Iron aluminide intermetallic alloys are a promising low cost and resource insensitive family of materials which are suffering from severe hydrogen embrittlement (HE) sensitivity. Alloying of this intermetallics with a third element can improve their resistance against HE. However, conventional mechanical testing methods for characterization and quantitative evaluation of the resistance against HE are very costly and time consuming.With the in situ electrochemical nanoindentation method developed in our institute, it is possible to quantitatively evaluate the sensitivity of metals to HE by measuring the reduction in the activation energy for dislocation nucleation due to hydrogen. Samples required to perform these tests are of a few cubic millimeter in size and it is possible to perform many indentations on a single sample. Such a small sample can be heat treated to produce different ordered crystal structures and again be tested for sensitivity to HE. Hence, the effect of the crystal structure, different dislocation types and vacancy concentration in combination with the third alloying elements can be thoroughly examined.
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