Interfacial Science of Nano-lamellar Materials

本文研究了α_2Ti_3Al相和γTiAl相组成的纳米片层材料的力学性能。这类材料含有大量的α_2/γ界面，阻碍了位错运动，提高了材料的强度。纳米片层材料的弹性极限对片层厚度λ不敏感，而无错配位的界面弹性极限较高。纳米片层材料的加工硬化率与λ成反比，错配位错的引入增加了加工硬化系数。高温暴露导致α_2/γ界面消失，导致纳米片层材料降解。加入β_0相形成元素后，α_2片层溶解后形成β_0相带。α_2片层消失后，析出带具有较高的蠕变强度。

The present research studied mechanical properties of nano-lamellar materials consisting of α_2Ti_3Al phase and γTiAl phase. This type of materials contains a large number of α_2/γ interfaces, which act as obstacles to dislocation motion and improve strength of such materials. Elastic limit of nano-lamellar materials is insensitive to lamellar thickness λ, but the interfaces without misfit dislocation provide a higher elastic limit. Work-hardening rate of nano-lamellar materials is inversely proportional to λ, and the coefficient is increased by the introduction of misfit dislocations. Disappearance of α_2/γ interfaces during high temperature exposure causes degradation of nano-lamellar materials. Bands of β_0 precipitates are formed after dissolution of α_2 lamellae when a β_0 phase forming element is added. The precipitation bands give high creep strength after the disappearance of α_2 lamellar.