Analysis of the residual stress and bonding mechanism in the cold spray technique using experimental and numerical methods

Cold spray is a material deposition technique in which powdered metals are deposited onto metallic and glass substrates as a means of improving functionality, repair or protection of the underlying substrate. The residual stress that builds up in the material during spraying is closely linked to the coating’s integrity and the bonding mechanism. Neutron diffraction residual stresses measurements were carried out at the OPAL research reactor, ANSTO, using the KOWARI strain scanner to investigate an Al-6061 sample with a fine through-thickness resolution of 0.5 mm. The experimentally determined through thickness stress profiles of the macroscopically thick coatings were used to validate FE calculations made for 100 μm thick coatings using the Smooth Particle Hydrodynamics, SPH, techniques. A pronounced plastic strain gradient was apparent in the tested and modelled samples indicative of the significant residual macro-stresses which develop in the cladding/substrate during the deposition. Around the deposited particle’s periphery (in the jetting region) the temperatures are significant, this lends itself to the presence of grain refinement at the periphery of sprayed particles and the propagation of dynamic recrystallization which is closely coupled with the thermal softening of the particle.

Download Full-text

Analysis of the Effect of Casting Residual Stress on Durability by a Combination of Different Numerical Methods

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2011.49.6.468 ◽

2016 ◽

Vol 49 (6) ◽

Keyword(s):

Residual Stress ◽

Numerical Methods

Download Full-text

Microstructure, microhardness and tribological behavior of Al2O3 reinforced A380 aluminum alloy composite coatings prepared by cold spray technique

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2018.07.039 ◽

2018 ◽

Vol 350 ◽

pp. 391-400 ◽

Cited By ~ 18

Author(s):

Xiang Qiu ◽

Naeem ul Haq Tariq ◽

Ji-qiang Wang ◽

Jun-rong Tang ◽

Lawrence Gyansah ◽

...

Keyword(s):

Aluminum Alloy ◽

Cold Spray ◽

Tribological Behavior ◽

Composite Coatings ◽

Alloy Composite ◽

Spray Technique

Download Full-text

Adhesion mechanism of Sn coatings on the carbon fiber reinforced plastics using cold spray technique

Applied Surface Science ◽

10.1016/j.apsusc.2021.151873 ◽

2021 ◽

pp. 151873

Author(s):

Jiayu Sun ◽

Kenta Yamanaka ◽

Shaoyun Zhou ◽

Hiroki Saito ◽

Yuji Ichikawa ◽

...

Keyword(s):

Carbon Fiber ◽

Cold Spray ◽

Fiber Reinforced ◽

Adhesion Mechanism ◽

Carbon Fiber Reinforced Plastics ◽

Reinforced Plastics ◽

Spray Technique ◽

Fiber Reinforced Plastics ◽

Carbon Fiber Reinforced

Download Full-text

Numerical Methods to Predict Distortion in Welded Components

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2008-61497 ◽

2008 ◽

Author(s):

N. A. Leggatt ◽

R. J. Dennis ◽

P. J. Bouchard ◽

M. C. Smith

Keyword(s):

Residual Stress ◽

Numerical Methods ◽

Structural Integrity ◽

Large Strain ◽

Stress Fields ◽

Specimen Thickness ◽

Single Bead ◽

Stress Profiles ◽

Welding Processes ◽

Integrity Assessments

Numerical methods have been established to simulate welding processes. Of particular interest is the ability to predict residual stress fields. These fields are often used in support of structural integrity assessments where they have the potential, when accurately characterised, to offer significantly less conservative predictions of residual profiles compared to those found in assessment codes such as API 579, BS7910 and R6. However, accurate predictions of residual stress profiles that compare favourably with measurements do not necessarily suggest an accurate prediction of component distortions. This paper presents a series of results that compare predicted distortions for a variety of specimen mock-ups with measurements. A range of specimen thicknesses will be studied including, a 4mm thick DH-36 ferritic plate containing a single bead, a 4mm thick DH-36 ferritic plate containing fillet welds, a 25mm thick 316L austenitic plate containing a groove weld and a 35mm thick esshete 1250 austenitic disc containing a concentric ring weld. For each component, distortion measurements have been compared with the predicted distortions with a number of key features being investigated. These include the influence of ‘small’ vs ‘large’ strain deformation theory, the ability to predict distortions using simplified analysis methods such as simultaneous bead deposition and the influence of specimen thickness on the requirement for particular analysis features. The work provides an extremely useful insight into how existing numerical methods used to predict residual stress fields can be utilised to predict the distortions that occur as a result of the welding fabrication process.

