1.1 This practice covers the assignment of designations for all alloy phases, based on the composition and crystal structure of each.

1.2 The practice makes possible the selection of a unique designation for each phase, except that in some cases an arbitrary lower case letter is used as described in 3.4 and 3.5.

1.3 The same designation shall be used for a given phase regardless of the system in which it appears (single component, binary, ternary, or polynary).

1.4 A procedure for selecting a temporary designation is also provided to cover those cases in which not enough information is available to assign the permanent designation.