(1. 北京科技大學 新金屬材料國家重點實驗室， 北京 100083；
2. Materials Research Division, Universal Energy Systems, Dayton, Ohio 45432, U.S.A)
摘 要: 研究了Nb對γ-TiAl基合金性能的影響， 結果表明， 高Nb合金化能大大提高γ-TiAl基合金的高溫強度，合金含Nb量越高， 強度就越高。 TEM觀察表明， Nb對γ-TiAl性能的影響類似于氧元素， 增強d—d鍵的方向性， 增加普通位錯的P-N力， 提高普通位錯開動的臨界分切應力和滑移阻力。 Al對γ-TiAl合金性能的影響是通過影響合金中的α2相含量來影響其性能的。 隨合金中Al含量升高，α2 相含量減少， 位錯運動非熱激活阻力降低， 合金的強度下降。
關鍵字: Nb； Al； TiAl基合金； 高溫強度
（1. State Key Lab for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083， P.R.China；
2. Materials Research Division, Universal Energy Systems, Dayton, Ohio 45432）
Abstract:It is shown from the effect of Nb on γ-TiAl based alloys that highNb content can improve the high temperature yield strength greatly, the higher the content of Nb in TiAl based alloys, the better the strength. TEM analysis shows that the highNb solution in γ phases can enhance the directionality of d—d bonds and therefore enhance the P-N stresses so as to increase theCRSS for ordinary dislocation slip, leading to a higher lattice frictional resistance. The aluminium content has a significant effect on the high temperature yield strength of TiAl based alloys as a result of the changed α2 content. The athermal activating stress of dislocation slip decreases as Al content increases which results in the decrease of the α2 content, and the high temperature strength of TiAl based alloys decreases.
Key words: Nb； Al； TiAl based alloys； high temperaturestrength
