Fruit Loops
Mackenzie Warwick
Graduate Student, College of Engineering
Medium
Digital photo – colorized microscopy image
Abstract
Irradiation creep is one of the life-limiting failure mechanisms of materials used to build nuclear power reactors. There are many proposed dominant mechanisms, all with somewhat contradictory explanations, and are not well characterized whatsoever. My thesis aims to fill this knowledge gap between what we think happens and what has actually happened using high resolution imaging techniques. The image shows the coupled relationship between high temperature (550℃), high stress (316 MPa), and radiation-induced damage which shows dislocation loop networks that contribute to radiation hardening and ultimately failure of the material. These experiments are conducted with 25 µm thick foils, a novel tapered specimen geometry to achieve multiple distinct stress states, irradiated with 3 MeV protons at the Michigan Ion Beam Laboratory (MIBL), and subsequently imaged using the resources at the Michigan Center for Materials Characterization.
The artistic components of this piece are a high resolution electron microscopy image taken at 47,000 times magnification, which was then inverted and overlaid with multiple colors. The image shows the coupled relationship between high temperature (550℃), high stress (316 MPa), and radiation-induced damage which shows dislocation loop networks that contribute to radiation hardening and ultimately failure of the material. This phenomenon is called irradiation creep, one of the life-limiting failure mechanisms of materials used to build nuclear power reactors. There are many proposed dominant mechanisms, all with somewhat contradictory explanations, and are not well characterized whatsoever. My thesis aims to fill this knowledge gap between what we think happens and what has actually happened using high resolution imaging techniques. These experiments are conducted with 25 µm thick foils, a novel tapered specimen geometry to achieve multiple distinct stress states, irradiated with 3 MeV protons at the Michigan Ion Beam Laboratory (MIBL), and subsequently imaged using the resources at the Michigan Center for Materials Characterization.