Publication Date
9-18-2018
Department
Ames Laboratory
Campus Units
Ames Laboratory
OSTI ID+
1477199
Report Number
IS-J 9767
DOI
10.1088/1361-651X/aadea3
Journal Title
Modelling and Simulation in Materials Science and Engineering
Volume Number
26
Issue Number
7
First Page
075004
Abstract
An Ag–Ni semi-empirical potential was developed to simulate the segregation of Ni solutes at Ag grain boundaries (GBs). The potential combines a new Ag potential fitted to correctly reproduce the stable and unstable stacking fault energies in this metal and the existing Ni potential from Mendelev et al (2012 Phil. Mag. 92 4454–69). The Ag–Ni cross potential functions were fitted to ab initio data on the liquid structure of the Ag80Ni20 alloy to properly incorporate the Ag–Ni interaction at small atomic separations, and to the Ni segregation energies at different sites within a high-energy Σ9 (221) symmetric tilt GB. By deploying this potential with hybrid Monte Carlo/molecular dynamics simulations, it was found that heterogeneous segregation and clustering of Ni atoms at GBs and twin boundary defects occur at low Ni concentrations, 1 and 2 at%. This behavior is profoundly different from the homogeneous interfacial dispersion generally observed for the Cu segregation in Ag. A GB transformation to amorphous intergranular films was found to prevail at higher Ni concentrations (10 at%). The developed potential opens new opportunities for studying the selective segregation behavior of Ni solutes in interface-hardened Ag metals and its effect on plasticity.
DOE Contract Number(s)
AC02-05CH11231; AC02-07CH11358; SC0016270
Language
en
Department of Energy Subject Categories
36 MATERIALS SCIENCE
Publisher
Iowa State University Digital Repository, Ames IA (United States)
