氢固溶对钛合金超塑性影响的价电子结构分析

发布时间：2018-03-02 07:05

本文关键词： 氢固溶超塑性钛合金价电子结构固体与分子经验电子理论　出处：《中国科学:技术科学》2017年04期 　论文类型：期刊论文

【摘要】：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.
[Abstract]:The thermo-hydrogen treatment of titanium alloy can increase the volume fraction of the plastic phase, promote dislocation movement and decrease the flow stress, thus improve the superplasticity and effectively reduce the difficulty of hot processing of titanium alloy. At present, the explanation of the mechanism of hot hydrogen treatment for titanium alloys is mostly at the grain and microstructure levels, and the analysis of a small amount of electronic structures is not clear enough. It is impossible to explain the plasticizing mechanism of hydrogen solution on 伪 -Ti and 尾 -Ti in essence. In this paper, the valence electron structure changes of Ti in different locations of 伪 -Ti, 尾 -Ti have been studied by using the empirical electron of solid and molecular electron theory. The covalent electron logarithm, bond energy and lattice electron density between slip planes of Ti atoms were calculated by bond length diffrence method BLDs. It is pointed out that after hydrogen solution, the covalent electron logarithms of Ti-Ti bonds on slip systems are obtained. The decrease of bond energy and the increase of lattice electron density between slip surfaces are the important reasons for hydrogen induced superplasticity of titanium alloys.
【作者单位】：清华大学机械工程系;清华大学摩擦学国家重点实验室;清华大学航空航天学院;
【基金】：国家自然科学基金(批准号:51471090)资助项目
【分类号】：TG146.23

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