The Microstructural Evolution of Rapidly Solidified Powder Aluminum 2024 During Thermal Processing

Gas-atomized metallic powders are commonly used in solid-state deposition processes, such as cold spray and additive friction stir. While their post-process consolidated properties are widely studied, there is little research on the properties of the powders before processing. Understanding the powder characteristics before use in additive manufacturing could lead to fine-tuning properties of additively manufactured materials. This research studied the effect of various thermal treatment processes on the characteristics and microstructural evolution of powder aluminum alloy 2024. Treatment times and temperatures were guided by thermodynamic modeling. Light microscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, electron backscatter diffraction, and differential scanning calorimetry were used to evaluate each condition. Thermodynamic models were used to predict the phase stability in these powders and were calibrated using the experimental results to give a more complete understanding of the phase transformations during thermal processing.