Crystallographic Orientation Dependence of Nitrogen Mass Transport in Austenitic Stainless Steel

Moskaliovienė, Teresa; Galdikas, Arvaidas

doi:10.3390/met10050615

Cited by 5 publications

(20 citation statements)

References 41 publications

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“…This phenomenon implies the occurrence of local stresses, induced by nitrogen concentration gradients, and influences nitrogen transport in the expanded austenite phase. A systematic model for nitrogen transport in ASS that takes into account nitrogen diffusion and stress interaction was proposed in our previous works [26][27][28][29][30][31]. A generalized chemical potential and a diffusive flux are addressed to the freely diffusing nitrogen and according the stress-assisted diffusion model, the relationship between them attains the following form…”

Section: Mass Transport Model-the Coupling Between Nitrogen Stress-assisted Diffusion and Trappingmentioning

confidence: 99%

“…To evaluate the compressive stress and the compositional strain induced by the interstitial atom diffusion in the expanded austenite, a mechanical model recently proposed in our previous work [29,31] was used. This model is based on the Hooke's law and considers elastic anisotropy of ASS.…”

Section: Mass Transport Model-the Coupling Between Nitrogen Stress-assisted Diffusion and Trappingmentioning

confidence: 99%

“…The effect of anisotropic lattice expansion could be explained by the residual compressive stress developed during nitriding which varies as a function of crystalline orientation of the ASS specimen due to the elastically anisotropic nature of austenite [11,22,23]. The elastic field creates an 2 of 13 additional driving force for the nitrogen transport [24][25][26][27][28][29][30][31]. Because of the elastic anisotropy of ASS, the induced internal stresses are dependent on the crystalline orientation and influence of nitrogen penetration depth, which becomes dependent on the crystalline orientation [31].…”

Section: Introductionmentioning

confidence: 99%

“…The elastic field creates an 2 of 13 additional driving force for the nitrogen transport [24][25][26][27][28][29][30][31]. Because of the elastic anisotropy of ASS, the induced internal stresses are dependent on the crystalline orientation and influence of nitrogen penetration depth, which becomes dependent on the crystalline orientation [31].…”

Section: Introductionmentioning

confidence: 99%

“…Surface free energy depends on the orientation of the surface [32] which means that processes on the surface also have an anisotropic nature and influence the anisotropic nature of nitrogen penetration in the volume of austenite. The nitrogen fluxes passing through the surface of different crystalline orientations can be different due to the anisotropic nature of adsorption and heterogeneous chemical reactions on the surface [31].…”

Section: Introductionmentioning

confidence: 99%

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The Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding

Galdikas

Moskaliovienė

2020

Metals

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Plasma nitriding of austenitic stainless steels at moderate temperatures is considered in the presented work. The anisotropic aspects of stress-induced diffusion and influence of nitrogen traps are investigated by kinetic modeling based on rate equations. The model involves diffusion of nitrogen in the presence of internal stress gradients induced by penetrating nitrogen as the next driving force of diffusion after the concentration gradient. The diffusion equation takes into account the fact that nitrogen atoms reside in interstitial sites and in trapping sites. Stress-induced diffusion has an anisotropic nature and depends on the crystalline orientation while trapping–detrapping is isotropic. The simulations are done considering the synergetic effects of both mechanisms and analyzing the properties of both processes separately. Theoretical curves are compared with experimental results taken from the literature. Good agreement between simulated and experimental results is observed, and gives the possibility to find real values of parameters needed for calculations. The nitrogen depth profile shapes, the dependences of nitrogen penetration on nitriding time and on diffusivity, are analyzed considering crystalline orientation of steel single crystal.

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Section: Mass Transport Model-the Coupling Between Nitrogen Stress-assisted Diffusion and Trappingmentioning

confidence: 99%

Section: Mass Transport Model-the Coupling Between Nitrogen Stress-assisted Diffusion and Trappingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding

Galdikas

Moskaliovienė

2020

Metals

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Past, Present and Future Development in Mathematical Modeling for Low Temperature Thermochemical Treatments of Stainless Steels for Enhanced Surface Properties

Fanya

Haruman

2021

J. Phys.: Conf. Ser.

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Research development on mathematical modeling for thermochemical treatment especially in low temperature started from the empirical-based research which focused on conducting many experimental studies to gather metallurgical data. Several thermochemical treatments have been developed experimentally using various process parameters such as temperature, treatment time and gas compositions to understand the effect of certain factors towards the resultant layer. The availability of these experimental data was a crucial factor to obtain precise simulation of the diffusion process by thermochemical treatments in the stainless steels which can reduce the trials and errors of the experimental woks. However, the lack of the metallurgical data remains an obstacle to correlate the empirical and simulation-based research. The recent additive manufacturing research area is also an attractive challenge to generate a mathematical-based simulation of thermochemical treatments of additive manufactured specimen. In this paper, a historical review in connection with modeling development in low temperature thermochemical treatments is presented including the suggested future works to attain commercial software availability in progressive industrial development.

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Coupled Modeling of Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding and Thermal Annealing

2023

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In this paper, nitrogen diffusion is investigated in single-crystalline austenitic stainless steel during modified layer formation and thermal annealing. A generalized system of diffusion equations is derived within a thermodynamic framework from Fick’s laws, which describe nitrogen flux under multiple driving forces, including a concentration gradient and the gradient of hydrostatic stress. Trapping and detrapping phenomena are considered within this model, and nitrogen flux is distinguished depending on whether nitrogen is in a lattice or a trapping site. Furthermore, the effects of anisotropic elasticity in single-crystal austenitic stainless steel on the stress field are investigated. The proposed model is used to simulate the nitrogen transportation process in single-crystalline AISI 316L during ion beam nitriding and after isothermal annealing at three different crystalline orientations. The results of our theoretical predictions are compared with experimental results taken from the literature. It is shown that during isothermal annealing, nitrogen diffusion becomes significantly slower than during nitriding. The diffusion coefficient during the annealing process, compared with the nitriding process, decreases by factors of 4.3, 3.3, and 2.5 for the orientations (001), (011), and (111), respectively.

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Crystallographic Orientation Dependence of Nitrogen Mass Transport in Austenitic Stainless Steel

Cited by 5 publications

References 41 publications

The Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding

The Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding

Past, Present and Future Development in Mathematical Modeling for Low Temperature Thermochemical Treatments of Stainless Steels for Enhanced Surface Properties

Coupled Modeling of Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding and Thermal Annealing

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