Effects of process variants on residual stresses in wire arc additive manufacturing of aluminium alloy 5183

Abstract Development of residual stress of high magnitude, to the extent of material yield strength and in some cases higher than yield strength, is one of the major challenges faced by components produced using wire arc additive manufacturing (WAAM). This study focuses on aluminium alloy 5183 with respect to the residual stress formation and distribution in WAAM builds. Residual stresses were determined using the contour method. The effects of processing conditions, such as substrate thickness, interlayer temperature and deposit height on the magnitude and distribution of residual stresses were investigated. Substrate thickness was found to have a major influence on the residual stress distribution along the sample height. Tensile residual stress up to the value of the material yield strength was present. Majority part of deposit showed tensile stress while substrate showed compensating compressive residual stress. Lower interlayer temperature samples exhibited residual stresses of higher degree of magnitude compared sample produced using higher interlayer temperature. Deposit height i.e. total number of layers affected stress distribution pattern similar to substrate thickness.

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Residual Stress and Microstructure of a Ti-6Al-4V Wire Arc Additive Manufacturing Hybrid Demonstrator

Metals ◽

10.3390/met10060701 ◽

2020 ◽

Vol 10 (6) ◽

pp. 701

Author(s):

Tatiana Mishurova ◽

Benjamin Sydow ◽

Tobias Thiede ◽

Irina Sizova ◽

Alexander Ulbricht ◽

...

Keyword(s):

Residual Stress ◽

Additive Manufacturing ◽

Residual Stresses ◽

Structural Integrity ◽

Hybrid Approach ◽

Aerospace Applications ◽

Machined Parts ◽

Functional Features ◽

Tool Set ◽

Wire Arc Additive Manufacturing

Wire Arc Additive Manufacturing (WAAM) features high deposition rates and, thus, allows production of large components that are relevant for aerospace applications. However, a lot of aerospace parts are currently produced by forging or machining alone to ensure fast production and to obtain good mechanical properties; the use of these conventional process routes causes high tooling and material costs. A hybrid approach (a combination of forging and WAAM) allows making production more efficient. In this fashion, further structural or functional features can be built in any direction without using additional tools for every part. By using a combination of forging basic geometries with one tool set and adding the functional features by means of WAAM, the tool costs and material waste can be reduced compared to either completely forged or machined parts. One of the factors influencing the structural integrity of additively manufactured parts are (high) residual stresses, generated during the build process. In this study, the triaxial residual stress profiles in a hybrid WAAM part are reported, as determined by neutron diffraction. The analysis is complemented by microstructural investigations, showing a gradient of microstructure (shape and size of grains) along the part height. The highest residual stresses were found in the transition zone (between WAAM and forged part). The total stress range showed to be lower than expected for WAAM components. This could be explained by the thermal history of the component.

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Residual Stress Relief in the Aluminium Alloy 7075

Materials Science Forum ◽

10.4028/www.scientific.net/msf.905.31 ◽

2017 ◽

Vol 905 ◽

pp. 31-39 ◽

Cited By ~ 1

Author(s):

Jeremy S. Robinson ◽

Christopher E. Truman ◽

Thilo Pirling ◽

Tobias Panzner

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Neutron Diffraction ◽

Residual Stresses ◽

Aluminium Alloy ◽

Stress Relief ◽

Residual Stress Distribution ◽

Cold Compression ◽

Heat Treated ◽

Minimum Residual

The residual stresses in heat treated 7075 aluminium alloy blocks have been characterised using two neutron diffraction strain scanning instruments. The influence of uniaxial cold compression (1-10%) on relieving the residual stress has been determined. Increasing the magnitude of cold compression from 1 to 10% has been shown to have a beneficial effect on the residual stress distribution by reducing the range between the maximum and minimum residual stresses. The effect of over aging 7075 on residual stress has also been characterised using neutron diffraction and this was found to reduce the residual stress by 25-40%. A relationship between {311} peaks widths and amount of cold compression was also observed.

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Experimental and Numerical Analysis of the Distribution of Residual Stresses Induced by Laser Shock Peening in a 2050-T8 Aluminium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.681.296 ◽

2011 ◽

Vol 681 ◽

pp. 296-302 ◽

Cited By ~ 3

Author(s):

Neila Hfaiedh ◽

P. Peyre ◽

I. Popa ◽

Vincent Vignal ◽

Wilfrid Seiler ◽

...

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Residual Stresses ◽

Aluminium Alloy ◽

Residual Stress Distribution ◽

Laser Shock Peening ◽

Treatment Technique ◽

Laser Shock ◽

X Ray Diffraction ◽

Shock Peening

Laser shock peening (LSP) is an innovative surface treatment technique successfully applied to improving fatigue performance of metallic material. The specific characteristic of (LSP) is the generation of a low work-hardening and a deep compressive residual stresses mechanically produced by a laser-induced shock wave propagating in the material. The aim of this study is to analyse the residual stress distribution induced by laser peening in 2050-T8 aluminium alloy experimentally by the X-ray diffraction technique (method sin2Y) and numerically, by a finite element numerical modelling. A specific focus was put on the residual stress distribution along the surface of the impacted material.

