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钛合金的热氢处理(thermo-hydrogen treatment,THP)可以增加塑性相的体积分数,促进位错运动和降低流动应力,从而改善超塑性性能,有效降低钛合金的热加工难度,目前对钛合金热氢处理作用机理的解释多在晶粒和组织层面,少量电子结构层面的分析也不够明确,无法从本质上解释氢的固溶对α-Ti和β-Ti的致塑机理.本文运用固体与分子经验电子理论(empirical electron theory,EET)研究了氢在α-Ti,β-T_i的不同位置固溶时Ti的价电子结构变化,通过键距差方法(bond length diffrence method,BLD)计算得出了Ti原子间共价键电子对数、键能大小及滑移面间晶格电子密度,指出氢固溶后,滑移系上Ti-Ti键间共价电子对数、键能的明显下降及滑移面间晶格电子密度的增加是钛合金氢致超塑性的重要原因.
Titanium alloy thermo-hydrogen treatment (THP) can increase the volume fraction of plastic phase, promote the dislocation movement and reduce the flow stress, so as to improve the superplasticity and effectively reduce the difficulty of hot working titanium alloy. At present, The explanation of mechanism of hydrothermal treatment is mostly at the grain and tissue level, and the analysis of a small amount of electronic structure level is not clear enough to explain the mechanism of the solid solution of hydrogen on the formation of α-Ti and β-Ti.In this paper, With the empirical electron theory (EET), the valence electron structure of Ti during solid solution of α-Ti and β-T_i was studied by bond length diffrence method (BLD) The electronic logarithm of the covalent bond between Ti atoms, the size of the bond energies and the lattice electron density between the sliding surfaces were obtained. The covalent electron pairs of Ti-Ti bonds on the slip system and the bond energy The obvious decrease and the increase of the lattice electron density between the sliding surfaces are the important reasons for the hydrogen induced superplasticity of the titanium alloy.