Evaluation of a laser powder bed fusion designer Al-Mg-Zr-Si alloy for cold spray additive manufacturing

Abstract

Metal additive manufacturing (AM) is a constantly developing approach utilized in many novel applications. Most metal AM techniques utilize alloys designed for traditional processing conditions, such as casting, whereas implementing alloys designed for AM may prove useful. Given the proven utility of the Al-Mg-Zr-Si Addalloy 5T® in melt-driven AM, this study investigated the use of this alloy in cold spray (CS), as minimal research has explored alloy design for use in solid-state processing. The as-atomized powder and CS samples were evaluated microstructurally and mechanically to determine suitability for CS. Premature brittle fracture were seen in the deposits, necessitating processing improvements for enhanced deposit performance. Feedstock thermal pre-processing was explored, guided by thermodynamic modeling, to improve spray-ability. Heat treatments resulted in generalized powder softening, suggesting improved processability using a CS gas-particle dynamics model. This model allowed for theoretical tuning of processing parameters, predicting improved deposition using a specific configuration with He gas. The through-process model-informed experimental approach emphasizes the potential of using Addalloy 5T® powder in CS when coupling heat treatment with processing parameter optimization. Results suggest that the CS community may benefit from alloy design specifically for solid-state processing, tailoring powder chemistry and microstructure for enhanced properties and processability.