Characterization of the high temperature fracture of He-implanted 1.4970 austenitic stainless steel
Characterization of the high temperature fracture of He-implanted 1.4970 austenitic stainless steel
The Ti-stabilized DIN 1.4970 austenitic stainless steel is an important candidate for high temperature - high neutron fluence applications which will create appreciable amounts of He within the matrix. In order to determine the mechanical effects associatedwith the presence of He alone a set of tens...
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Personal Name(s): | Sagües, A. A. (Corresponding author) |
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Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Kernforschungsanlage Jülich, Verlag
1977
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Physical Description: |
56 p. |
Document Type: |
Report Book |
Research Program: |
ohne Topic |
Series Title: |
Berichte der Kernforschungsanlage Jülich
1409 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
The Ti-stabilized DIN 1.4970 austenitic stainless steel is an important candidate for high temperature - high neutron fluence applications which will create appreciable amounts of He within the matrix. In order to determine the mechanical effects associatedwith the presence of He alone a set of tensile specimens was cyclotron implanted to uniform He concentrations in the 10$^{-6}$ to 10$^{-4}$/at. range and later creep tested at 700 and 800 °C. It was found that the elongation to fracture value of the implantedspecimens were reduced with respect to those of unimplanted controls. Scanning electron microscope examination evealed that fracture starts as intergranular and subsequently propagates in a transgranular fashion, the intergranular part being much more extended in the implanted material. Cavities appearing in the fractured grain boundaries of the implanted specimens were associated with grain boundary chromium carbide precipitates. Transmission electron micrsocope examination of the creep specimens and of foils annealed at temperatures between 800 and 1000° C after implantation revealed that He segregated as bubbles in the matrix, at the grain boundaries and at intergranular precipitates. A mechanism of He induced cavitation is discussed which accounts for the observed loss of ductility. Changes in the mode of crack propagation during fracture are attributed to geometrical factors and tensile loading characteristics. |