Strain gradient plasticity modeling of nanoindentation of additively manufactured stainless steel

Ding, Kunqing; Zhang, Yin; Birnbaum, Andrew J.; Michopoulos, John G.; Zhu, Ting

doi:10.1016/j.eml.2021.101503

Cited by 9 publications

(9 citation statements)

References 17 publications

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“…Similar as-printed dislocation structures are also observed in AM metals [7,8] and alloys without chemical cells [9]. These as-printed dislocation cells and structures hinder dislocation glide during plastic deformation, thereby affecting the mechanical properties of AM metallic materials [9,10].…”

Section: Introductionsupporting

confidence: 55%

“…Previous studies in the literature [9,10] and DDD simulations in section 2 indicate that the 'as-printed dislocation cells' in AM metallic materials can give rise to substantial microscale internal stresses in both initial undeformed and plastically deformed samples, thereby affecting the mechanical properties of these alloys. To gain an in-depth understanding of the mechanics of as-printed dislocation cells, we develop a crystal plasticity (CP) model that accounts for different sources of microscale internal stresses in AM 316L stainless steel by focusing on their back stress components.…”

Section: Modeling Of Back Stresses In Am Stainless Steelmentioning

confidence: 94%

“…In equation (10), ρ+ i is the rate of increase of dislocations in pile-ups due to the operation of FR sources in cell interiors. Following Mecking and Kocks [24], we express this hardening process by…”

Section: Crystal Plasticity Modelmentioning

confidence: 99%

“…In equation (10), ρ− i is the rate of decrease of dislocations in pile-ups due to plastic relaxation in cell walls. Such plastic relaxation is driven by the forward stresses in the cell walls, causing forest cutting and/or annihilation of dislocation dipoles therein [12].…”

Section: Crystal Plasticity Modelmentioning

confidence: 99%

See 3 more Smart Citations

Modeling of microscale internal stresses in additively manufactured stainless steel

Zhang

Ding

et al. 2022

Modelling Simul. Mater. Sci. Eng.

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Additively manufactured (AM) metallic materials often comprise as-printed dislocation cells inside grains. These dislocation cells can give rise to substantial microscale internal stresses in both initial undeformed and plastically deformed samples, thereby affecting the mechanical properties of AM metallic materials. Here we develop models of microscale internal stresses in AM stainless steel by focusing on their back stress components. Three sources of microscale back stresses are considered, including the printing and deformation-induced back stresses associated with as-printed dislocation cells as well as the deformation-induced back stresses associated with grain boundaries. We use a three-dimensional discrete dislocation dynamics model to demonstrate the manifestation of printing-induced back stresses. We adopt a dislocation pile-up model to evaluate the deformation-induced back stresses associated with as-printed dislocation cells. The extracted back stress relation from the pile-up model is incorporated into a crystal plasticity model that accounts for the other two sources of back stresses as well. The crystal plasticity finite element simulation results agree with the experimentally measured tension-compression asymmetry and macroscopic back stress, the latter of which represents the effective resultant of microscale back stresses of different origins. Our results provide an in-depth understanding of the origins and evolution of microscale internal stresses in AM metallic materials.

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Section: Introductionsupporting

confidence: 55%

Section: Modeling Of Back Stresses In Am Stainless Steelmentioning

confidence: 94%

Section: Crystal Plasticity Modelmentioning

confidence: 99%

Section: Crystal Plasticity Modelmentioning

confidence: 99%

See 2 more Smart Citations

Modeling of microscale internal stresses in additively manufactured stainless steel

Zhang

Ding

et al. 2022

Modelling Simul. Mater. Sci. Eng.

Self Cite

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“…Moreover, the method of instrumented nanoindentation is also used to study and evaluate the stress-strain state of the workpiece's subsurface layers. Using nanoindentation, the strain degree of additively manufactured stainless steels [30], Fe-ion-irradiated steels [31], structural steels under tensile loads [32], the strain degree, fracture process, and microstructure changes of austenitic steels [33,34] and others have been evaluated. Wagner et al studied the behavior of non-metallic particles in 42CrMo4 alloyed steel [35].…”

Section: Methods For the Determination Of Machined Layers Mechanical ...mentioning

confidence: 99%

Mechanical Characteristics Generation in the Workpiece Subsurface Layers through Cutting

Storchak

2023

Crystals

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The cutting process generates specific mechanical characteristics in the subsurface layers of the shaped parts. These characteristics have a decisive influence on the working properties and product durability of these parts. The orthogonal cutting process of structural heat-treated steel’s effect on the mechanical properties of the machined subsurface layers was evaluated by instrumented the nanoindentation method and sclerometry (scratch) method. As a result of this study, the relationship between the specific work in the tertiary cutting zone and the total deformation work during indenter penetration during the instrumented nanoindentation was established. The dependence of the indenter penetration depth during sclerometry of the machined subsurface layers of the workpiece was also studied. The orthogonal cutting process was carried out at different cutting speeds and tool rake angles. The cutting speed increase and the increase in the tool rake angle cause an increase in the indenter penetration work during the instrumented nanoindentation and an increase in the maximum indenter penetration depth during sclerometry. Simultaneously, the measured microhardness of the machined surfaces decreases with both an increase in cutting speed and an increase in the tool rake angle.

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Mechanics of gradient nanostructured metals

Zhang,

Cheng,

Zhu

et al. 2024

Journal of the Mechanics and Physics of Solids

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Strain gradient plasticity modeling of nanoindentation of additively manufactured stainless steel

Cited by 9 publications

References 17 publications

Modeling of microscale internal stresses in additively manufactured stainless steel

Modeling of microscale internal stresses in additively manufactured stainless steel

Mechanical Characteristics Generation in the Workpiece Subsurface Layers through Cutting

Mechanics of gradient nanostructured metals

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