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The purpose of this collaborative research project involving the University of Nevada, Las Vegas (UNLV) and Idaho State University (ISU) is to evaluate the feasibility of determining residual stresses of welded (after pre-straining) engineering materials using a new nondestructive technique based on positron annihilation spectroscopy. The proposed technique is to use γ-rays 2 from a small MeV electron Linac to generate positrons inside the sample via pair production. This method can be used for materials characterization and investigation of defects in thick samples that could not be accomplished by conventional positron techniques or other nondestructive methods. The data generated will be compared to those obtained by other methods such as neutron diffraction (for thin samples only) and ring-core techniques. Materials to be tested in the initial phase will be unirradiated austenitic (Type 304) and martensitic (EP- 823) stainless steels that will be cold-worked and welded prior to the evaluation of their residual stresses. Metallurgical microstructures will also be evaluated. Later, irradiated austenitic materials (Type 316L stainless steel and Alloy 718) may be included in this program.


Austenitic stainless steel; Deformations (Mechanics); Martensitic stainless steel; Nuclear reactors — Materials — Testing; Plasticity; Strains and stresses; Welded joints — Fatigue


Materials Science and Engineering | Mechanical Engineering | Metallurgy | Nuclear Engineering | Oil, Gas, and Energy