Selective laser melting (SLM) is a relatively new additive manufacturing process enabling complex shaped components to be manufactured that may not have previously been possible. The process involves sequential melting and solidification of metal powders until the part is built. The process generates a material with a complex micro structure which behaves very differently from conventionally manufactured materials when loaded. The deformation and failure behaviour of SLM materiel needs to be understood so that it can be predicted. This experiment will use neutron diffraction to understand the internal strain state in SLM material and how it evolves during elastic and plastic deformation in both monotonic and cyclic (tension and compression) loading conditions. The results will be used to and develop predictive micro-scale models of deformation in SLM materials of 316L steel.