Thermoelectric non-destructive texture characterization in Ti-6Al-4V

Due to the manufacturing process Ti-6Al-4V alloy exhibited a very strong anisotropic texture caused by the existence of a preferred crystallographic orientation in the polycrystalline microstructure. This crystallographic alignment can result in anisotropic behavior of the material so that the material properties are different depending on whether they are measured in perpendicular or parallel direction. In addition to this morphological anisotropy, due to the dominantly hexagonal grain structure, the Ti-6Al-4V alloy also exhibited a substantial thermoelectric anisotropy. This study was conducted to investigate the effect of thermoelectric anisotropy on the thermoelectric power measurements in a highly textured Ti-6Al-4V specimen using a completely non-destructive technique based on the Seebeck effect. The result shows the thermoelectric power dependence associated with texturing and the macroscopic grain structure in a rolled Ti-6Al-4V specimen which was annealed at 710 °C for 2 h and slowly cooled. The measurements clearly demonstrate that the intrinsic sensitivity of the thermoelectric contact technique is a very useful tool that could be exploited for QND material characterization.