Sensing of Ellipsoidal Inclusions in a Biomedical Ti–6Al–4V Alloy by Magnetic Means

Abstract

In this work, we conducted an experimental research to verify a developed analytical model based on the magnetic sensing of thermoelectric currents produced by ellipsoidal inclusions embedded in an inhomogeneous matrix under the influence of an external temperature gradient. By changing the aspect ratios b/a designated by e of the ellipsoidal inclusions, a wide range of real situations can be simulated. The aspect ratio of the ellipsoidal inclusions varied from 0.33 to 4. An external 1.8°C/cm temperature gradient in the bio-metallic specimen produced magnetic flux densities ranging from 2 to 150 μT at 1.5 mm lift-off distance between the tip of the magnetometer probe and the bio-metallic specimen. Due to the difference in the thermoelectric properties of the host (matrix) and the inclusion (imperfection), the temperature and electric field distributions will be distorted accordingly to the geometry of the inclusion; therefore, the magnetic signal produced by an inclusion will depend not only on its material properties and size, but also on its shape. The experimental magnetic field distribution illustrated the potential for the proposed thermoelectric coupling technique to detect and characterize metallic inclusions of different geometries based on their magnetic signature.