Figure 4. Radius distributions of Cu precipitates in the three alloys after aging for 20 and 60 min, with insets showing the 10 at.% Cu isosurfaces, together with the proxigram analysis of the Cu precipitates in (A-C) Cu-0Mn steel, (D-F) Cu-4Mn steel, and (G-I) CuNiAl-4Mn steel.