The individual effects of niobium and silicon on the oxidation behaviour of Ti3Al based alloys

Nitridation effects on the oxidation mechanisms of an ods Fe–Al intermetallic alloy

“…Upon the high temperature oxidation of titanium aluminides, TiN and/or Ti 2 AlN subscales have been observed to develop at the substrate/oxide interface [1,2], which sometimes have been referred to provide an effective barrier for outward Al diffusion [3] or to prevent oxygen dissolution in the alloy [4] thus improving their oxidation resistance. When these alloys are nitrided, the same nitrogen containing phases appear [5] but only detrimental effects have been reported to occur compared to non nitrided specimens owing to a lower amount of Al 2 O 3 developed at the top surface [6][7][8].…”

“…Pint et al [10] indicated that on Fe 3 Al this could result by either simultaneous nitridation and oxidation or, once the scale had been formed, by a reduced oxygen partial pressure in contrast to a high nitrogen pressure. The latter mechanism seems to better agree with the findings of Xu et al on FeAl [11].…”

“…However, the effects of nitridation have only been scarcely studied. Choe [12] employed ion implantation at 150 keV to nitride different Fe 3 Al (with and without Cr, Mo and B) resulting in the formation of AlN, Fe 4 N, CrN and even α-Fe, which enhanced the corrosion resistance to acid media. More recently, the effects of an ion nitriding treatment on the oxidation behaviour of an ODS FeAl alloy have been discussed [13], indicating the formation of AlN and again of α-Fe after the nitridation treatment, the latter element diffusing outwardly upon oxidation to form iron oxides.…”

The Isothermal Oxidation Behavior of a Ti3Al-Nb-V-Mo Alloy

“…Actual applications in the aerospace industry and laminated compositions require the alloys to be considered in a variety of high-temperature environments. Most work on the oxidation behavior of Ti 3 Al-based alloys concerns the effect of the alloying elements Nb and Si on improvement of oxidation resistance by surface modification [6][7][8][9][10][11][12], however, the effect of microstructure on the oxidation behavior of 14at.%Nb-containing Ti 3 Al-based alloy is still lacking. The formation mechanism and microstructural development of the O-phase as well as the tensile deformation and fracture behavior of Ti 3 Al-Nb alloy have been previously studied by Wu et al [13][14][15][16].…”

Oxidation mechanisms of low energy-high flux nitrided ODS FeAl intermetallic alloy

“…Upon the high temperature oxidation in air of TiAl intermetallic alloys, nitridation is observed between the oxide scale and the substrate [1,2] improving their oxidation resistance [3,4].…”