Mise en evidence par diffraction et par microscopie electroniques de la decomposition spinodale d'un alliage nickel-manganese non stoechiometrique

Order-Disorder Transitions in Substitutional Solid Solutions

“…8) due to the migration of a grain boundary during ordering. According to [46], this migration is due in the Ni-Mn system to a difference of composition, and thus of chemical potential, in contiguous grains caused by ordering through nucleation and growth in a two-phase (L1, + Ll,) domain of the phase diagram. The local variation of composition inside a single grain may give rise to a steep variation of the size of the antiphase domains [46] and to a complicated morphology of the thermal APBs ( Fig.…”

“…l 8. 100 superlattice dark field of columnar antiphase domains produced in Ni-33.6 ato/k Mn by the migration of a grain boundary during annealing a t 400 "C [46] mentioned by Marcinkowski [53] and it has recently been thoroughly reviewed by Amelinckx [54] so that we shall not go into details here. Let us just recall that transmission electron microscopy (and particularly the weak-beam technique) enables us to estimate the energy of the APBs (e.g.…”

“…Complicated morphology of thermal APBs due to grain boundary migration and composition variation in Ni-33.6 atyo Mn[46] …”

Precipitation Behavior in Fe–Mn–Cu Austenitic Alloys

“…In the case of the two-phase decomposition, there are two mechanisms. Namely, (1) nucleation and growth and (2) spinodal decomposition(1)- (8). Especially, in spinodal decomposition the decomposed phase which has a good coherency with the matrix is formed rapidly and grows slowly during aging.…”

Étude des phénomènes prémonitoires des transitions de phases dans les alliages, par microscopie et diffraction électroniques

“…[{ 110 }* diffraction pattern in Al-62.5 at % Ni [40]. a) Diffuse intensity due to short-range ordering of nickel antistructure atoms ; b) long-range order reflections of the superstructure Ni2Al ; c) indexation of figure 3b ; d [56], [57] et des alliages (Cu-Mn)3AI en les phases L21 et D03 (58) (Fig. 4).…”