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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。据此提出了“无序畴”强化机制并圆满地解释了成分、晶粒度等因素影响TiAl化合物R现象的一些实验结果。
The valence electron structures of ordered and disordered TiAl compounds at different temperatures were calculated by Yu’s theory. The effects of lattice expansion, long-range order degree P and short-range order degree r on TiAl strength were analyzed. The results show that the R phenomenon of TiAl compounds is the result of the direct effect of temperature on the combined effect of strengthening and weakening caused by the valence electron structure, and the formation of “disordered domains” due to the decrease of r will play a major role in strengthening. Based on this, the mechanism of “disordered domains” is proposed and some experimental results, such as composition and grain size, which affect the phenomenon of TiAl compound R, are satisfactorily explained.