On the exploitation of thermoelectric coupling for characterization of elliptical inclusions in metals

A comparison between reported analytical results with experimental data of the magnetic flux density on cylindrical tin inclusions of elliptical cross-section embedded in a copper matrix under external thermal excitation is presented. By changing the aspect ratios b/a designated by e of the elliptical inclusions, a wide range of real situation such as slender inclusions can be simulated. The aspect ratio of the elliptical cylindrical inclusions varied from 0.50 to 3.250. A fairly modest 2.3 C/cm temperature gradient in the specimen produced magnetic flux densities ranging from 2 to 100 lT at 2 mm lift-off distance between the tip of the magnetometer probe and the specimen. The experimental magnetic field distribution illustrated the potential for the non contacting thermoelectric technique to detect and characterize metallic inclusions of different geometries based on their magnetic signature. Preliminary results on a cylindrical hard alpha (TiN) inclusion embedded in Ti–6Al–4V matrix is also presented to demonstrate that the proposed method might be applicable to a wide range of alloys including high-strength, high-temperature engine materials. 2012 Elsevier Inc. All rights reserved.