Quantitative and Qualitative Nondestructive Evaluation of Cold Spray Manufactured Copper and Aluminum Samples

Abstract

Abstract Cold spray (CS) is a solid-state process for depositing metal powder, accelerated by a high-velocity gas such that it bonds to the substrate metal through kinetic impact energy. Although the technology is finding applications in non-load bearing repair and coating applications, work is needed in the quality control procedures for CS for its use in load bearing structural applications. in this study, the viability of electrical conductivity and through thickness ultrasound wave velocity measurement methods are studied to serve as a means for nondestructive quantitative measurement methods for quality control in CS and potentially other additive manufacturing (AM) methods. Eddy current, ultrasound, porosity, hardness, and uniaxial tensile strength tests were conducted on copper and aluminum samples that were manufactured using CS. Ultrasound measurements of longitudinal wave velocity and eddy current electrical conductivity measurements showed good correlation with process conditions that were varied to control particle velocity to intentionally produce samples with varying deposition quality. Influence of process conditions on particle velocity was confirmed via particle image velocimetry. Porosity, hardness, and tensile test results were further correlated to ultrasound wave velocity and electrical conductivity measurements. The results of this work show that nondestructive testing methods can be effectively used to quantitatively assess the cold spray products for quality control purposes.