A comparative study of the impurity segregation from commercially pure Ti, Ti6Al4V and Ti3Al8V6Cr4Zr4Mo

The surface composition of commercially pure Ti, Ti6Al4V and Ti3Al8V6Cr4Zr4Mo during annealing at different constant temperatures was experimentally investigated. Auger electron spectroscopy was used to monitor the APPHs of the specified elements present on the surfaces. The surfaces of Ti and its alloys were contaminated by oxygen and carbon, and the contamination is attributed to the continual uptake of the background gases, even in the UHV chamber. It was found that mainly C and S segregated at 400 degrees C, and Cl at higher temperatures (500-630 degrees C) for commercially pure Ti. However, S was the main segregating species for all three samples. The segregation of Al was measured for the Ti6Al4V and Ti3Al8V6Cr4Zr4Mo samples at higher temperatures. The linear least-square fit method was employed to determine the contribution of pure Ti and TiC from the measured APPH's. The AES fitting confirmed the formation of TiC on the surface at temperatures 400-500 degrees C. (c) 2006 Elsevier B.V. All rights reserved.