TiAl化合物反常屈服行为的键本质研究

Study of the Bond Structures of an Anomalous Yield Behavior in TiAl

摘要:

应用余氏理论计算了不同温度下有序与无序ＴｉＡｌ化合物的价电子结构，分析了温度升高而引起的晶格膨胀，长程有序度Ｐ和短程有序度ｒ下降对ＴｉＡｌ强度的影响。结果表明，ＴｉＡｌ化合物的Ｒ现象是温度直接影响价电子结构导致的强化与弱化综合作用的结果，而ｒ下降导致的“无序畴”形成将起到主要的强化作用。

Abstract:

By means of the Empirical Electron Theory (E E T), the valence electron structures of ordered and disordered TiAl at various temperatures are calculated. The effect of crystal lattice expansion and decrease of long -and short-rang order parameter (with increasing temperature) on strengthening is analyzed. The reason of an anomalous yield behavior in TiAl is that the valence electron structures directly effected by temperature result in strengthening, and "disorder domain" strengthening (with short order -range parameter descending). According to this view point, an mechanism is proposed, and some experimental results that content and grain size have influence on anomalous yield behavior in TiAl are explained.