The non-isothermal oxidation characteristic and the microstructure of the oxidation products were systematically studied by TGA/DSC test methods associated with XRD,SEM and EDS analysis methods. Further, the influence mechanism of vanadium and chromium elements on the non-isothermal oxidation resistance of Ti-V-Cr type fireproof titanium alloys was discussed. The results show that, from room temperature to 1723K, the non-isothermal oxidation resistance obviously decreases with increasing of vanadium content. Simultaneously, the oxidation film thickness increases from 168μm to 370μm, and the oxidation film thickness of Ti-35V alloys is about 1.45 times that of Ti-25V alloys; whereas the non-isothermal oxidation resistance of Ti-V-Cr type fireproof titanium alloys gradually increases with increasing of vanadium content and the differences among these alloys are quite small. The oxidation film thickness changes from 110μm to 85μm, and the thickness of Ti-35V-15Cr decreases about 15.5% than that of Ti-25V-15Cr alloy. The non-isothermal oxidation resistance of Ti-V-Cr alloys is much higher than that of Ti-V alloys, and the main reasons are that the liquid V2O5 formed during non-isothermal oxidation greatly releases the inner stress of oxidation film, which improves the combination ability between oxidation film and alloy matrix and also prevent together with Cr2O3 and TiO2 the massive diffusion of oxygen to the alloy matrix. The non-isothermal oxidation resistance characteristic of Ti-V-Cr fireproof titanium alloys is described quantitatively by non-isothermal oxide mass gain curve and oxidation film thickness, which are consistent with the results of friction ignition test. Therefore, the fireproof property of titanium alloy can be predicted.
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