.png){kind=icon}
.png){kind=icon}
Return
Construction of thermal-stability maps for nanocrystalline metals and alloys with U-shaped dependence of stability on grain size
.png){kind=icon}
PRE
AI
H
W
DOI：10.1016/j.actamat.2026.122329.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Nanocrystalline metals and alloys are attractive for a wide range of applications, but their broader use is often limited by poor thermal stability. Classical curvature-driven grain-growth theory predicts progressively faster coarsening with decreasing grain size. However, recent experiments across face-centered cubic (FCC) metals and alloys have revealed a non-monotonic stability trend: the thermal-stability-limit temperature—defined as the temperature at which grain growth rapidly accelerates for a fixed exposure time—first decreases with grain refinement in the microscale regime but increases again in the nanoscale regime, producing a U-shaped stability response. In this work, we extend the classical grain-growth law by incorporating junction-mediated kinetic resistance, with coherent twin boundary (CTB)-mediated triple-junction drag identified as a key contribution. The dimensionless drag parameter is formulated from mechanistically motivated mobility contrasts, CTB density, and size-dependent junction statistics. A single calibration constant is determined from pure Cu and then held fixed across other materials to test transferability. Time-resolved mean-field simulations—using temperature-dependent parameters and purity-dependent diffusivities—reproduce the U-shaped stability behavior across FCC systems and further enable construction of time-temperature thermal-stability maps. These maps can be used to guide grain-size selection and define practical service windows for property-targeted microstructure design.
Keywords:
nanocrystalline metals
thermal stability
grain growth
U-shaped stability
triple-junction drag
Journal
IF:
9.3
Papers:
2.0W
Citations:
12.9W
Organization
No organization information available
Cited Papers