High-temperature oxidation behavior of TaTiCr, Ta4Ti3Cr, Ta2TiCr, and Ta4TiCr3 concentrated refractory alloys
Noah J. Welch, Maria J. Quintana, T.M. Butler, Peter C. Collins
Abstract
This study reports the unique microstructures and high-temperature oxidation behavior of TaTiCr, Ta 4 Ti 3 Cr, Ta 2 TiCr, and Ta 4 TiCr 3 concentrated refractory alloys and elucidates the effect of moderate composition changes on oxidation performance. All alloys investigated in this study formed bcc solid solution matrices with second phase Laves precipitates (except for Ta 4 Ti 3 Cr, being single-phase bcc). The alloys were tested for 24 h at 1200 °C, of which: TaTiCr exhibited superior oxidation performance for the duration of the test; Ta 4 TiCr 3 showed moderate oxidation resistance , with both parabolic and linear kinetic regimes; and Ta 4 Ti 3 Cr and Ta 2 TiCr both exhibited poor oxidation performance, with Ta 2 TiCr being completely oxidized after testing. All alloys formed complex oxides ; however, the excellent performance of the TaTiCr alloy can be attributed to the compact, continuous nature of the oxide scale , the combination of complex oxides and protective Cr 2 O 3 formation, and the complex internal nitride morphology, slowing oxygen ingress and reducing the depth of internal oxidation.