Hydrogen embrittlement has been one of the biggest issues for usage of high-strength structural metals such as steels, Al alloys, Ti alloy and so on. The phenomenon has been figured out through the age, and has not been completely overcome yet. One of the reasons was that there were quite few techniques to detect hydrogen because hydrogen is the lightest and the smallest in the atoms. Recently, the techniques to detect hydrogen has been developed and advanced, and then provided important information on the state, the local position and the local concentration of hydrogen in the metals. This paper aims at the review of the techniques for detecting hydrogen associated with hydrogen embrittlement of the structural metals.
The structure with welded joints made from aluminum- magnesium alloy series 5083 is used without painting on the outdoors. Therefore, corrosion damage management is required for the structure not to suffer localized corrosion during the practical use.
The effect of phosphorous on intergranular corrosion of type 310 stainless steel at transpassive potential was investigated using phosphorous added ultra high purity type 310 stainless steel. Intergranular corrosion depth was measured by scanning electron microscopic observation. Grain boundaries were observed using three dimensional atom probe. Intergranular corrosion was observed on phosphorous added stainless steel. The sample heat treated at 600℃ showed severe integranular corrosion morphology. Observation by three dimensional atom probe revealed that grain boundary with high dissolution rate had segregated zone of chromium and phosphorous about 5nm in width, on the other hand, grain boundary with low dissolution rate had no segregated zone. From these results, it is suggested that intergranular corrosion of phosphorous added type 310 stainless steel at transpassive potential is affected by segregation of phosphorous and chromium along grain boundaries.