Cold spray NDE for porosity and other process anomalies

Glass, S. W.; Larche, Michael R.; Prowant, Matthew S.; Suter, Jonathan D.; Lareau, J. P.; Jiang, Xiangyang; Ross, Kenneth A.

doi:10.1063/1.5031507

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…The high-pressure system is better suited for harder metals and is capable of particle velocities of ∼800−1400 m/s. 39 With any given material system, there are multiple parameters under operator control, including the powder feed rate, spray distance, spray angle, scanning step, nozzle traverse speed, gas pressure, gas temperature, and gas type, 40 allowing for deposition of various track thicknesses and mechanical properties. As shown in Figure 3d for titanium deposition, incomplete mixing, trapped oxides, and porosity are commonly observed in cold spray and can result in inferior as-deposited mechanical properties.…”

Section: The First Candidate: Cold Spraymentioning

confidence: 99%

Solid-State Metal Additive Manufacturing for Structural Repair

et al. 2021

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Metrics & MoreArticle Recommendations CONSPECTUS: Structural metal components play a vital role in a broad range of industries, from aerospace and automotive to infrastructure and defense. In service, these components can experience substantial wear, thermal fatigue, erosion, corrosion, or chemical reactions, resulting in significant surface or even volumetric damages. Replacement of these components is often energy-intensive and economically impractical. Structural repair, which aims to restore the original geometry while enabling good mechanical performance postrepair, can offset the costs dramatically. Depending on the additive capabilities and bonding mechanisms, structural repair technologies can be divided into four categories: nonadditive, nonmelting-based; nonadditive, melting-based; additive, nonmelting-based; additive, melting-based. Although melting-based approaches can be applied to various repair geometries with good precision, the underlying melting and solidification processes inevitably lead to crucial problems impacting the mechanical performance, such as solidification porosity, high residual stresses, dendritic microstructure formation, elemental segregation, hot cracking, and stress corrosion cracking. To fundamentally solve or minimize these problems, one may employ solid-state technologies that leverage ultrasonic vibration, friction stirring, or particle impact to facilitate metallurgical bond formation. For robust geometry restoration, an additive capability needs to be incorporated for continuous material feeding and precise deposition path control. Currently, two solid-state technologies satisfy the requirement, cold spray and additive friction stir deposition.In this Account, we discuss the structural repair enabled by solid-state metal additive manufacturing, focusing on (i) cold spray, which is a relatively established process, and (ii) additive friction stir deposition, which is an emerging process recently triggering significant research effortsthe authors are particularly invested in this process and are pioneering the research on process fundamentals and structural repair applications. In cold spray, a substrate is bombarded with small metal particles at high speed; upon impact, the particles and substrate co-deform, resulting in interfacial bonding and mechanical interlocking. In additive friction stir deposition, frictional heat is created after the rapidly rotating feed-rod contacts the substrate, followed by co-plastic deformation and mixing between the deposited material and substrate surface. This renders a strong interface with complex 3D features. Both cold spray and additive friction stir deposition can be applied to a wide range of repair geometries while preventing hot cracking and high thermal exposure. Although cold spray has better portability and spatial resolution than additive friction stir deposition, we believe that additive friction stir deposition is the top choice for repairing load-bearing components given its unparalleled capabilities of rendering equiaxed...

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Section: The First Candidate: Cold Spraymentioning

confidence: 99%

Solid-State Metal Additive Manufacturing for Structural Repair

et al. 2021

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“…In cold spraying, deposition parameters (e.g., temperature and velocity of the gas, standoff distance, and angle of spraying [ 21 ]) and particle morphology (size, shape, type of particles) significantly affect the porosity level in the final coating [ 28 ]. To date, limited studies have focused on exploring the effect of porosity on the mechanical properties and structural integrity of Al/B

C coatings [ 27 , 29 , 30 , 31 , 32 ]. In the literature, Zhao et al [ 33 ] systematically investigated the effect of B

C and Al feedstock particle size on the weight percentage of the B

C in the cold-sprayed Al/B

C coating, and they found the optimal particle size for Al and B

C was 15

m to maximize the volume fraction of the B

C particles (≈30%), and to achieve maximum deposition efficiency.…”

Section: Introductionmentioning

confidence: 99%

Impact Deposition Behavior of Al/B4C Cold-Sprayed Composite Coatings: Understanding the Role of Porosity on Particle Retention

2023

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This study explores the role of porosity in the impact deposition of a ceramic-reinforced metal-matrix (i.e., Al/B4C) composite coating fabricated via cold spraying. The Johnson–Holmquist–Beissel constitutive law and the modified Gurson–Tvergaard–Needleman model were used to describe the high strain-rate behavior of the boron carbide and the aluminum metal matrix during impact deposition, respectively. Within a finite element model framework, the Arbitrary Lagrangian–Eulerian technique is implemented to explore the roles of reinforcement particle size and velocity, and pore size and depth in particle retention by examining the post-impact crater morphology, penetration depth, and localized plastic deformation of the aluminum substrate. Results reveal that some degree of matrix porosity may improve particle retention. In particular, porosity near the surface facilitates particle retention at lower impact velocities, while kinetic energy dominates particle retention at higher deposition velocities. Altogether, these results provide insights into the effect of deposition variables (i.e., particle size, impact velocity, pore size, and pore depth) on particle retention that improves coating quality.

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