Grain-boundary engineering markedly reduces susceptibility to intergranular hydrogen embrittlement in metallic materials
✍ Scribed by S. Bechtle; M. Kumar; B.P. Somerday; M.E. Launey; R.O. Ritchie
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 796 KB
- Volume
- 57
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
The feasibility of using ''grain-boundary engineering" techniques to reduce the susceptibility of a metallic material to intergranular embrittlement in the presence of hydrogen is examined. Using thermomechanical processing, the fraction of ''special" grain boundaries was increased from 46% to 75% (by length) in commercially pure nickel samples. In the presence of hydrogen concentrations between 1200 and 3400 appm, the high special fraction microstructure showed almost double the tensile ductility; also, the proportion of intergranular fracture was significantly lower and the J c fracture toughness values were some 20-30% higher in comparison with the low special fraction microstructure. We attribute the reduction in the severity of hydrogen-induced intergranular embrittlement to the higher fraction of special grain boundaries, where the degree of hydrogen segregation at these boundaries is reduced.