Abstract
Microbes affect the degradation process in many ways, the relationship between microstructure and microbial interaction has often been overlooked. This is particularly true in welded structures, where the microstructure of the fusion zone and heat affected zone can create environments that support microbial metabolism. This paper will present the results of several investigations involving stainless steels, aluminum alloys, and low alloy steels. It will also address the affect of welding on MIC susceptibility in these materials. It is not meant to be a review of MIC study in general, nor is it an extensive review of a particular facet of MIC research - it is a review of MIC work accomplished by researchers in our laboratory and associated laboratories - with a focus on the relationship between metallurgical microstructure and MIC. Microbes seem to accelerate the corrosion process - locating susceptible areas, fixing anodic sites, and producing or accumulating chemical species that promote corrosion. Alloy composition and microstructure play a crucial role in the corrosion process, but surface geometry and thermomechanical history are also critical.
