The Influence of Pre-oxidation in a Silica-powder Pack on the Cyclic Oxidation Behavior of High Nb-TiAl Alloys
The lightweight TiAl alloys exhibit a large number of outstanding properties at high temperature. However, the actual service of TiAl alloy has been hindered by their poor oxidation resistance above 700℃. Nb addition is benefit to the oxidation resistance of TiAl, while pre-oxidation under low oxygen pressure at high temperature is an effective measure for improving the oxidation resistance of TiAl alloys. Considering the differences of oxidation behavior between high Nb-TiAl and TiAl alloys, the influence of pre-oxidation on the cyclic oxidation behaviors of high Nb-TiAl alloys was investigated in air at 900℃. The pre-oxidation was performed by heating the specimens,buried in silica powder and encapsulated in a silica tube under a vacuum of 1.3×10-3 Pa,at 9001050℃ for 16 hours. The scales formed by preoxidation were very adherent and protective. After cyclic oxidation for 200 cycles (200 hours), the mass gain of pre-oxidized alloy was about 10％-40％ of that of untreated alloy. The least mass gain had been got at the 1050℃. This excellent oxidation resistance is attributed to the formation of dense Al2O3-rich layer and the extremely dense rutile layer.
Preoxidation titanium aluminides (TiAl) pack treatment
Pengfei Sun Li Zhang Junpin Lin Guoliang Chen
State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1902-1905
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）