Download Full-text

Response of Cold Sprayed Ti6Al4V Coatings to Solid Particle Erosion and Micro-Scratch Wear Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.1680 ◽

2018 ◽

Vol 941 ◽

pp. 1680-1685 ◽

Cited By ~ 3

Author(s):

Miguel Ángel Garrido ◽

Paloma Sirvent ◽

Daniel Elvira ◽

Álvaro Rico ◽

Claudio J. Múnez ◽

...

Keyword(s):

Mechanical Properties ◽

Residual Stresses ◽

Solid Particle ◽

Cold Spray ◽

Mechanical Response ◽

Operating Time ◽

Wear Behaviour ◽

Solid Particle Erosion ◽

Particle Erosion ◽

Spray Technique

Ti6Al4V alloy is widely used for aeronautical components due to a special combination of high mechanical properties, low density and good corrosion resistance at high temperature. These components are usually damaged by particles impacts during their operating time. When the reliability of these components is compromised, they are replaced with the consequent cost of material and time. Spraying coatings on the damaged surface could reveal as an alternative process to repair these components, increasing their operating life. Traditionally, thermal spray processes are used to repair the aeronautical components. However, the coatings produced by these processes are characterized by high residual stresses, porosity and oxidation. The cold spray technique is revealed as a promising spraying alternative due to the characteristic low temperature of the process. Consequently, residual stresses, oxidation, crack formation, phase transformations and microstructural changes are minimized. In this work, a cold spray technique was used to generate Ti6Al4V coatings onto a bulk of the same material. Three different spraying conditions were studied: Ti6Al4V coatings sprayed at 800oC; Ti6Al4V coatings sprayed at 1100oC; and Ti6Al4V coatings sprayed at 1100oC with a subsequent heat treatment: The wear resistance of these coatings was investigated by solid particle erosion and micro-scratch tests. The wear behaviour was determined under several wear tests conditions. Additionally, instrumented indentation tests were carried out on the coatings to determine their mechanical response. The wear mechanisms of the coatings were identified and compared to their microstructure and mechanical properties.

Download Full-text

Theoretical prediction of residual stresses induced by cold spray with experimental validation

Multidiscipline Modeling in Materials and Structures ◽

10.1108/mmms-08-2018-0150 ◽

2019 ◽

Vol 15 (3) ◽

pp. 599-616 ◽

Cited By ~ 4

Author(s):

Dibakor Boruah ◽

Xiang Zhang ◽

Matthew Doré

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Residual Stresses ◽

Cold Spray ◽

Residual Stress Distribution ◽

Thermal Mismatch ◽

Individual Layer ◽

Content Type ◽

Layer Height ◽

Proposed Model

PurposeThe purpose of this paper is to develop a simple analytical model for predicting the through-thickness distribution of residual stresses in a cold spray (CS) deposit-substrate assembly.Design/methodology/approachLayer-by-layer build-up of residual stresses induced by both the peening dominant and thermal mismatch dominant CS processes, taking into account the force and moment equilibrium requirements. The proposed model has been validated with the neutron diffraction measurements, taken from the published literature for different combinations of deposit-substrate assemblies comprising Cu, Mg, Ti, Al and Al alloys.FindingsThrough a parametric study, the influence of geometrical variables (number of layers, substrate height and individual layer height) on the through-thickness residual stress distribution and magnitude are elucidated. Both the number of deposited layers and substrate height affect residual stress magnitude, whereas the individual layer height has little effect. A good agreement has been achieved between the experimentally measured stress distributions and predictions by the proposed model.Originality/valueThe proposed model provides a more thorough explanation of residual stress development mechanisms by the CS process along with mathematical representation. Comparing to existing analytical and finite element methods, it provides a quicker estimation of the residual stress distribution and magnitude. This paper provides comparisons and contrast of the two different residual stress mechanisms: the peening dominant and the thermal mismatch dominant. The proposed model allows parametric studies of geometric variables, and can potentially contribute to CS process optimisation aiming at residual stress control.

Download Full-text