Additive Manufacturing (ARL)

*Funding agency: Army Research Laboratory (ARL) Aberdeen Proving Ground

In cold spray (CS), supersonically sprayed metal microparticles are consolidated, without global melting of the microparticles due to extreme plastic deformation arising from the collison to a substrate. Microparticles’ material characteristics attained from the supersonic collision essentially govern the performance of the final macroscopic object. However, due to highly-nonlinear and non-equilibrium plastic deformation of the microparticles, quantitative understanding of the high-strain-rate (HSR) characteristics of the particles has been limited. Although various technically-matured computation modelings are available, it is challenging to produce reliable outcomes without proper calibration and validation of the models using accurate, repeatable, and systematically obtained experimental reference data. In contrast, when the microparticles are accelerated through a conventional CS system, individual microparticles’ impact velocity, mass, temperature, and shape can only be marginally estimated with various statistical errors. In this aspect, it is crucial to have an experimental platform for reference data generation of HSR single particle dynamics with precisely defined collision parameters such as particle’s impact velocity, mass, temperature, and shape.

Based on our experimental capabilities, we have performed:
(i) Single particle characterization of powders, produced under different conditions, which will provide a rapid feedback to the powder production groups to optimize the production conditions. The optimized processing conditions will be provided to the experimental material database.
(ii) Single particle impact experiment with controlled powders is being performed to provide basic calibration data for numerical modeling groups
(iii) The standard reference data from the single particle impact experiment will be used for a CS experimental material database
(iv) We are providing single particle specimens with accurate impact conditions to other extensive characterization groups for high-resolution compositional, structural, and crystallographic analysis. The outcomes from the extensive characterization groups will provide supplementary calibration to the numerical modeling group.