Abstract: In this article, different techniques to test notched small punch test samples in fracture conditions in aggressive environments are studied, based on the comparison of the micromechanisms at different rates. Pre-embrittled samples subsequently tested in air at rates conventionally employed (0.01 and 0.002?mm/s) are compared to embrittled ones tested in environment at the same rates (0.01 and 0.002?mm/s) and at a very slow rate (5E?5?mm/s). A set of samples tested in environment under a set of constant loads that produce very slow rates completes the experimental results. As a conclusion, it is recommended to test small punch test notched specimens in environment at very slow rates, of around E?6?mm/s, when characterizing in hydrogen embrittlement scenarios, in order to allow the material?environment interaction to govern the process.

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