Evolution of nanoscale clusters in γ′ precipitates of a Ni–Al–Ti model alloy

The origin and stability of nanostructural hierarchy in crystalline solids

“…A typical g-g′ microstructure consists of ordered g′ precipitates in a continuous, disordered g matrix. Variations in this structure are occasionally observed, however, such as an inverted microstructure in which g precipitates reside in a continuous g′ phase (9)(10)(11)(12) as well as a hierarchical microstructure consisting of a g matrix with g′ precipitates embedded with still finer-scale g particles (4,(13)(14)(15), as shown in Fig. 1.…”

“…For hierarchical microstructures, delayed coarsening of the encompassing g′ precipitates has been reported during the time in which the embedded nanoscale g precipitates enlarge (4,13). In these relatively high lattice misfit hierarchical superalloys, the tiny g precipitates coarsen into raft-like structures that eventually reach the edges of the encompassing g′ precipitates and subdivide the larger cuboidal g′ precipitates (4,14,15). This chemical phase separation of the individual larger-sized g′ precipitates ultimately results in the splitting of g′ precipitates with continued high-temperature exposure.…”

Analysis of Phase Transformations in Fe-Ni-Al Alloys Using Diffusion Couples of Fe/Fe-33at.%Ni-33at.%Al Alloy/Ni

“…These precipitates also coarsen with aging time and show a preferential alignment in the β matrix. It is important to mention that this inverse precipitation is not as common as the inverse precipitation γ →γ + γ reported [65,66] in Ni-base superalloys. This precipitation is also promoted with higher contents of Ni and Al.…”

“…This phase commonly appears during the precipitation of Ni-based superalloy. The γ′ phase also provides the creep strength for operation at high temperatures [1,65,66]. The interface between the γ′ precipitate and the γ matrix phase is coherent, which is related to their excellent creep strength and coarsening resistance at high temperatures.…”

Hierarchical microstructure strengthening in a single crystal high entropy superalloy

“…In a previous work on Ni 86.1 Al 8.5 Ti 5.4 alloy 44,51,52 , the FCC particles could coarsen into directional plates in the L1 2 matrix after prolonged ageing at 1,023 K. Meher et al 45 also found that ageing at 1,073 K could coarsen www.nature.com/scientificreports/ the FCC particles and decreased its fraction significantly. In this work, since the FCC particles in the L1 2 phase were in metastable states, all the FCC particle forming elements would diffuse across the L1 2 phase into the surrounding FCC matrix after prolonged ageing, so that the whole system could reach the equilibrium state, Fig.…”