Residual stress in additively manufactured Inconel cubes; Selective Laser Melting versus Electron Beam Melting and a comparison of modelling techniques

Abstract

Direct comparisons are made between the crystallographic texture and residual stress distribution within two otherwise identical Inconel cubes produced by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) additive manufacturing processes. In both respects, significant differences were observed; the SLM process produced a sample with high residual stress and cubic texture, while the EBM process generated negligible residual stress and a fibre texture. In the case of the SLM sample, the paper continues on to examine two different approaches to modelling the residual stress field; 1. a simplistic version based on an assumed radially symmetric isotropic eigenstrain, and 2. a layer-by-layer combined thermo-mechanical approach based on finite element modelling. Both models were able to capture the important overall features of the residual stress distribution, however the layer-by-layer approach showed more fidelity in the finer details.

Keywords

• Additive manufacture
• Residual stress
• Neutron diffraction
• Inconel