For example, in the Beta 21S alloy grain sizes of 40-
50 μm are common (see Fig. 7.2a). The aging treatment (step IV in Fig. 7.1) is
usually done in the temperature region between 500°C and 600°C, i.e. above the
solvus temperature of the metastable coherent particles ω and β' (see Chap. 2,
Sect. 2.8.2).