氢固溶对钛合金超塑性影响的价电子结构分析  

The valence electron structure analysis on the influence of hydrogen solid solution to the thermoplasticity of a-Ti and β-Ti

作　　者：魏亚蒙 吕志刚[1,2] 何良菊[3] 李培杰[1,2] 

机构地区：[1]清华大学机械工程系,北京100084 [2]清华大学摩擦学国家重点实验室,北京100084 [3]清华大学航空航天学院,北京100084

出　　处：《中国科学：技术科学》2017年第4期411-417,共7页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:51471090)资助项目

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.The therrno-hydrogen （THP） of titanium can improve the thermoplasticity performance by increasing volume fraction of the plastic phase, promoting the movement of dislocations and reducing the flow stress. It can significantly reduce the difficulty of titanium alloy hot working. Most of the explainations on THP remain at the grain and phase scale and some researches at the electron scale are not clear enough, which cannot fully reveal the mechanism of hydrogen induced thermoplasticity of titanium. Empirical electron theory （EET） of solids and molecules was applied to analysis the changes of valence electron structures when H dissolved into different interstices of α-Ti or β-Ti. Through bond length diffi＇ence method （BLD）, the the number of covalent bonding electron pairs between Ti-Ti, the energy of the chemical bond and the lattice electron density between glide planes were calculated, it can be got that the obvious decrease of he number of covalent bonding electron pairs and the energy of the chemical bond between Ti-Ti, and the increase of the lattice electron density between glide planes are the essential reasons of hydrogen induced thermoplasticity of titanium.

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 

分 类 号：TG146.23[一般工业技术—材料科学与工程]