About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
2026 Graduate Student Poster Contest
|
| Presentation Title |
SPG-6: Model-Driven Sequential Heat Treatment of LPBF Cu-Cu-30Ni-1Nb: Decoupling Recrystallization and Ageing for Strength-Ductility Synergy |
| Author(s) |
Debasis Rath, Markus Chmielus, Zachary Harris |
| On-Site Speaker (Planned) |
Debasis Rath |
| Abstract Scope |
Cu-30Ni-1Nb fabricated via LPBF solidifies into columnar grains with a high geometrically necessary dislocation (GND) density and a nanoscale niobium oxide dispersion decorating the cell walls. Subsequent solution treatment reveals a sharp kinetic cliff in which recrystallization remains strongly suppressed for hours, then completes abruptly near 1075°C, yet the higher temperatures that accelerate it simultaneously trigger abnormal grain growth that reduces the yield strength. The governing mechanisms are resolved through a coupled experimental and modeling approach leveraging CALPHAD, high resolution EBSD, and Transmission Electron Microscopy (TEM), mapping the stored energy driving recrystallization against the temperature-dependent Zener pinning efficacy. Results reveal that the kinetically retained niobium oxide supplies this pinning and that abnormal growth is dictated not by the mean driving pressure but by the rate and spatial heterogeneity of pinning loss. This competition between boundary migration and pinning release defines the narrow window yielding a fine, equiaxed, recrystallized microstructure. |