用高温显微镜原位观察钢中氢腐蚀裂纹愈合过程  

IN-SITU INVESTIGATION OF HEALING ON HYDROGEN-ATTACKED CRACK IN STEEL BY HIGH-TEMPERATURE MICROSCOPE

作　　者：董超芳[1] 徐璟[1] 李晓刚[1,2] 褚武扬[1] 

机构地区：[1]北京科技大学材料科学与工程学院 [2]中国科学院金属研究所金属腐蚀与防护国家重点实验室沈阳110016

出　　处：《中国腐蚀与防护学报》2003年第3期179-182,共4页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金项目 ( 5 99710 11); 973"材料的环境行为与失效机理"项目共同资助

摘　　要：利用高温显微镜 ,对碳钢氢腐蚀裂纹的愈合过程进行原位、实时观察 ,通过录象记录了整个裂纹愈合实验过程 .结果表明 ,裂纹在加热到 6 30℃左右时 ,发生明显愈合而变小变细 .实验中造成的CH4气体散失和内部裂纹表面化使得实验结果与真实情况有一定的偏差 ,观察得到裂纹闭合的临界温度 6 30℃低于实际裂纹闭合温度 .发生氢蚀裂纹愈合的机制是热扩散 ,动力是氢蚀气泡长大导致的塑性变形能Es.在Fe、C和H原子扩散足够快的情况下 ,氢蚀裂纹愈合的条件是Es 大于 2γ/r(γ为界面表面张力 ,r为气泡半径或裂纹半长 ) .The in-situ observation of hydrogen-attacked cracks healing in carbon steel had been done by high-temperature microscope.The whole cracks healing process was recorded at the same time.The results show that the cracks became obviously thinner when heated under 630℃.The escaping of methane and inner crack exposure on specimen surface make a certain difference between this experiment and true condition,the analysis indicates the cracks healing temperature in experiment is lower than actual system.The healing of hydrogen attacked cracks is closely related to heat diffusion of Fe and C atoms in steel.The driving force of crack healing results from the plastic deforming energy E s induced by the growth of hydrogen attacked bubbles or cracks.The critical condition of healing of bubbles or cracks is E s ≥2 γ/r (where γ is the surface tension, r is the radius of bubbles or half length of crack).

关 键 词：高温显微镜 原位 氢腐蚀 裂纹 愈合 

分 类 号：TG111.91[金属学及工艺—物理冶金] TG142.71[金属学及工艺—金属学]