Analyzing Engineering Materials - Assignment Example

The figure below shows an aluminum component that is threaded into another component of aluminum, with crevice corrosion observable on threads. The resultant of this would be the loss of threads and finally loosening of the components.

The mechanism behind this corrosion is in the difference that occurs in levels of oxygen between the internal crevice and the external surface. The depletion of oxygen on the crevice causes it to be the anode creating an extremely corrosive environment inside the crevice. The corrosion occurs on the low-oxygen area acting as the anode with protection on the high oxygen area as the cathodes.

Pitting is another form of localized corrosion that penetrates metals as quickly as possible mostly at an angle of ninety degrees. As a result of it, we can have leaking tanks. This kind of corrosion is often hard to identify. The moment it is visible to humans, the damage will have been extended the passivation layer of stainless steel makes it vulnerable to pitting corrosion rather than uniform corrosion. The figure below shows pits on stainless steel rings after it was subjected to the marine environment.

Surface corrosion occurs on the surfaces of the materials in question.it has different types that include: stainless steel involves a flat-gray uniform surface attack mostly leading to significant damages in form of deposits of corrosion. Non-stainless products do suffer extreme corrosion under a pale-black surface. Color-anodized surfaces involve crater formation in places of heavy attacks. In normal conditions, only a partial or complete loss of color intensity occurs. This kind of corrosion occurs as a result of chemical and electrochemical influences. This only happens when there is a connection with excessive acid contents about stainless steel, soldered connections, and sintered carbide metal are concerned. In the case of stainless steel, corrosion is aided by the impact of water/humidity. On anodized surfaces, the impact of acids or alkaline agents is key.

De-aerated (no oxygen) acid can be referred to as a relatively reducing environment. The oxidizing power of the de-aerated acid is enough to cause corrosion on both magnesium and iron but not copper or gold. Dehydrated hydrochloric acid is a good example of a highly reducing environment. The corrosiveness of an environment is highly reliable on the degree of ionization of the chemical species present in the solution.

Beach marks are concentric loops that are found in the fatigue region resembling tide marks on the sea beach. They are responsible for the indication of all the arrest points that occurred as the crack advanced. The beach marks are always facing vertical about the direction of the applied stress. An analysis of the failure shows how the failed part was loaded and the exact point where cracking started. Ratchet marks are represented by steps present on the outer diameter of the fracture. They represent a fatigue fracture that was started on numerous locations of the material. The progression of these multiple fatigue cracks in the material results in a singular joint single fracture plane. The size of the final fractured area indicates the presence of extreme levels of stress applied on the surface of the material. The stress might have been applied to the same location or within the same proximity.