Protection of titanium alloys against high temperature oxidation during closed-die forging: Structural analysis of the boro-silicate glass coating/Ti-6Al-4V alloy interfacial region by correlative imaging

We analyse herein the interfacial region formed between a borosilicate glass coating and Ti-6Al-4V alloy after a transient of 8 h at 1150 degrees C. The correlation of two optical and electron microscopy methods (Raman and Backscatter Electron Diffraction imaging) enabled an accurate description of this particular interface. This interface is composed of five different phases, namely Ti2O3, TiB2, TiB, Ti5Si3 and Ti6Si2B, and it proves to be protective against oxygen permeation. Finally, this study also enabled the development of a Raman database for Ti borides, silicides, and borosilicides, in part from experimental and more completely from theoretical (DFT computations) data.

Automated summary

In this study, the interfacial region between a borosilicate glass coating and Ti-6Al-4V alloy at high temperature was accurately described using a combination of Raman and Backscatter Electron Diffraction imaging. This interface consists of five different phases, including Ti2O3, TiB2, TiB, Ti5Si3, and Ti6Si2B, which provide protection against oxygen permeation. Additionally, a Raman database for Ti borides, silicides, and borosilicides was developed using experimental and theoretical (DFT computations) data.