Effects of stacking fault energy and ordering energy on grain boundary character distribution of recrystallized L12-type ordered alloys

Microstructural feature of the recrystallized Co-based (Co3Ti) and Ni-based (Ni3(Si,Ti) and Ni3Fe) ordered alloys with L12 structure was investigated by the electron backscatter diffraction (EBSD) method with emphasis on grain boundary character distribution (GBCD). For comparison, the GBCDs of the recrystallized Co-Ni, Ni-Fe and 70/30 brass disordered alloys, and also copper, nickel and aluminum pure metals with A1 (fcc) structure, which have widely different stacking fault energies, were also determined. The frequency of Σ3 boundary for the Co-based alloys is higher than that for the Ni-based alloys, regardless of ordered L12 alloy or disordered fcc alloy, indicating that the frequency of Σ3 boundary is primarily dominated by stacking fault energy. Furthermore, the effect of ordering energy on microstructure and energy of the grain boundaries, including Σ3 boundary in the ordered L12 alloys is discussed.