• Schell, Norbert
• Filho, João Da Cruz Payão
• Avila, J. A.
• Oliveira Felice, Igor
• Maawad, Emad
• Santos, Telmo G.
• Duarte, Valdemar R.
• Li, J. Y.
• Zhang, Y.
• Farias, Francisco Werley Cipriano
• Oliveira, João Pedro

Abstract

<p>The typical as-built coarse and cube-oriented microstructure of Inconel® 625 parts fabricated via arc-based directed energy deposition (DED) induces anisotropic mechanical behavior, reducing the potential applications of arc-based DEDed Inconel® 625 in critical components. In this sense, the present work aimed to reduce the grain size and texture by applying an in situ interlayer hot forging (HF) combined with post-deposition heat treatments (PDHT). The produced samples were characterized through optical microscopy, scanning electron microscopy coupled with electron backscatter diffraction, synchrotron X-ray diffraction, and Vickers microhardness. Also, a dedicated deformation tool was designed and optimized via a finite element method model considering the processing conditions and thermal cycle experienced by the material. It is shown that the in situ interlayer deformation induced a thermo-mechanical-affected zone (dynamic recrystallized + remaining deformation, with a height of ≈ 1.2 mm) at the bead top surface, which resulted in thinner aligned grains and lower texture index in relation to as-built DED counterpart. In addition, the effects of solution (1100 °C/ 1 h) and stabilization (980 °C/ 1 h) PDHTs on the Inconel® 625 HF-DEDed parts were also analyzed, which promoted fine and equiaxed static recrystallized grains without cube orientation, comparable to wrought material. Therefore, the HF-DED process significantly refined the typical coarse and highly oriented microstructure of Ni-based superalloys obtained by arc-based DED.</p>

Topics

• Deposition
• impedance spectroscopy
• surface
• grain
• grain size
• scanning electron microscopy
• x-ray diffraction
• anisotropic
• texture
• electron backscatter diffraction
• optical microscopy
• directed energy deposition
• forging
• superalloy
• aligned