Evaluation of Residual Stresses in PVD Coatings by Means of Strip Substrate Length Variation and Curvature Method of Plate Substrate

The aim of the study was to determine macroscopic residual stresses in Physical Vapor Deposits (PVD) coatings through measurement of the length variation of the strip substrates coated on both sides. The length change of the strip was reduced to the deflection of the middle cross-section of the elastic element and was recorded by four strain gauges. For validating the obtained results, the conventional curvature method was used. As an application, residual stresses in hard AlCrN PVD coatings were investigated. The coatings were nanolayered to achieve better coating toughness for blanking and punching applications. The steel strips and steel plates with two thicknesses were used as the substrate. The values of the compressive residual stresses, determined by both methods for the investigated coatings, were very high (3.3 -3.6 GPa) independent of coating thickness and practically equal within the measurement uncertainty of the method. Good agreement between the experimental results obtained with both methods suggests that the presented method, strip length variation, is applicable for determination of residual stresses in coatings. Compressive stresses in coatings are desirable as they strengthen the coating.

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Average Residual Stresses in Hard Physical Vapor Deposited (PVD) Coatings

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.799.20 ◽

2019 ◽

Vol 799 ◽

pp. 20-25

Author(s):

Harri Lille ◽

Alexander Ryabchikov ◽

Jakub Kõo ◽

Valdek Mikli ◽

Eron Adoberg ◽

...

Keyword(s):

Residual Stresses ◽

Front Surface ◽

Back Surface ◽

Length Variation ◽

Pvd Coatings ◽

Cross Sectional ◽

Average Residual ◽

Thin Walled ◽

Compressive Residual Stresses ◽

Very High

In this study we determined average residual stresses in hard nitride PVD AlCrN, TiAlN and TiCN coatings through simultaneous measurement of length variation in thin-walled tubular substrates and of the curvature of plate substrates. A device for measurement of the length of the tube was developed. Inside the depositing chamber the tube and the plate were fixed parallel in the relation to the axis of the rotating cathode. One batch of plate samples was produced by deposition on front surface (facing the cathode) and the other batch, by deposition on back surface (with back to the cathode). The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM). The thicknesses of the coatings deposited on front and back surfaces of the plates and on the tube were significantly different. The values of average compressive residual stresses, determined by both methods, were very high irrespective of coating thickness. It was found that the values of compressive residual stresses in the coating were dependent on the shape of the substrate and on its position in the relation to the axis of the rotating cathode.

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Evaluation of Residual Stresses in PVD Coatings by means of Tubular Substrate Length Variation

Residual Stresses 2018 ◽

10.21741/9781945291890-21 ◽

2018 ◽

Cited By ~ 2

Keyword(s):

Residual Stresses ◽

Length Variation ◽

Pvd Coatings

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Evaluation of Residual Stresses in PVD Coatings by Means of the Curvature Method of Plate

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.721.404 ◽

2016 ◽

Vol 721 ◽

pp. 404-408 ◽

Cited By ~ 1

Author(s):

Harri Lille ◽

Alexander Ryabchikov ◽

Eron Adoberg ◽

Liisa Kurissoo ◽

Priidu Peetsalu ◽

...

Keyword(s):

Residual Stresses ◽

Physical Vapor Deposition ◽

Metal Cutting ◽

Cutting Tools ◽

Layer Growth ◽

Hard Coatings ◽

Steel Plates ◽

Nickel Steel ◽

Pvd Coatings ◽

Mechanical And Tribological Properties

Physical Vapor Deposition (PVD) coatings are primarily designed for metal cutting tools operating in extreme machining and blanking conditions. Residual stresses arising during coating deposition exert an important effect on the service life of the coating through influencing mechanical and tribological properties and adhesion. To determine macroscopic residual stresses, the conventional curvature method was used. As an application, residual stresses in four aluminum based PVD hard coatings, i.e. AlTiN, AlTiSiN, AlCrN, and AlCrSiN, were investigated in the presence of the Ti adhesion layer. Nickel steel plates and steel plates were used as the substrate. Residual stresses were compressive and high (3.0-7.5 GPa) in all coatings. Compressive stresses in coatings are desirable in cohesive tool damage as they strengthen the coating. The values of residual stresses were not significantly dependent on the angle of plate placement (parallel (0°), inclined (45°) and perpendicular (90°)) in relation to the PVD cathode in the deposition chamber. The magnitude of residual stresses is influenced by intrinsic strain at layer growth rather than by thermal stress.

