Recrystallization behavior and mechanical properties of Haynes 282 fabricated by wire-arc additive manufacturing with post-heat treatment

• Published in: Journal of manufacturing processes 2024-06, Vol.119 (C), p.781-789
• Main Authors: Pizano, Luis Fernando Ladinos, Sridar, Soumya, De Vecchis, Rafael Rodriguez, Wang, Xin, Biddlecom, Jacob, Pataky, Garrett J., Sudbrack, Chantal, Xiong, Wei
• Format: Article
• Language: English
• Subjects: Hot isostatic pressing; Recrystallization; Scan vector length; Tensile strength; Texture
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2024.04.015

In the pursuit of enhancing the mechanical properties of Ni-based superalloys manufactured using additive manufacturing, it is important to mitigate microstructural heterogeneities and structural flaws by optimizing the scanning strategy and post-processing. The present work investigates the influence of scan vector length on the as-printed microstructure and recrystallization behavior of Haynes 282 designed by wire arc additive manufacturing (WAAM). The lengths of the scan vectors used in this work were 25 and 100 mm. Moreover, we studied the effect of hot isostatic pressing (HIP) and subsequent aging heat treatment on the evolution of microstructure and mechanical properties. The outcomes of our study reveal that longer scan vectors induce high cooling rates, leading to a finer grain structure and accelerated recrystallization kinetics in WAAM Haynes 282. Conversely, shorter scan vectors yield coarser microstructures accompanied by stronger texture. HIP reduces the porosity to ∼1 % and is accompanied by γ' precipitation during the furnace cooling, which can be dissolved during initial aging at 1010°C and subsequently reprecipitated via secondary aging, thereby increasing the hardness. Tensile tests unveiled that those specimens subjected to HIP exhibit yield strength at par with wrought Haynes 282. This research highlights the significance of optimizing scanning strategies and post-heat treatments to tailor the microstructure and improve the mechanical properties of Haynes 282 fabricated by WAAM. [Display omitted] •Short scan vectors reduce the build cooling rate, resulting in coarse, textured grain structures.•High cooling rates during solidification boost the recrystallization kinetics.•HIP together with aging improves the strength of WAAM Haynes 282.