Abstract
Severe residual stresses in metal parts made by laser powder bed fusion additive manufacturing processes (LPBFAM) can cause both distortion and cracking during the fabrication processes. Limited data is currently available for both iterating through process conditions and design, and in particular, for validating numerical models to accelerate process certification. In this work, residual stresses of a curved thin-walled structure, made of Ni-based superalloy Inconel 625™ and fabricated by LPBFAM, were resolved by neutron diffraction without measuring the stress-free lattices along both the build and the transverse directions. The stresses of the entire part during fabrication and after cooling down were predicted by a simplified layer-by-layer finite element based numerical model. The simulated and measured stresses were found in good quantitative agreement. The validated simplified simulation methodology will allow to assess residual stresses in more complex structures and to significantly reduce manufacturing cycle time.
| Original language | English |
|---|---|
| Pages (from-to) | 122-132 |
| Number of pages | 11 |
| Journal | Materials and Design |
| Volume | 135 |
| DOIs | |
| State | Published - Dec 5 2017 |
Funding
The neutron diffraction measurement was performed at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The authors from General Electric would like to thank America Makes project 4026 “Development of Distortion Prediction and Compensation Methods for Metal Powder-Bed AM” for providing the samples. K.A. and A.D.S. thank the support from an Laboratory Directed Research & Development project ( LDRD-7886 ) at ORNL .
Keywords
- Additive manufacturing
- Electron backscatter diffraction
- Finite element modeling
- Neutron diffraction
- Ni-based superalloy
- Residual stress
