Residual stresses and final deformation of an alumina coating: Modeling and measurement

Abstract A simplified ID model has been developed to calculate the temperature time history of alumina layering splats. The splats were obtained by plasma spraying alumina fused and crushed particles (- 45 + 22 µm). The model has shown that for more than 160-200 µm layered splats the solidification time is over 7-10 µs, When spraying thin passes (ep < 15 µm) each splat cools down to substrate preheating temperature before next splat impacts. On the contrary for thick passes (ep = 60 or 180 µm), after depositing a certain thickness (between 160 and 200 µm) depending on spraying conditions, the temperature of the splats never drops below 800-900 K (mean splat temperature). In this case nucleation occurs after flattening is completed. Such conditions allow a columnar growth through the layered splats of each pass and successive passes. The study of the corresponding stresses (quenching σq and expansion mismatch) generated when spraying alumina on XC38 sheet was measured by following continuously the bending of a beam. The comparison of the measurements with the results of a ID model developed by Tsui and Clyne has allowed to calculate the coating Young's modulus Ed and the residual stresses difference at the interface. For thin coatings σq and Ed increase with preheating temperature. For thick coatings the values of Ed and σq are lower than the highest ones of thin coatings. This is probably due to stress relaxation by cracks propagation, the quenching and expansion mismatch stresses increasing with the increasing mean splat temperature.

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Effects of Residual Stresses on Strength and Crack Resistance in ZrO2 with Alumina Coating

Journal of Inorganic Materials ◽

10.15541/jim20210412 ◽

2021 ◽

pp. 412

Author(s):

LI Haiyan ◽

HAO Hongjian ◽

TIAN Yuan ◽

WANG Changan ◽

BAO Yiwang ◽

...

Keyword(s):

Residual Stresses ◽

Crack Resistance ◽

Alumina Coating

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Correlation between pre- and post-treatments of additively manufactured 316L parts and the resulting low cycle fatigue behavior

Rapid Prototyping Journal ◽

10.1108/rpj-01-2021-0017 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Kai-Uwe Garthe ◽

Kay-Peter Hoyer ◽

Leif Hagen ◽

Wolfgang Tillmann ◽

Mirko Schaper

Keyword(s):

Surface Roughness ◽

Residual Stresses ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Atmospheric Plasma ◽

Alumina Coating ◽

Cycle Fatigue ◽

Near Surface ◽

Content Type ◽

Surface Residual Stresses

Purpose The currently existing restrictions regarding the deployment of additively manufactured components because of poor surface roughness, porosity and residual stresses as well as their influence on the low-cycle fatigue (LCF) strength are addressed in this paper. Design/methodology/approach This study aims to evaluating the effect of different pre- and post-treatments on the LCF strength of additively manufactured 316L parts. Therefore, 316L specimens manufactured by laser powder bed fusion were examined in their as-built state as well as after grinding, or coating with regard to the surface roughness, residual stresses and LCF strength. To differentiate between topographical effects and residual stress-related phenomena, stress-relieved 316L specimens served as a reference throughout the investigations. To enable an alumina coating of the 316L components, atmospheric plasma spraying was used, and the near-surface residual stresses and the surface roughness are measured and investigated. Findings The results have shown that the applied pre- and post-treatments such as stress-relief heat treatment, grinding and alumina coating have each led to an increase in LCF strength of the 316L specimens. In contrast, the non-heat-treated specimens predominantly exhibited coating delamination. Originality/value To the best of the authors’ knowledge, this is the first study of the correlation between the LCF behavior of additively manufactured uncoated 316L specimens in comparison with additively manufactured 316L specimens with an alumina coating.

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Stress Evaluation by Neutron and Synchrotron Radiation

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.188.262 ◽

2012 ◽

Vol 188 ◽

pp. 262-267

Author(s):

Alain Lodini ◽

Abdelilah Benmarouane

Keyword(s):

Residual Stresses ◽

Cobalt Alloys ◽

X Ray Diffraction ◽

Element Analysis ◽

Stress Evaluation ◽

X Ray ◽

Steel Forging ◽

Final Deformation ◽

Imaging Instrument

In this paper we present two studies in order to evaluate the residual stresses in two materials. The first one, the residual stresses regenerated in shot peened aluminium plate by neutron diffraction on the strain imaging instrument SALSA at the Institut Laue Langevin, Grenoble, France, also the validation of a model of finite element analysis permitting to predict the final deformation. The second example of this work we use the cobalt-alloys coating deposited on stainless steel forging tools via Plasma Transfer Arc (PTA) process, the evaluation of the residual stresses and characterization of phases close to substrate/coating interface were done by Synchrotron X-ray diffraction.

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Method to evaluate residual stresses in the laser cutting process

Lasers in Engineering ◽

10.1080/08981500290022752 ◽

2002 ◽

Vol 12 (1) ◽

pp. 27-41 ◽

Cited By ~ 7

Author(s):

Y. Zamachtchikov ◽

F. Breaban ◽

P. Vantomme ◽

A. Deffontaine

Keyword(s):

Residual Stresses ◽

Laser Cutting ◽

Cutting Process

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Prediction of residual stresses and springback after bending of a textured aluminium plate

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:20030185 ◽

2003 ◽

Vol 105 ◽

pp. 175-182 ◽

Cited By ~ 2

Author(s):

L. Delannay ◽

R. E. Logé ◽

Y. Chastel ◽

P. Van Houtte

Keyword(s):

Residual Stresses

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Theoretical study of the prestressing strand's stress by computer modeling methods

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-111-1139-1148 ◽

2020 ◽

Vol 76 (11) ◽

pp. 1139-1148

Author(s):

A. G. Korchunov ◽

E. M. Medvedeva ◽

E. M. Golubchik

Keyword(s):

Residual Stresses ◽

High Strength ◽

Pearlitic Steel ◽

Internal Stresses ◽

Steel Microstructure ◽

Compressive Stresses ◽

Wide Range ◽

Prestressing Strands ◽

Increasing Temperature ◽

Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

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