Crack propagation rate of SCM440H low alloy steel under long term varying load is enhanced by absorbed hydrogen. Substantial acceleration up to 100 times compared with hydrogen free material was observed. The mechanistic role of hydrogen on the acceleration was investigated. (1The crack propagation rate in acceleration stage was approaching 10 times of crack tip opening displacement △CTOD. This acceleration may not be explained by the blunting-resharpening process on the basis of deformation. The predominant fracture mode was quasi cleavage. Hydrogen restrained blunting of crack tip, which resulted in relatively higher stress state in hydrogen-charged material. The higher stress state caused quasi cleavage and hence the acceleration of crack propagation. (2The crack opening displacement (CODwas experimentally measured on hydrogen-charged and uncharged specimens. The stress level for the onset of non-linear behavior in stress-COD relation was higher in hydrogen-charged specimen. These examinations suggested that the mechanistic role of hydrogen is to prevent the blunting of crack tip and bring about higher stress field near the crack tip.
|Publication status||Published - Dec 1 2010|
|Event||18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale, ECF 2010 - Dresden, Germany|
Duration: Aug 30 2010 → Sep 3 2010
|Other||18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale, ECF 2010|
|Period||8/30/10 → 9/3/10|
All Science Journal Classification (ASJC) codes
- Mechanics of Materials