Jun-Sang Park

Non-Destructive Characterization of Engineering Materials Using High-Energy X-rays at the Advanced Photon Source

Engineering materials are typically made from transition metals and exist in polycrystalline form. The ability to characterize this class of materials, both ex situ and in situ, is particularly important as the demand for efficient, environment-friendly machines rises and the need to understand the material response at a smaller length scale increases. In the past decade, the use of high-energy synchrotron X-rays to characterize bulk engineering materials has increased significantly, with several high-energy beamlines and new characterization techniques coming online around the world.

Non-Destructive Internal Lattice Strain Measurement Using High Energy Synchrotron Radiation

High energy synchrotron X-rays can penetrate large samples and real engineering components. Taking advantage of this capability, diffraction techniques using monochromatic X-rays have been widely used to measure the residual strains in engineering components. However, isolating a particular volume inside a large component and measuring the residual strain is a challenge when employing typical monochromatic X-ray techniques. In this work we describe a spiral slit system capable of isolating an interior volume in a polycrystalline sample and non-destructively measuring the lattice strains in the volume. An interference fit sample constructed from a Ni-based superalloy is used to demonstrate the capabilities of the system. We compare the strain results to those measured using a conical slit system, a more mature and established device. The results from several polycrystalline samples with non-cubic crystal symmetry are also presented.