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Abrasive Waterjet Peening With Elastic Prestress: Subsurface Residual Stress Distribution

Volume 3: Design and Manufacturing ◽

10.1115/imece2007-43473 ◽

2007 ◽

Cited By ~ 1

Author(s):

Balaji Sadasivam ◽

Alpay Hizal ◽

Dwayne Arola

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Stress Field ◽

Yield Strength ◽

Residual Stresses ◽

Residual Stress Distribution ◽

Abrasive Waterjet ◽

Residual Stress Field ◽

Surface Residual Stress ◽

Compressive Residual Stresses

Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.

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Effect of Cryogenic Treatment on Internal Residual Stresses of Hydrogen-Resistant Steel

Micromachines ◽

10.3390/mi12101179 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1179

Author(s):

Fengxiang Shang ◽

Jinxing Kong ◽

Dongxing Du ◽

Zheng Zhang ◽

Yunhua Li

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Residual Stresses ◽

Electron Backscatter Diffraction ◽

Cryogenic Treatment ◽

Temperature Treatment ◽

Residual Stress Distribution ◽

Contour Method ◽

High Temperature Treatment ◽

Resistant Steel

To reduce the influence of internal residual stress on the processing deformation of thin-walled hydrogen-resistant steel components, combined aging cryogenic and high-temperature treatment was used to eliminate the residual stress, and the effect of cryogenic process parameters on the initial residual stress of the specimens was compared and analyzed based on the contour method. X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy were used to research the mechanism of the effect of cryogenic treatment on the internal residual stress of the specimen. After forging, the internal residual stress distribution of the hydrogen-resistant steel specimens without aging was characterized by tensile stress on the core and compressive stress on both sides, with a stress amplitude of −350–270 MPa. After compound treatment of -130 °C for 10 h and 350 °C for 2 h, the internal residual stress distribution remained unchanged, and the stresses decreased to −150–100 MPa. The internal residual stresses were reduced by 57%–63% compared with the untreated specimens. The cryogenic treatment did not cause phase transformation and carbide precipitation of the hydrogen-resistant steel material. Instead, grain refinement and dislocation density depletion were the main reasons for the reduction in internal residual stresses in the specimens.

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A numerical prediction of residual stress for a thin-walled part with geometrical features fabricated by GMA-based additive manufacturing

Rapid Prototyping Journal ◽

10.1108/rpj-08-2018-0193 ◽

2019 ◽

Vol 26 (2) ◽

pp. 299-308

Author(s):

Rong Li ◽

Jun Xiong

Keyword(s):

Residual Stress ◽

Additive Manufacturing ◽

Stress Distribution ◽

Residual Stresses ◽

Residual Stress Distribution ◽

Stress Distributions ◽

Content Type ◽

Geometrical Features ◽

Longitudinal Residual Stress ◽

Thin Walled

Purpose An accurate prediction of process-induced residual stress is necessary to prevent large distortion and cracks in gas metal arc (GMA)-based additive manufactured parts, especially thin-walled parts. The purpose of this study is to present an investigation into predicting the residual stress distributions of a thin-walled component with geometrical features. Design/methodology/approach A coupled thermo-mechanical finite element model considering a general Goldak double ellipsoidal heat source is built for a thin-walled component with geometrical features. To confirm the accuracy of the model, corresponding experiments are performed using a positional deposition method in which the torch is tilted from the normal direction of the substrate. During the experiment, the thermal cycle curves of locations on the substrate are obtained by thermocouples. The residual stresses on the substrate and part are measured using X-ray diffraction. The validated model is used to investigate the thermal stress evolution and residual stress distributions of the substrate and part. Findings Decent agreements are achieved after comparing the experimental and simulated results. It is shown that the geometrical feature of the part gives rise to an asymmetrical transversal residual stress distribution on the substrate surface, while it has a minimal influence on the longitudinal residual stress distribution. The residual stress distributions of the part are spatially uneven. The longitudinal tensile residual stress is the prominent residual stress in the central area of the component. Large wall-growth tensile residual stresses, which may cause delamination, appear at both ends of the component and the substrate–component interfaces. Originality/value The predicted residual stress distributions of the thin-walled part with geometrical features are helpful to understand the influence of geometry on the thermo-mechanical behavior in GMA-based additive manufacturing.

