摘要
针对纳晶金属材料的氢脆问题,该文提出一个新的理论模型。在该模型的理论框架内,认为堆积在距裂纹尖端最近晶界上的氢原子会阻止位错从裂纹尖端的发射,从而抑制裂纹的钝化,同时促进纳晶金属材料的脆性断裂。该文在有氢和无氢两种条件下,对纳晶镍的临界应力强度因子与晶粒尺寸之间的相互关系进行了对比。结果表明:由于氢原子的脆化作用,纳晶镍的临界应力强度因子下降30%之多,这种氢致纳晶金属材料脆化的现象随其晶粒尺寸的变小而愈加显著。
In this paper, a new theoretical model on hydrogen embrittlement of nanocrystalline metals is proposed, in which hydrogen atoms are assumed to accumulate in the nearest grain boundary ahead of the nanocrack tip; they prevent the emitting of dislocations from crack tip, and thus suppress nanocrack tip blunting as well as induce brittle fracture. The dependence of the critical stress intensity factor on grain size with and without hydrogen in nanocrystalline Ni is clarified and compared. The results show that the ingress of hydrogen into nanocrystalline metals results in a drop in critical stress intensity factor by more than 30% in contrast with the hydrogen free condition, and this hydrogen-induced embrittlement in nanocrystalline metals is especially remarkable with the reduction of grain size.
出处
《工程力学》
EI
CSCD
北大核心
2014年第12期228-233,共6页
Engineering Mechanics
基金
国家自然科学基金项目(10872087)
教育部新世纪优秀人才支持计划项目(NCET-12-0712)
霍英东青年教师基金项目(101005)
关键词
纳晶金属材料
脆性断裂
位错发射
氢脆
裂纹
nanocrystalline metals
hydrogen embrittlement
brittle fracture
dislocation emission
crack
