4. Main limiting factors for properties

One of the most common assertions made by the scientific community about TiAl is that these alloys are not sufficiently reliable due to the wide dispersion of their mechanical properties. Industrialists are therefore keen to identify the causes of property dispersion in these alloys, so that the results obtained on one batch of alloys can be transposed to another batch of alloys, and then to actual parts to meet their specifications.

Given the diversity of data sources concerning properties in use, it is not surprising to find a certain dispersion in mechanical test results. This disparity, attributed somewhat hastily to a lack of knowledge of certain factors specific to the various laboratories, can in fact be quantified or even reduced: the precise composition with levels of impurities, the metallurgical state which conditions a number of parameters (grain size,...