The invention relates to a method for testing the crystallographic orientation of at least one grain of a turbomachine part, comprising the steps of: a) emitting a beam of electromagnetic radiation through an elementary volume of the part and recording diffraction information on the electromagnetic radiation through the part; b) repeating step a) on a given area of the part, c) determining the crystalline spatial orientation of each of said elementary volumes and deducing therefrom the presence of at least one first crystallographic grain for which the elementary volumes are oriented according to the same crystallographic orientation; d) calculating the angular distance between the crystalline spatial orientation of said first grain and a predetermined direction taken from the part and comparing it to a first predetermined threshold value; e) determining a state of use of the part.
