Heterogeneous Distribution of Mechanical Properties of Single-Particle Cold Spray Impacts

AA Hemeda and A Mishra and J Xu and CT Wu and D Cote and M Siopis and IM Nault and VK Champagne and SW Lee and M Aindow and A Nardi and JW Palko and Y Ma, JOURNAL OF THERMAL SPRAY TECHNOLOGY, 31, 498-507 (2022).

DOI: 10.1007/s11666-022-01334-y

In this paper, an axisymmetric smoothed particle hydrodynamic (ASPH) approach is used to study the micromechanical performance of Al6061 single-particle deposition by a cold spray (CS) process. The ASPH model is first validated against several benchmark problems as provided in the manuscript. Then, the ASPH model is applied to simulate the impact of a particle onto a substrate of the same material. Micropillars are then extracted from the final deposition at different positions of the splat to conduct numerical simulations on micro-compression behavior. Micropillar relaxation from residual stresses after extraction is considered in the simulation. The uniaxial compression of different micropillars is simulated to study the change in mechanical properties due to impact. It is found that the yield strength at the particle- substrate interface is two to three times greater than that in the bulk. Also, the results suggested that there are heterogeneous mechanical properties in the splat and along the splat-substrate interface. A theoretical study using the simplified Johnson-Cook model is also carried out to validate the numerical results on the heterogeneous mechanical properties. This model can be applied to more complex geometries including multi-particle depositions and coatings. The present work can thus be used to estimate the alteration in mechanical properties due to the CS process as a guide to experimentalists.

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