Encyclopedie de la recherche sur l'aluminium au Quebec - Edition 2014 | Page 52

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TRANSFORMATION ET APPLICATIONS // TRANSFORMATION AND APPLICATIONS

Lorentz Force Utilized in
Ex-Situ Synthesis of
L'UTILISATION DE LA FORCE DE DE LORENTZ DANS LA SYNTHÈSE Al-TiB2
EX-SITU DES NANOCOMPOSANTES Al-TiB Nanocomposites
2

(L’utilisation de la force de Lorentz dans la
UTILIZING THE LORENTZ FORCE IN EX-SITU SYNTHESIS OF Al-TiB2 NANOCOMPOSITES
synthèse Ex-Situ des nanocomposites
Al-TiB2)
A.M. Nabawy, X.-G. Chen
NSERC/Rio Tinto Alcan Industrial Research Chair
in Metallurgy of Aluminum Transformation, UQAC
.

Metal matrix nanocomposites combined the outstanding
metallic and ceramic properties leading to superior
performance at elevated and room temperatures. Synthesising
of MMNC is associated by significant challenges such as poor
wettability, oxidation of melt, and clustering tendency of nano
particles. Those challenges are addressed in the present study
by devolving a novel melt processing technique of Al-TiB2
nanocomposite. In this technique the Lorentz stirring force
was employed to enabling full wetting and incorporation of
nano TiB2 particles to aluminum melt. Modern imaging
techniques of scanning electron microscope (SEM) and
transmission electron microscope (TEM) were conducted for
the microstructural characterization. Results denoted that the
Lorentz stirring force enabled full wetting and incorporation of
nano-TiB2 particles to aluminum matrix. The 20wt%TiB2
addition provide a significant strength improvement.

Develop a practical
processing technique of
nanocomposite material
Optimize the distribution of
nano-ceramic reinforcements

Compaction

Ultrasonic Mixing
TiB2

Al

Compacted
Mixture@400MPa
Mixture

Enhance the elevated temperature
properties

Melt Processing

Degassing By Argon

Induction Melting

Testing
FESEM Image

TEM Image

FESEM

TEM

Micro-Hardness

TiB2

Lorentz
Stirring Force

Shearing Forces

Clustering
Breaking Down

Shearing Forces

100HZ

Shearing Forces

Sever liquid shearing leads to
clustering breaking down
180KHZ

Ahmed M. Nabawy
X.-Grant Chen
Chaire industrielle
de recherche
CRSNG/Rio Tinto Alcan
sur les nouvelles avenues en
métallurgie de la
transformation de l’aluminium
(CIMTAL),
Université du Québec
à Chicoutimi

Although elevated frequency results in skinning of Lorentz force at
boundary, the Lorentz force displayed extremely high levels.

Hardness Value (HV)

100
90
80
70

1. Ex-situ synthesis of Al-TiB2 nanocomposite was employed
successfully under stirring effect of Lorentz force.

60
50

40
30

Pure Al

850C-3C/s 850C-6C/s 950C-3C/s 950C-6C/s

Processing Conditions

Microstructure evolution of Al-20wt%TiB2 nanocomposite
processed at 850oC and two heating rates 3oC/s and 6oC/s.

Micro-hardness measurements of Al-TiB2
nanocomposite.

Processing conditions of lower melting temp. and heating rate displayed
the highest strength and uniform distribution.

2. Lorentz stirring force displayed a high capacity in enabling prefect
wetting and incorporation of nano TiB2 particles into the melt.
3. Microstructure analysis indicated that TiB2 distributed uniformly
within the grains and clustering at inter-dendritic regions.
4. The addition of 20%TiB2 improved the hardness level of
aluminum matrix by more 100%.
5. Lower melting temperature and heating rate provided the best AlTiB2 castings.

Journée desnovel melt processing technique of an Al-TiB
A étudiants – REGAL

Une nouvelle technique de traitement de fonte du nanocomposite d'Al-TiB2 a été
développée en utilisant la force d’agitation de Lorentz. Une unité de fusion par
induction à haute fréquence a été utilisée pour fabriquer un alliage d’aluminium
nanocomposite contenant 20 % en poids de TiB2 à différents paramètres de
traitement à l'état fondu. Une étude a été faite sur l'effet des paramètres de
traitement, tels que la température de fusion et le taux de chauffage sur les
propriétés microstructurales et mécaniques d'un nanocomposite d’Al avec 20 
%
en poids de TiB2. Les techniques modernes d'imagerie au microscope électronique
à balayage (MEB) et en microscopie électronique à transmission (TEM) ont
été exploitées pour la caractérisation de la microstructure. Les résultats ont
démontré que la force d'agitation de Lorentz a activé