TY - JOUR
T1 - Residual stress mapping in Inconel 625 fabricated through additive manufacturing
T2 - Method for neutron diffraction measurements to validate thermomechanical model predictions
AU - Wang, Zhuqing
AU - Denlinger, Erik
AU - Michaleris, Panagiotis
AU - Stoica, Alexandru D.
AU - Ma, Dong
AU - Beese, Allison M.
N1 - Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2017/1/5
Y1 - 2017/1/5
N2 - The rapid solidification and subsequent thermal cycles that material is subjected to during additive manufacturing (AM) of a component result in a buildup of residual stresses, which lead to part distortion, and negatively impact the component's mechanical properties. We present a method for using neutron diffraction to validate thermomechanical models developed to predict the residual stresses in Inconel 625 walls fabricated by laser-based directed energy deposition. Residual stress calculations from neutron diffraction measurements depend strongly on the determination of stress-free lattice spacings. After measurement of stressed lattice spacings in Inconel 625 walls, reference samples were obtained by extracting thin slices from the walls and cutting comb-type slits into these slices. Reference lattice spacings were measured in these slices, as well as equivalent slices that were also subjected to stress-relieving heat treatment. These heat treatments changed the reference lattice spacings, and therefore affected residual strain measurements. Further, this study shows the importance of using location-dependent reference lattice spacing, as during AM, the thermal history, and therefore elemental composition and stress-free lattice spacing, vary with position. Residual stresses measured by neutron diffraction along the build direction using comb-type reference samples without heat treatment were in good agreement with thermomechanical modeling predictions.
AB - The rapid solidification and subsequent thermal cycles that material is subjected to during additive manufacturing (AM) of a component result in a buildup of residual stresses, which lead to part distortion, and negatively impact the component's mechanical properties. We present a method for using neutron diffraction to validate thermomechanical models developed to predict the residual stresses in Inconel 625 walls fabricated by laser-based directed energy deposition. Residual stress calculations from neutron diffraction measurements depend strongly on the determination of stress-free lattice spacings. After measurement of stressed lattice spacings in Inconel 625 walls, reference samples were obtained by extracting thin slices from the walls and cutting comb-type slits into these slices. Reference lattice spacings were measured in these slices, as well as equivalent slices that were also subjected to stress-relieving heat treatment. These heat treatments changed the reference lattice spacings, and therefore affected residual strain measurements. Further, this study shows the importance of using location-dependent reference lattice spacing, as during AM, the thermal history, and therefore elemental composition and stress-free lattice spacing, vary with position. Residual stresses measured by neutron diffraction along the build direction using comb-type reference samples without heat treatment were in good agreement with thermomechanical modeling predictions.
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U2 - 10.1016/j.matdes.2016.10.003
DO - 10.1016/j.matdes.2016.10.003
M3 - Article
AN - SCOPUS:84991688580
SN - 0264-1275
VL - 113
SP - 169
EP - 177
JO - Materials and Design
JF - Materials and Design
ER -