【摘要】 采用正电子湮没寿命谱(PALS)和符合多普勒展宽谱(CDB)等方法研究了AISI304不锈钢中氢与缺陷的相互作用。PALS实验结果表明:氢致缺陷尺寸随充氢电流密度的增大而变大,缺陷数量随充氢电流密度的增大而增多。进一步地,通过比较CDB实验的商谱曲线,发现在电解充氢后,高动量区出现了明显的峰,且峰位不随充氢条件改变;这表明氢可能会与空位发生相互作用,氢进入样品内部以后,可以作为聚集空位的核心而形成空位团,即形成氢与缺陷的复合体,导致缺陷化学环境的变化。更多还原

【Abstract】 Interaction between hydrogen and defects in AISI 304 stainless steel was investigated by positron annihi- lation lifetime and coincidence Doppler broadening (CDB) measurements. Hydrogen was electrochemically charged into the annealed stainless steel samples in 0.5 mol/L H2SO4 solution for 1h at different current density. Experimental results show that mean lifetime τ, second lifetime component τ2 and its intensity I2 increase with current density. This means that hydrogen-induced defects are created in the annealed stainless steel samples. Furthermore, the CDB ratio curves (ratio to annealed sample) show that the enhancement in the low-momentum region (less than 5×10-3 m0c) af- ter hydrogen-charging denotes that the positrons are trapped in hydrogen-induced defects, which is consistent with the result of positron lifetime. It is interestingly found that an obvious peak appears in the high-momentum region after hydrogen-charging, and the peak site doesn’t vary with current density. This suggests that hydrogen might interact with vacancy and become the center of vacancy accumulation, leading to the formation of vacancy-hydrogen com- plexes, which results in the change of chemical environment of defects.更多还原