EFFECTS OF HYDROGEN ATOMS OF INITIATION AND PROPAGATION OF CRACKS UNDER SLOW LOADING
慢加载条件下氢对裂纹萌生与扩展的作用

The effects of hydrogen atoms on crack initiation and propagation have been studied in normalized Cr-1Mo steel using in situ SEM tensile experiment. The results are found that the critical plastic deformation at notch root for initiation of ductile crack is reduced by charging hydrogen, and the crack propagation pattern is also changed from continuous growth on the plane of maximum shear stress to uncontinuous growth on maximum normal stress plane. Hydrogen induced plastic deformation has not been found, and the effect mechanisms of hydrogen atoms are analysized.