TY - JOUR
T1 - Permeation of niobium through grain boundaries in copper
AU - Sheu, Emmeline
AU - Liu, Tung Yan
AU - Williams, Darrick J.
AU - Baldwin, Jon K.
AU - Demkowicz, Michael J.
PY - 2024/8/1
Y1 - 2024/8/1
N2 - Low mutual solubility is expected to avert interdiffusion in layered composites of phase-separating metals. However, we show that Nb diffuses through polycrystalline Cu—despite the minimal bulk solubility of these elements—due to short circuit transport of Nb along certain grain boundaries in Cu. Atomistic modeling demonstrates that Nb-permeable Cu grain boundaries exhibit negative enthalpy of mixing of Nb, resulting in an enthalpically-stabilized solution of highly mobile Nb atoms that easily diffuse through the boundary. By contrast, Mo, which also has minimal solubility with Cu, has positive enthalpy of mixing at Nb-permeable Cu grain boundaries and does not diffuse through them. Our findings suggest material selection and grain boundary engineering as pathways for designing improved diffusion barriers and thermally stable laminate composites.
AB - Low mutual solubility is expected to avert interdiffusion in layered composites of phase-separating metals. However, we show that Nb diffuses through polycrystalline Cu—despite the minimal bulk solubility of these elements—due to short circuit transport of Nb along certain grain boundaries in Cu. Atomistic modeling demonstrates that Nb-permeable Cu grain boundaries exhibit negative enthalpy of mixing of Nb, resulting in an enthalpically-stabilized solution of highly mobile Nb atoms that easily diffuse through the boundary. By contrast, Mo, which also has minimal solubility with Cu, has positive enthalpy of mixing at Nb-permeable Cu grain boundaries and does not diffuse through them. Our findings suggest material selection and grain boundary engineering as pathways for designing improved diffusion barriers and thermally stable laminate composites.
UR - http://www.scopus.com/inward/record.url?scp=85193620072&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2024.120002
DO - 10.1016/j.actamat.2024.120002
M3 - Article
SN - 1359-6454
VL - 274
JO - Acta Materialia
JF - Acta Materialia
M1 - 120002
ER -