Document Type
Paper
Abstract
Experimentation to study stress corrosion cracking (SCC) often requires simulation of aggressive environments that include both tensile loading with simultaneous chemical exposure. This demands complex testing approaches that will benefit from multi-mode measurements to capture in-situ degradation. Multi-mode measurements aid in characterizing the nature of the reaction, quantifying the formation of corrosive products and in calculating the breakdown potential of the sample. This paper details a testing approach for the chemical aspect of SCC on aluminum samples where sample and experimental design facilitates in-situ imaging. In initial tests, 3.5 wt. % NaCl solution is applied to AA7075 for specific time frames which initiate the pitting process. The testing approach enables to produce optical microscope images of real-time reactions. Raman and microscopy measurements help capturing failure initiation mechanisms which eventually lead to crack propagation. Identification of specific Raman peaks reveals the nature of the products formed on the surface using the pre-exposure values as a baseline for the characterization. These results from multi-mode measurements can be compared to understand SCC processes with both qualitative and quantitative information. Knowledge gained can be used to design materials and processes to better withstand corrosive environments.
Development of a Stress Corrosion Cracking test approach for multi-mode measurements
Experimentation to study stress corrosion cracking (SCC) often requires simulation of aggressive environments that include both tensile loading with simultaneous chemical exposure. This demands complex testing approaches that will benefit from multi-mode measurements to capture in-situ degradation. Multi-mode measurements aid in characterizing the nature of the reaction, quantifying the formation of corrosive products and in calculating the breakdown potential of the sample. This paper details a testing approach for the chemical aspect of SCC on aluminum samples where sample and experimental design facilitates in-situ imaging. In initial tests, 3.5 wt. % NaCl solution is applied to AA7075 for specific time frames which initiate the pitting process. The testing approach enables to produce optical microscope images of real-time reactions. Raman and microscopy measurements help capturing failure initiation mechanisms which eventually lead to crack propagation. Identification of specific Raman peaks reveals the nature of the products formed on the surface using the pre-exposure values as a baseline for the characterization. These results from multi-mode measurements can be compared to understand SCC processes with both qualitative and quantitative information. Knowledge gained can be used to design materials and processes to better withstand corrosive environments.
