Stress distributions in multilayer laser deposited Waspaloy parts measured using neutron diffraction

During layered manufacturing of functional metallic parts by laser direct metal deposition (LDMD) residual stresses are generated by the transient thermal fields. Various methods to reduce or control the development of these stresses have been previously attempted. This paper reports a novel method using the pulse parameters of a diode laser deposition system as a tool for residual stress control. Stresses in LDMD manufactured Waspaloy blocks are calculated from strain measurements in three directions carried out at the neutron diffraction beam line SALSA at the European ILL facility, Grenoble, France. The results show tensile stresses close to the top of the structures of similar magnitude for all parameters and large compressive stresses normal to the deposition surface close to the base.