NDI System for Quantification of Subsurface Residual Stress in the Laboratory

The goal of the proposed research is to develop a non-destructive method for subsurface residual stress measurement in turbo-machinery components. Neutron diffraction techniques have a proven ability to determine residual stresses at significant depths, however implementation of these techniques has been limited to specialized facilities such as the High Flux Isotope Reactor (HFIR) neutron at Oak Ridge National Lab. Advances in laboratory based neutron generators have now made it possible to implement some of these techniques in laboratory and production environments. We will exploit the improved ca-pabilities of these generators to realize a practical method that will enable determination of residual stresses within bulk materials. The proposed method will combine advantages of conventional in-situ neutron diffraction with energy selective neutron imaging to reveal microstructural information related to the lattice spacing such as phase, texture, and strain. This Phase II program will extend research to de-velop the measurement technique further and work towards the implementation of a practical system. To successfully develop this highly rewarding technology, we have formed a strong consortium that in-cludes a world renowned expert in residual stress measurements using neutron and X-ray techniques and an OEM for turbo-machinery, which will effectively address current needs of the Navy.