Noncontacting Thermoelectric Detection of Material Imperfections in Metals
Abstract
A unique nondestructive materials characterization facility has been established for non-contacting thermoelectric inspection of metals. The measurement system is based on a high-temperature SQUID magnetic scanner that is capable of detecting the weak magnetic field of thermoelectric currents developing around material imperfections when a conducting metal is subjected to external heating and cooling. Since the surrounding intact material serves as the reference electrode and there is no artificial interface between the host and the imperfect region to be detected, the inspection sensitivity is much higher than that of conventional thermoelectric systems. This new nondestructive inspection technique offers the following distinct advantages over conventional methods: (1) high sensitivity to subtle variations in material properties; (2) insensitivity to the size, shape, and other geometrical features of the specimen; (3) noncontacting nature with a substantial stand-off distance; and (4) the ability of probing deep into the material and penetrating through thick, multiple-layer structures. The potential applications of this method include detection of metallic inclusions, segregations, inhomogeneities, and tight cracks as well as quantitative characterization of hardening, fatigue, texture, and residual stresses.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2004
- Accession Number
- ADA423831
Entities
People
- Peter B. Nagy
Organizations
- University of Cincinnati