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Residual Stresses on Various PVD Hard Coatings on Tube and Plate Substrates

Coatings ◽

10.3390/coatings10111054 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1054

Author(s):

Harri Lille ◽

Alexander Ryabchikov ◽

Priidu Peetsalu ◽

Liina Lind ◽

Fjodor Sergejev ◽

...

Keyword(s):

Residual Stresses ◽

Rear Surface ◽

Front Surface ◽

Length Change ◽

Hard Coatings ◽

Wear Testing ◽

Tube Length ◽

Length Variation ◽

Cross Sectional ◽

Compressive Residual Stresses

In this study, the average residual stresses were determined in hard PVD nACRo (nc-AlCrN/a-Si3N4), nACo (nc-AlTiN/a-Si3N4), AlCrN, TiAlN, and TiCN commercial coatings through the deflection of the plate substrates and the simultaneous measurement of length variation in thin-walled tubular substrates. The length measuring unit was used for the measurement of any length change in the tubular substrate. A change in tube length was reduced to the deflection of the middle cross-section of the elastic element for which deformation was measured using four strain gauges. The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM), and a determination was made of the chemical composition of the coatings and substrate by means of energy dispersive X-ray spectroscopy (EDS). The values of average compressive residual stresses, as determined by both methods, were very high (with a variation of between 2.05 and 6.63 GPa), irrespective of coating thickness, but were dependent upon the shape of the substrate and on its position in relation to the axis of the rotating cathode. The thicknesses of the coatings that were deposited on the plates with two parallel fixings (such as the nACRo coatings on the front surface at 6.8 μm and on the rear surface at 2.9 μm) and on the tubular substrates (10.0 μm) were significantly different. The higher average compressive residual stresses in the coating correlate to the higher average relative wear resistance that was obtained during field wear testing.

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Determination of residual macrostresses in surface layer of solid-rolled railway wheels disks by X-ray diffractometry

Blanking productions in mechanical engineering (press forging, foundry and other productions) ◽

10.36652/1684-1107-2020-18-12-567-571 ◽

2020 ◽

pp. 567-571

Author(s):

I.G. Roberov ◽

D.B. Matveev ◽

A.Yu. Bespamyatnykh ◽

V.S. Grama ◽

M.A. Kiselev ◽

...

Keyword(s):

Surface Layer ◽

Stress State ◽

Residual Stresses ◽

Rolled Steel ◽

X Ray ◽

Compressive Stresses ◽

Surface Residual Stresses ◽

Residual Macrostresses ◽

Railway Wheels

Residual stresses on the surface of disks of one-piece-rolled steel railway wheels, caused by their fi nishing (turning) with different tool feed rate and speed, are measured using the X-ray diffractometric method implemented using the DRP portable diffractometer. It is shown that the specifi ed fi nishing parameters have signifi cant infl uence on the level of surface residual stresses induced by fi nishing. The most favorable stress state (compressive stresses up to –200 MPa) on the surface of the disks is achieved under relatively small values of tool feed and speed. The results may serve as basis for improving of the fi nishing technology of solid-rolled wheels.

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Bestimmung von Eigenspannungen in ebenen plattierten Werkstoffen. Teil II: Eigenspannungen in warmgewalzten und sprenggeschweißten austenitplattierten Stahlblechen / Determination of residual stresses in flat plated materials. Part II: Residual stresses in hot rolled clad and explosive bonded austenitic steel to steel plates / Determination des contraintes rösiduelles dans des materiaux lamines parallälement. Partie II: Contraintes rösiduelles dans des plaques d’acier austöenitique laminöes ä chaud et soud&es par explosion

Materials Testing ◽

10.1515/mt-1972-141103 ◽

1972 ◽

Vol 14 (11) ◽

pp. 380-387

Author(s):

Heinz Schimmöller

Keyword(s):

Residual Stresses ◽

Austenitic Steel ◽

Steel Plates ◽

Hot Rolled

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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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