Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7993002 | Journal of Alloys and Compounds | 2018 | 19 Pages |
Abstract
Porous TiAl alloys are anticipated to become next-generation high temperature structural filtration materials due to their promising applications in the field of high temperature gas/solid and liquid/solid two-phase separation. However, poor high temperature oxidation resistance at elevated temperatures greatly limits the use of the alloys for practical applications. Here, a novel TiAl/Ti3Al/Nb2Al/Ti5Si3/Al2O3 porous composite with hierarchical micro-pore structure has been developed by manipulating chemical reactions to improve the anti-oxidation properties of high Nb-TiAl-based alloys at elevated temperatures. Several characterization methods were used to investigate the phase transformation mechanism of the porous composites, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectrometry (EDS). The results show that the porous composites possess slow oxidation kinetics and the weight gain during oxidation declines as the Nano-SiO2 content increases after the 900â¯Â°C/100â¯h isothermal treatment. A minimum weight gain of 3.68â¯g/m2 is achieved for the composite with 6â¯wt% Nano-SiO2 particles after the isothermal treatment. The porous composite's excellent anti-oxidation properties are mainly attributed to the synergistic effect of Al2O3 and Ti5Si3 generated by the Nano-SiO2 reaction of TiAl and Ti3Al, which suppresses the O inward diffusion and Ti outward diffusion. This study provides additional insights into high temperature applications of TiAl-based porous alloys.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Wanyuan Gui, Yongfeng Liang, Guojian Hao, Junpin Lin, Dayang Sun, Mengdi Liu, Chang Liu, Hui Zhang,