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γ/γ界面对于(γ+α2)双相TiAl基合金的力学性能具有重要影响。本工作利用汇聚束电子衍射技术对一种含有Mn,Nb合金元素的(γ+α2)TiAl基合金中具有六种不同晶体学取向的γ相及γ/γ界面关系进行了实验唯一测定。结果表明,仅利用一套〈334〉高阶劳厄带花样就可以完全决定该合金中γ层片的晶体学取向。该合金中γ/γ界面有四种,即绕〈111〉旋转120°、旋转180°呈镜面对称真孪晶、旋转60°呈镜面对称的伪孪晶和反相畴界面。统计分析表明,真孪晶γ/γ界面的比例最高,伪孪晶γ/γ界面和旋转120°γ/γ界面较少。TiAl合金中偶尔也会出现γ/γ反相畴界。
The γ / γ interface has an important effect on the mechanical properties of (γ + α2) duplex TiAl-based alloys. In this work, the unique experimental determination of the γ phase and γ / γ interface with six different crystallographic orientations in a (γ + α2) TiAl-based alloy containing Mn and Nb alloying elements has been carried out by using cluster beam electron diffraction. The results show that the crystallographic orientation of the γ-lamella in this alloy can be completely determined using only a set of <334> higher order Laue bands. There are four kinds of γ / γ interface in the alloy, which are rotated by 120 ° and rotated by 180 ° with mirror-symmetric true twins and rotated by 60 ° with mirror-symmetric pseudo-twins and anti-domain interfaces. The statistical analysis shows that the ratio of true twin to γ / γ interface is the highest, and the number of pseudo twinned γ / γ interface and the rotated 120 ° γ / γ interface are less. Occasionally γ / γ antiphase boundaries appear in TiAl alloys.