Residual Stresses Induced by Laser FreeForm Fabrication

In this paper we report our attempts to use the neutron and X-ray diffraction techniques to characterize residual stresses in specimens manufactured by laser FreeForm technique. The aim of our work has been to understand how residua stresses develop during forming and their possible correlation with the microstructure, in particular the pore density which varies with the laser scan speed. The specimens under investigation were built by layer-sintering a ferritic-steel powder with a Cu-based-alloy powder as the binder material. Limited results have been obtained for the ferrite steel phase and are presented in the paper.