晶粒尺寸对304L奥氏体不锈钢氢脆的影响  

Effect of Grain Size on Hydrogen Embrittlement of 304L Austenitic Stainless Steel

作　　者：王艳飞[1] 李耀州 黄玉婷 谢宏琳 吴炜杰 WANG Yanfei;LI Yaozhou;HUANG Yuting;XIE Honglin;WU Weijie(School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou 221116,China;Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学化工学院,徐州221116 [2]北京科技大学新材料技术研究院,北京100083

出　　处：《中国腐蚀与防护学报》2023年第3期494-506,共13页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金(52175205)。

摘　　要：考虑到在预充氢与动态充氢两种加氢条件下的氢扩散、陷阱与位错运动的相互影响存在差异,本文通过重度冷轧和退火处理制备了不同晶粒尺寸的304L不锈钢试样,采用单轴拉伸实验对比研究了预充氢和动态充氢两种条件下晶粒尺寸对钢HE敏感性的影响,并结合断口分析从氢陷阱、氢浓度的角度分析了晶界的作用。结果表明,动态充氢下,表面裂纹扩展和位错运动能够提高氢的有效扩散系数并加速氢进入试样内,但随着晶粒尺寸降低,由于晶界陷阱作用增加,氢的有效扩散系数降低,同时由于进入试样的氢被大量晶界陷阱瓜分使氢分布均匀化,使每个晶界处的局部氢浓度降低,因此动态充氢条件下晶粒细化抑制钢的HE。相反,预充氢条件下晶粒细化增加HE,因为较长的预充氢时间(96 h)使大量氢进入细晶试样并存储于晶界陷阱内,提高了晶界氢浓度,在后续拉伸过程中,晶界作为氢源向新生位错供氢,因此导致了细晶试样的HE敏感性反而更高。The effect of hydrogen pre-charging and in situ charging on performance of the charged steel is different due to the diverse interactions between hydrogen diffusion,trapping and dislocation movements for the two processes.In this paper,304L austenitic stainless steels of different grain size were produced by heavy cold-rolling and annealing treatment,and then their hydrogen embrittlement behavior were investigated by tensile tests,while the testing steels were subjected to either hydrogen precharging or in-situ charging.The results showed that,during tensile testing by in situ hydrogen charging,the emerging surface cracks and dislocation movements could increase effective hydrogen diffusivity,meanwhile,the entering hydrogen is absorbed by a large number of grain boundary traps in the steel to homogenize the distribution of hydrogen,which leads to the relative decrease of local hydrogen concentration for each grain boundary.Therefore,grain refinement can inhibit the hydrogen embrittlement tendency of steel during tensile test while dynamic hydrogen charging.On the contrary,a long pre-charging time(96 h)makes a large amount of hydrogen enter the fine-grained steel and store in the grain boundary traps,which increases the concentration of hydrogen in grain boundaries.In the subsequent tensile testing,the grain boundaries serve as a source to supply hydrogen to the newly generated dislocations,resulting in a higher sensitivity of fine-grained steel to hydrogen embrittlement.Indeed,for the steel subjected to pre-charging hydrogen,no evident of decrease in hydrogen concentration of grain boundaries was indicated after grain refinement.As the steel being subjected to pre-charging,each grain boundary contained a high amount of hydrogen,which may act as source for delivery of hydrogen to the newly generated dislocations,therefore,grain refinement enhanced the HE of fine-grained steels.

关 键 词：氢脆 奥氏体不锈钢 晶粒尺寸 氢陷阱 

分 类 号：TG142[一般工业技术—材料科学与工程]