An experimental/numerical study of bonding mechanism in cold spray technology for metals
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ORIGINAL ARTICLE
An experimental/numerical study of bonding mechanism in cold spray technology for metals Antonio Viscusi 1
&
Matteo Bruno 1 & Luca Esposito 1 & Gabriel Testa 2
Received: 29 May 2020 / Accepted: 7 September 2020 / Published online: 15 September 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020
Abstract The cold spray technology is a relatively new additive process allowing for the deposition of metallic coatings on metallic substrates; the particles impacting on target surface at high velocity deform and bond together leading to the coating formation and grow-up. Although the impact phenomena have been studied by several scientists in the last decades, the actual bonding mechanism for cold spray particles is still a recent focus of research. Therefore, aiming to further investigate the intriguing phenomena governing the particle-substrate interaction in cold spray, both experimental and numerical studies were carried out in this research activity. Ballistic tests were performed by impacting a single lead particle (1.5 mm in diameter) on a lead substrate at different impact velocities through a light ballistic airgun. A high-frequency camera was used to observe the particle impact and measure impact and rebound velocities. A detailed 3D quarter symmetric numerical model was developed and impact simulations were performed. The comparison between the experimental results and the numerical outcomes in terms of particles and substrate deformations as well as particle rebound velocity allowed for the validation of the model. The validated numerical approach was used to study the thermo-mechanical regimes taking place on impact surface pointing out the rule of strain-temperature interaction in cold spray bonding. On these results, a temperaturebased bonding hypothesis was proposed and an original bonding algorithm was implemented on the numerical model. Keywords Cold spray technology . Additive manufacturing . Particle bonding mechanism . FEM model . Ballistic approach . Bonding algorithm
1 Introduction Cold gas dynamic spray technology, or generally referred to as cold spray (CS), allows for the deposition of coating on both metallic and non-metallic substrates, thanks to the high content of kinetic energy of the processed particles which are dragged by a pressurized gas stream [1]. Unlike other thermal spray processes such as high-velocity oxygen fuel (HVOF), flame wire spraying, flame powder spraying, arc wire spraying and plasma spraying, the relatively low operating temperature of CS permits the deposition of variable thickness coats without arising of
* Antonio Viscusi [email protected] 1
Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
2
Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, 03043 Cassino, Italy
undesired phenomena such as material microstructure alteration, residual stress and embrittlement of both coating and substrate [2]. The c
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