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Effect of Phase Transformations on Scanning Strategy in WAAM Fabrication

Materials ◽

10.3390/ma14247871 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7871

Author(s):

Muhammad Hassaan Ali ◽

You Sung Han

Keyword(s):

Residual Stress ◽

Additive Manufacturing ◽

Residual Stresses ◽

Phase Transformations ◽

Manufacturing Industry ◽

Welding Process ◽

Stress Generation ◽

Temperature History ◽

History Of ◽

Wire Arc Additive Manufacturing

Due to its high production rates and low cost as compared to other metal additive manufacturing processes, wire arc additive manufacturing (WAAM) has become an emerging technology in the manufacturing industry. However, the residual stress generation and part distortion hinder its widespread adoption because of the complex thermal build-histories of WAAM parts. One of the ways to alleviate this problem is to consider the effects of scan strategies as it directly influences the thermal history of the built part. Since WAAM itself is an evolved welding process and even though it is evident from welding studies that phase transformations directly affect the residual stresses in welded parts, it remains unclear how the consideration of phase transformations for different scan strategies will affect the residual stresses and distortions in the WAAMed parts. A FEM study has been performed to elucidate the effects of phase transformations on residual stresses and the distortion for different deposition patterns. The current findings highlight that for the fabrication of low-carbon martensitic steels: The consideration of phase transformations for line-type discontinuous patterns (alternate and raster) do not significantly affect the residual stresses. Consideration of phase transformations significantly affects residual stresses for continuous patterns (zigzag, in–out and out–in). To accurately simulate complex patterns, phase transformations should be considered because the patterns directly influence the temperature history of the built part and will thus affect the phase transformations, the residual stresses and the warpage. During the fabrication of WAAM parts, whenever possible, discontinuous line scanning patterns should be considered as they provide the part with uniform residual stress and distortion. The alternate line pattern has been found to be the most consistent overall pattern.

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The Contour Method for Residual Stress Determination Applied to an AA6082-T6 Friction Stir Butt Weld

Materials Science Forum ◽

10.4028/www.scientific.net/msf.681.177 ◽

2011 ◽

Vol 681 ◽

pp. 177-181 ◽

Cited By ~ 7

Author(s):

Valentin Richter-Trummer ◽

Pedro Miguel Guimarães Pires Moreira ◽

João Ribeiro ◽

Paulo Manuel Salgado Tavares de Castro

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Residual Stresses ◽

Cross Section ◽

Residual Stress Distribution ◽

Contour Method ◽

Friction Stir Weld ◽

Hole Drilling ◽

Butt Weld ◽

Friction Stir

Residual stresses parallel to the welding direction on a cross-section of a 3 mm thick friction stir butt-welded aluminum alloy AA6082-T6 plate were determined using the contour method. A full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone. The typical M-shape, usually described for the residual stress distribution in friction stir welds, was found. The maximum residual stresses are below the yield strength of the material in the shoulder region and, outside of the welding region, low tensile and compressive residual stresses are responsible for the necessary stress equilibrium on the plane of interest. A comparison was made with the established incremental hole drilling technique on an equivalent plate for validation and good agreement of both techniques was obtained. The distribution, as well as the magnitude of the residual stresses measured by both techniques, is very similar, thus validating both the experimental and numerical procedures used for the contour method application, presented and discussed in the present paper.

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Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408920964019 ◽

2020 ◽

pp. 095440892096401

Author(s):

Ying Hong ◽

Xuesheng Wang ◽

Yan Wang ◽

Zhao Zhang ◽

Yong Han

Keyword(s):

Residual Stress ◽

Stainless Steel ◽

Yield Strength ◽

Residual Stresses ◽

Heat Exchangers ◽

Nuclear Power ◽

The Finite Element Method ◽

Power Stations ◽

Stainless Steel 304 ◽

Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

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Effects of Roughness on Stresses in an Oxide Scale Formed on a Superalloy Substrate

Coatings ◽

10.3390/coatings11040479 ◽

2021 ◽

Vol 11 (4) ◽

pp. 479

Author(s):

Yang Zhao ◽

Fan Sun ◽

Peng Jiang ◽

Yongle Sun

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Residual Stresses ◽

Oxide Scale ◽

Rough Surface ◽

Alumina Scale ◽

Growth Stress ◽

Oxide Growth ◽

Substrate Thickness ◽

Roughness Effect

The effects of surface roughness on the stresses in an alumina scale formed on a Fecralloy substrate are investigated. Spherical indenters were used to create indents with different radii and depths to represent surface roughness and then the roughness effect was studied comprehensively. It was found that the residual stresses in the alumina scale formed around the rough surface are almost constant and they are dominated by the curvature rather than the depth of the roughness. Oxidation changes the surface roughness. The edge of the indent was sharpened after oxidation and the residual stress there was released presumably due to cracking. The residual stresses in the alumina scale decrease with increase in oxidation time, while the substrate thickness has little effect, given that the substrate is thicker than the alumina scale. Furthermore, the effect of roughness on the oxide growth stress is analysed. This work indicates that the surface roughness should be considered for evaluation of stresses in coatings.

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