Environment-assisted cracking of iron aluminide in 3.5% NaCl solution
- Univ. of Calgary, Alberta (Canada). Dept. of Mechanical Engineering
In 3.5% NaCl solution, the environment-assisted cracking behavior of an iron aluminide alloy was studied. Slow strain rate tests were done at different electrochemical potentials. A 55% loss in ductility was found when tested at anodic potentials, which suggests a material degradation by the aqueous environment. Results of the experiments that were carried out using pre-immersed specimens and notched tensile specimens confirmed this material degradation to be stress corrosion cracking (SCC). To identify the mechanism, an electrochemical permeation technique was employed. By measuring the diffusible hydrogen concentration, sensitivity to hydrogen embrittlement has been assessed at different potentials. Fracture surfaces were examined under the scanning electron microscope (SEM). Fracture mode was found to be mainly transgranular quasi-cleavage, except the ones tested at anodic potentials (that are 0 mV and {minus}100 mV vs SCE) on which intergranular SCC was found near the edge. It is believed that these cracks were initiated from the pits. These results indicate that the environment-assisted cracking is an intergranular SCC, controlled by anodic dissolution mechanism.
- OSTI ID:
- 215374
- Journal Information:
- Scripta Materialia, Vol. 34, Issue 6; Other Information: PBD: 15 Mar 1996
- Country of Publication:
- United States
- Language:
- English
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