Influence of bonding probabilities in cold spray deposition of composite blends on attained phase contents

Cold gas spraying of metal alloys using single feedstock powder is well explored in terms of impact conditions and critical velocities for bonding of similar particles. In contrast, the mechanism of layer build-up in cold spraying of dissimilar powder blends, especially where the particles have significantly different thermomechanical properties, still misses a systematic description. This study investigates this question by taking W-Cu and Mo-Cu as example blends of significantly dissimilar materials, with potential applications in thermal management systems. By systematically varying feedstock compositions, attained composite deposits are characterized with respect to microstructures, phase contents as well as interface related electrical and mechanical characteristics. The experimental data are further interpreted in view of a statistical model for deposition, considering the different deformation behavior as well as the possibly even repulsive chemical interaction of the dissimilar particles. In this way, the model supplies a quantitative description of the observed deposition efficiency as a function of powder size and composition. In addition, an outline of transferring the applied scope and findings to other cold-sprayed composites or single alloy systems is given. With that, the applied model could support further tuning for cold spraying of powder blends for defined composite production.