A method of examining a titanium alloy with an alpha phase and a beta phase is disclosed. The method includes: cutting a sample of a part made of the alloy; preparing a region of the cut surface of the sample situated in the vicinity of the edge of the sample, the edge being in common with the outside surface of the part; observing the alpha phase of the region at a magnification of greater than ×5000; deciding on whether granularity is present or absent in the alpha phase of a first zone contiguous with the edge of the sample; and concluding that the alloy has been contaminated with a gas if granularity is found to be absent in the alpha phase of the contiguous zone whereas granularity is present in the alpha phase outside the contiguous zone.