Effects of the alloying element Cr on the burning behavior of titanium alloys

The alloys C (Ti-35V-15Cr) and Ti40 (Ti-25V-15Cr-0.2Si) exhibit good burn resistance. However, the influence of the alloying element Cr on the burning behavior is not clear. The effects of the alloying element Cr on the itanium burning behavior are studied by means of the DCSB method. The results reveal that the burn resistance is improved when the Cr content is larger than 10%, especially larger than 15%. However, Binary Ti-Cr alloys do not exhibit burn resistant behavior. Their burning product surface is cracked and porous. The interface between the burning products and the matrix is also cracked if the Cr content is less than 10%, which can not retard oxygen diffusion into the matrix. The interface of Ti-(>10)Cr alloys is enriched with Cr, and Cr-oxides are tenacious, which can retard the oxygen diffusion into the matrix and decrease the burning velocity. The burning products of Ti-Cr alloys are TiO₂, TiO and TiCrO₃.