Experimental observation of stress formation during selective laser melting using in situ X-ray diffraction

technology, process-related defects, distortions and residual stresses impede its usability for fracture-criticalapplications. In this paper, results of in situ X-ray diffraction experiments are presented that offer insights intothe strain and stress formation during the manufacturing of multi-layer thin walls made from Inconel 625. Usingdifferent measuring modes and laser scanning parameters, several experimental observations are discussed tovalidate and extend theoretical models and simulations from the literature. As a sample is built-up layer by layer,the stress state changes continuously up until the last exposure. The localized energy input leads to a complexstress field around the heat source that involves alternating tensile and compressive stresses. The correlation oftemperature and yield strength results in a stress maximum at a certain distance to the top layer. The presentstudy demonstrates the potential of high-energy synchrotron radiation diffraction for in situ SLM research