Abstract
Implementation of the cold spray (CS) technology in manufacturing and repair creates a demand for reliable quality control and process monitoring measures. In this regard, particle size and impact velocity are undoubtedly the most important control parameters in CS. Several in-flight measurement systems for particle velocimetry are now available commercially for CS. These systems provide great potential to be used as a diagnostic tool for validating CS system performance in industrial applications. However, post processing the velocimetry data is required in many instances for achieving a complete understanding of the particle flow field. In this study, particle velocimetry is used in conjunction with computational fluid dynamics (CFD) simulations to: (i) identify the physical factors that dictate the particle velocity and its variability; (ii) develop high fidelity CFD models to accurately predict particle flight parameters that cannot be measured by available experimental tools; and (iii) present the capabilities of state-of-the-art velocimeters as a reliable diagnostic tool for measuring the consistency and repeatability of CS systems in manufacturing settings. In-flight particle size, location, and velocity are measured using a commercially available velocimeter for aluminum and copper particles sprayed with supersonic nozzles using helium, nitrogen, and air by two high pressure CS systems. As a result of this work, particle sphericity was clearly identified to have strong effects on particle velocity and to be one of the main factors of the variability of particle velocity. Furthermore, methods for building a high-fidelity 3D-CFD model was presented. CFD models were validated using particle velocimetry and schlieren imaging. Finally, particle velocimetry is shown to be a valid diagnostics tool for CS with systems capable of measuring in-flight particle velocities along with particle sizes. This article also outlines steps necessary for conducting cold spray process diagnostics repeatably and reliably.
Highlights
Cold spray (CS) additive manufacturing is a line-of-sight material deposition process and has primarily been used as a coating and repair technique in automotive [1], aerospace [2,3,4], marine [5,6], and defense applications [7,8,9]
The example given here shows that the use of particle velocimetry systems that are capable of accurately measuring both particle size and velocity (e.g., Oseir HiWatch HR), is a viable method for both designing cold spray procedures and equipment and for daily system operations
Arithmetic and volumetric mean particle size measured by optical microscopy for the Praxair Cu-159-03 powder were 18.5 and 22.4 μm, respectively, whereas the velocimetry measurements yield a mean size of approximately 30 μm, which means smaller particles are harder to realize
Summary
Cold spray (CS) additive manufacturing is a line-of-sight material deposition process and has primarily been used as a coating and repair technique in automotive [1], aerospace [2,3,4], marine [5,6], and defense applications [7,8,9]. CS has an increasing presence in 3D printing of metal and metal matrix composite structures [10,11]. The technology utilizes a converging-diverging supersonic nozzle to spray metals, metal-ceramic blends, cermet, and polymer powders onto target surfaces (substrates) at velocities that reach 1500 m/s [12]. Propulsion of particles is achieved primarily by drag forces in spray nozzles that expand compressible gases such as air, nitrogen, and helium up to Mach 3.5. Layering of particles on top of each other generates thick deposits with a minimum thickness of approximately 50 μm and virtually no maximum thickness
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
