Introduction

Objective

Atomic (View) of the mechanism

Effect of solute (Ni) concentration 

on GB displacement

Driving force for DIGM

Effect of solute segregation on 

GB displacement

Conclusions

This presentation poster was designed by FPPT.

Model Approach

 To simulate grain boundary migration induced by diffusion by using Molecular 

Dynamic Simulations.

 The present study is focused on DIGM when solute sink is present.

Segregated solute atoms 

0 ns

Grain 1

Grain 2

Grain Boundary

Al atoms

Ni atoms

4 ns

 When concentration of solute atoms fall below equilibrium due to solute depletion, 

GB moves toward solute atoms trying to regain equilibrium and creating a 

dealloyed zone in its wake.

Driving force needed to move GB increases with increasing conc. of 

solute atoms.

 It is observed that when solute sink is present, depletion of GB solute

content to below the equilibrium level (due to diffusion of solute from GB

to sink), causes the boundary to move through high solute field to regain

equilibrium thereby creating de-alloyed zone.

 Part 1. GB migration is driven by the need to reduce total energy of the

system which is achieved by solute segregation.

 Part 2.This is dynamic process, continuing until the boundary has returned

to its stabilized position and stops when equilibrium is regained.

 Segregation plays a crucial role in promoting DIGM.

Grain Boundary (GB) displacement 

in Al bicrystal models

Part1

Part2

0 1 2 3 4

-209600

-209580

-209560

-209540

-209520

-209500

-209480

-209460

-209440

-209420

Tot Energy (eV)

Time (ns)

Energy decrease as solute atoms are 

segregated to GB

Minimum energy configuration (stabilization) 

achieved by solute segregation at GB

Part1

GB is moving toward 

Part2

solute atoms

Part1

Part2

GB stops moving

Solute segregation increases 

as GB moves initially to regain 

equilibrium

Maximum solute segregation 

resulting in equilibrium 

0 ns

0.2 ns

0.6 ns

1 ns

Grain 1

Grain 2

Grain 

Boundar

y

Al atoms

Ni atoms

4 ns

Dealloyd

zone 

0 1 2 3 4

-14

-12

-10

-8

-6

-4

-2

0

2

GB Displacement (Å)

Time (ns)

GB displacement increases with increase in solute concentration.

 Solute segregation increases as the grain boundary moves with time.

 No. of segregates solute atoms also increase with increasing 

concentration of solute atoms in grain 2 of Al bicrystal.

Diffusion-induced grain boundary motion (DIGM) can be caused when

solute atoms diffused out of grain boundary (GB) in the presence of solute sink or

diffuse into the GB in the presence of solute source thereby causing the boundary to

migrate and produce de-alloyed (solute depleted) and alloyed zones (solute

enriched).

Acknowledgement

The financial support from Natural Sciences and Engineering Research Council of 

Canada (NSERC) is gratefully acknowledged.

Technological Applications

 Surface Alloying

 Improving creep resistance

 DIGM can reduce fatigue lifetimes.

 DIGM can cause premature failure in electrical interconnects.

To control DIGM, operating driving forces and mechanisms 

needs to be understood

Motivation

Atomistic Simulations of Diffusion Induced Grain Boundary Migration in Aluminium

Navjot Kaur, Chuang Deng* and Olanrewaju. A. Ojo*

Department of Mechanical Engineering, University of Manitoba, Winnipeg, Canada R3T 5V6

Assumption: It is assumed that solute sink is present which depleted GB 

from solute atoms.