Understanding process parameter-induced variability for tailoring precipitation behavior, grain structure, and mechanical properties of Al-Mg-Si-Mn alloy during solid-state additive manufacturing

• Published in: Materials & design 2024-09, Vol.245, p.113238, Article 113238
• Main Authors: Pariyar, Abhishek, Yasa, Evren, Sharman, Adrian, Perugu, Chandra S., Yuan, Liang, Hughes, James, Guan, Dikai
• Format: Article
• Language: English
• Subjects: Additive friction stir deposition (AFSD); Additive manufacturing; Mechanical properties; Microstructure; Process parameter
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2024.113238

[Display omitted] •AFSD causes dissolution and reprecipitation, inducing varied precipitation behavior due to parameters.•Extensive variation in the grain size, morphology, and recrystallization behavior occurs based on process parameter values.•A ∼70 % variation between the maximum and minimum nano/microhardness values was induced by the process parameters.•Tailoring the microstructure and mechanical properties is possible based on the process parameter combinations in this work. Additive friction stir deposition (AFSD), a solid-state additive manufacturing technique, has excellent industrial application potential, particularly for Al alloys. However, in-depth process parameter-microstructure-property correlations are lacking, especially regarding precipitation behavior. In this work, AFSD of Al-Mg-Si-Mn alloy with various process parameter combinations was performed to understand the variation (by ∼ 70 %) in the nano/microhardness, concerning the precipitation behavior. The low nano/microhardness sample exhibited dissolution of the β” strengthening phase. However, higher nano/microhardness samples showed varying microstructural features with high dislocation density owing to fine-scale pre-β” precipitation and another sample possessed inhomogeneous β” phase distribution and β’ precipitation at the grain boundaries, thus exhibiting reprecipitation during AFSD. The variation in the grain structure was such that the high nano/microhardness samples exhibited large, elongated grains (∼11 to 13 µm) and low recrystallization fractions (∼16 –18 %) suggesting a predominantly non-recrystallized microstructure. Conversely, the lowest nano/microhardness sample exhibited the smallest grain size (∼5 µm) and, a higher recrystallization fraction (∼42 %). These findings demonstrate extensive variation in the precipitation behavior, grain structure, and mechanical properties due to the process parameters. Future applications can leverage this knowledge to tailor the microstructure and mechanical properties based on the identified process parameter combinations.