Abstract Scope |
Nb-Si based ultrahigh temperature alloys are expected to be used in the temperature range of 1200~1400 °C. After alloying with Ti, Hf, Zr, Cr, Al, the oxidation resistance of Nb-Si based alloys has been significantly improved. The master alloy ingot with the composition of Nb-22Ti-15Si-5Cr-3Al-2Zr-2Hf (at. %) was prepared by vacuum non-consumable arc melting followed by high-frequency water-cooled copper crucible induction melting. The alloys were subjected to static oxidation experiments at 600, 800, 1050, 1250 and 1350 ° C for 5, 10, 20, 50, and 100 hours respectively. The thickness of the scale and the weight gains per unit area were measured, and the oxidation kinetic curves of the alloy at different temperatures were plotted. The structure, phase constituents, composition distribution, and microstructure of the scale and internal oxidation zone of the specimens have been revealed. The oxidation behavior of Nb-Si based ultrahigh temperature alloys at different temperatures was elucidated. |