3almentioning

confidence: 95%

Interfacial studies using the EAM and MEAM

Angelo

Baskes

1997

Interface Sci

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Abstract.A brief review of our current applications of the Embedded Atom Method (EAM) and Modified Embedded Atom Method (MEAM) is given in this paper as they relate to the structure of interfaces in materials. The EAM is used to consider the effect of hydrogen on the structure and properties of boundaries in nickel and nickel aluminide (Ni3A1). In both cases hydrogen segregates to the boundary causing a reduction in the cohesive strength. Next, the EAM is applied to describe the equilibrium and dynamic structure of a dissociated Z3(112) boundary in copper. Comparison is made to recent experimental observations which show good agreement with the modeled behavior. Finally, the MEAM is used to help understand the properties of both the nickel/silicon and aluminum/sapphire systems.

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Section: Llb Application Of the Eam To Boundaries In Ni3almentioning

confidence: 95%

Interfacial studies using the EAM and MEAM

Angelo

Baskes

1997

Interface Sci

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“…Early work by Robertson and coworkers [3][4][5][6][7] established experimentally the conditions for slip transfer across high-angle and random grain boundaries during the early stages of quasi-static loading. Specifically, it was determined that the slip transfer process was governed by competition between the slip system experiencing the maximum local resolved shear stress (applied stress + dislocation pile-up contribution) and the change in energy of the grain boundary as a consequence of the dislocation absorption and emission process.…”

Section: Modelingmentioning

confidence: 99%

Determining the mechanical constitutive properties of metals as a function of strain rate and temperature: A combined experimental and modeling approach; Progress Report for 2004

Robertson¹,

Beaudoin²,

Lambros³

2005

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Determining the mechanical constitutive properties of metals as a function of strain rate and temperature: A combined experimental and modeling approach Progress report for 2004Development and validation of constitutive models for polycrystalline materials subjected to high strain rate loading over a range of temperatures are needed to predict the response of engineering materials to in-service type conditions (foreign object damage, high-strain rate forging, high-speed sheet forming, deformation behavior during forming, response to extreme conditions, etc.). To account accurately for the complex effects that can occur during extreme and variable loading conditions, requires significant and detailed computational and modeling efforts. These efforts must be closely coupled with precise and targeted experimental measurements that not only verify the predictions of the models, but also provide input about the fundamental processes responsible for the macroscopic response. Achieving this coupling between modeling and experimentation is the guiding principle of this program. Specifically, this program seeks to bridge the length scale between discrete dislocation interactions with grain boundaries and continuum models for polycrystalline plasticity. Achieving this goal requires incorporating these complex dislocation-interface interactions into the well-defined behavior of single crystals. Despite the widespread study of metal plasticity, this aspect is not well understood for simple loading conditions, let alone extreme ones. Our experimental approach includes determining the high-strain rate response as a function of strain and temperature with post-mortem characterization of the microstructure, quasi-static testing of predeformed material, and direct observation of the dislocation behavior during reloading by using the in situ transmission electron microscope deformation technique. These experiments will provide the basis for development and validation of physically-based constitutive models, which will include dislocation-grain boundary interactions for polycrystalline systems. One aspect of the program will involve the direct observation of specific mechanisms of micro-plasticity, as these will indicate the boundary value problem that should be addressed. This focus on the pre-yield region in the quasi-static effort (the elasto-plastic transition) is also a tractable one from an experimental and modeling viewpoint. In addition, our approach will minimize the need to fit model parameters to experimental data to obtain convergence. These are critical steps to reach the primary objective of simulating and modeling material performance under extreme loading conditions. To achieve these goals required assembling a multidisciplinary team, see Table 1, with key collaborators at the National Laboratories. One of the major issues for the team members was to learn about the expertise available and how to communicate across disciplines. The communication issue is a challenging one and is being addressed in part with weekly ...

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Dislocations Nucleation and Interaction with Grain Boundaries in a Polycrystalline Nickel Base Superalloy

Messé

Rae

2016

Superalloys 2016

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Dislocation-grain boundary interactions in Ni3Al; effects of structure and chemistry

Cited by 12 publications

References 18 publications

Interfacial studies using the EAM and MEAM

Interfacial studies using the EAM and MEAM

Determining the mechanical constitutive properties of metals as a function of strain rate and temperature: A combined experimental and modeling approach; Progress Report for 2004

Dislocations Nucleation and Interaction with Grain Boundaries in a Polycrystalline Nickel Base Superalloy

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