Use of Positron Annihilation Spectroscopy for Stress-Strain Measurements
University of Nevada, Las Vegas
Las Vegas (Nev.)
Engineering metals and alloys, when subjected to tensile loading beyond a limiting value, undergo plastic deformation resulting in lattice defects such as voids and dislocations. These imperfections interact with the crystal lattice, producing a higher state of internal stress, also known as residual stress, which can be associated with reduced ductility. Residual stresses are also generated in welded structures due to rapid solidification and resultant dissimilar metallurgical microstructures between the weld and the base metals. Development of these internal stresses is often influenced by incompatible permanent strain resulting from thermal and mechanical operations associated with welding and plastic deformation. These types of operations can cause premature failures in structural materials unless these stresses are relieved by thermal treatments, which are commonly known as stress-relief operations.
This project is focused on the evaluation of residual stresses in target structural materials by the state-of-the-art destructive and non-destructive techniques. In addition, microstructural evaluations have also been performed by metallographic techniques. More recently, the effect of post-weld-thermal-treatments (PWTT) on the internal stresses in welded specimens has been studied. Further, the characterization of defects by transmission electron microscopy (TEM) has been performed.
Austenitic stainless steel; Deformations (Mechanics); Martensitic stainless steel; Nuclear reactors — Materials — Testing; Plasticity; Strains and stresses
Austenitic stainless steel; Martensitic stainless steel; Nuclear reactors--Materials--Testing
Materials Science and Engineering | Metallurgy | Nuclear Engineering | Oil, Gas, and Energy
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Roy, A. K.
Use of Positron Annihilation Spectroscopy for Stress-Strain Measurements.