腐蚀疲劳断裂过程中氢与缺陷相互作用的正电子湮没研究  

Investigation of interaction between hydrogen and defects in corrosion fatigue fracture process by positron annihilation

作　　者：俞方华[1] 郑文龙[2] 苏立民[2] 朱锡英[2] 闵国全[2] 项开华 

机构地区：[1]中国科学院上海原子核研究所,上海201800 [2]上海材料研究所,上海200437 [3]同济大学,上海200092

出　　处：《核技术》1993年第6期325-330,共6页Nuclear Techniques

基　　金：中国科学院腐蚀科学开放研究实验室课题

摘　　要：用正电子湮没谱研究了40CrNiMo低合金高强钢海水腐蚀疲劳断裂后,低温释氢过程中正电子湮没H参数和寿命参数随温度的变化。实验表明H-T和寿命参数-T曲线有三个极点,分别对应于氢从晶界、位错和微空洞处释出。第一阶段断裂区晶界释氢和位错释氢多于第二阶段区。而微空洞释氢则第二阶段多于第一阶段。晶界与氢相互作用能较有利于氢沿晶界运动,促使氢致开裂沿晶发展。位错与氢相互作用使位错增殖并有利于氢的输运。氢与微洞作用促使微空洞尺寸和数目在几小时内达到并超过空气疲劳200多小时的水平,并促进腐蚀疲劳第二阶段快速断裂。估计了氢与晶界、位错和微空洞的结合能,并结合电镜结果进行了讨论。Two fractured samples one corroded in artificial seawater and the other in air, have been investigated by positron annihilation spectroscopy. Both samples released hydrogen in the temperature regions from RT to 200℃ and from RT to 400℃, respectively. The results indicated that hydrogen enhanced fatigue defects and shielded from positrons localized in defects. From the deep points of the H- T and I2- T curves, it was discovered that hydrogen was released from grain boundary, dislocations and microvoids, respectively. In the first cracking stage grain boundary released more hydrogen than in the second stage. The interaction between hydrogen and microvoids made the volume and number of voids enlarge faster. The binding energies of hydrogen with grain boundary, dislocations and microvoids were estimated. The effect of hydrogen on corrosion fatigue fracture was discussed using da/dN-△K curve and SEM fracture appearance.

关 键 词：氢 缺陷 腐蚀 疲劳断裂 正电子湮没 

分 类 号：TG111.91[金属学及工艺—物理冶金]