ENCYCLOPÉDIE DE LA RECHERCHE SUR L’ALUMINIUM AU QUÉBEC 2013 | Page 47

NOUVEAUX PRODUITS ET MATÉRIAUX À BASE D'ALUMINIUM
NEW ALUMINIUM BASED PRODUCTS AND MATERIALS
Prediction of elevated temperature flow behavior of 1xxx
alloys with various iron and silicon levels
LA PRÉDICTION DU COMPORTEMENT D'ÉCOULEMENT À TEMPÉRATURE ÉLEVÉE
La prédictionDES comportement À DIFFÉRENTES TENEURS EN FER ET EN SILICIUM
du ALLIAGES 1XXX d'écoulement à

45

température élevée des alliages 1xxx àBEHAVIOR AT HIGH TEMPERATURE OF 1XXX
PREDICTION OF FLOW différentes
teneurs en fer WITH silicium
ALLOYS et en DIFFERENT IRON AND SILICON CONCENTRATIONS
Mohammad Shakiba, X.-Grant Chen
NSERC/Rio Tinto Alcan Industrial Research Chair
in Metallurgy of Aluminum Transformation, UQAC

Introduction

objectives

Commercially pure aluminum exhibits higher strength and work hardening compare to high
purity aluminum. Fe and Si play main role on strength and work hardening of 1xxx alloys
and the contribution from the other trace impurities is negligible. Therefore, analysis the
effect of iron and silicon on hot deformation behavior is the primary concern in this regard.
Furthermore, finding a way to predict deformation behavior at various Fe and Si levels could
be very helpful for designer of forming processes and permit significant reductions in the
design cost.

Studying the hot deformation behavior of 1xxx
alloys with systematic variation on the Fe (0.10.7) and Si (0.1-0.25) contents.
 Developing constitutive equations correlating
flow stress, deformation temperature and strain
rate considering compensation of chemical
composition.

Experimental

Alloys composition
Alloy
Al-0.1Fe-0.1Si

Fe
0.12

Si
0.10

Casting

Fe/Si

Uniaxial hot compression test

Homogenization

Temperature
(oK)

1.20

Strain rate
(s-1)

Al-0.3Fe-0.1Si

0.28

0.10

2.80

623

0.01

Al-0.5Fe-0.1Si

0.49

0.10

4.90

Al-0.7Fe-0.1Si

0.68

0.11

6.18

673

0.1

Al-0.1Fe-0.25Si

0.13

0.24

0.30

0.24

Al-0.5Fe-0.25Si

0.52

0.26

2.00

5. Chemical composition effect

3. Effect of silicon level

Fig.1. True stress-true strain curves of Al-0.1Fe-0.1Si alloy at
various strain rates (a) 0.01 s-1, (b) 0.1 s-1, (c) 1 s-1 and (d) 10 s-1.

Fig.4. Relationship between (a) α (b) Q, (c) n, (d) lnA and
iron level by polynomial fit for Al-Fe-0.1 or 0.25Si.

Fig.3. Effect of silicon on flow stress at strain of 0.4,


(a)Al-0.1Fe;  = 0.01 s-1, (b) Al-0.1Fe;  = 10 s-1, (c) Al

0.5Fe,  = 0.01 s-1 and (d) Al-0.5Fe;  = 10 s-1.

  B0  B1Fe  B2 Fe 2

4. Constitutive equations
Arrhenius equation


  Af ( ) exp( 

Hyperbolic-sine law equation

Q  C0  C1Fe  C2 Fe

Zener-Holloman parameter


Z   exp(

Activation energy

Q  R[

2

n  D0  D1Fe  D2 Fe 2

Q
)
RT


  A[sinh( )]n exp( 

Fig.2. Effect of iron on flow stress at strain of 0.4, (a)Al

0.1Si, = 0.01 s-1, (b) Al-0.1Si;  = 10 s-1, (c) Al-0.25Si,


 = 0.01 s-1 and (d) Al-0.25Si;  = 10 s-1.

-

Results

1. Flow stress behavior

2. Effect of iron level

10

823

1.25

1

773

0.54

Al-0.3Fe-0.25Si

723

ln A  E0  E1Fe  E2 Fe 2



1



 Z 1/ n  Z 2 / n 1/ 2 
 

 
ln       1 
 
 A 
 A 
 




Z   exp(

Q
)
RT

Q
)
RT

Q
)  A[sinh( )]n
RT


 ln 
 ln[sinh( )]
]T [
]  RnS
 ln[sinh( )]
(1 / T )

Mohammad Shakiba
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

Fig.5. Correlation between the experimental and
predicted flow stress for; Al-0.5Fe-0.1Si.

Conclusions
Increasing the iron level from 0.1 to 0.7 and 0.1 to 0.5 in low and high silicon containing alloys produced 10-32% and 7-16% increase in flow
stress over the range of deformation conditions at strain of 0.4. Furthermore, raising the silicon level from 0.1 to 0.25 wt.% increased flow stress by
7-14% and 4-8% in Al-0.1Fe and Al-0.5Fe alloys respectively.
 The final results show the developed constitutive equations give an excellent estimate for the flow stress of all the investigated alloys.

Journée des étudiants – REGAL
The hot deformation behavior of Al-Fe-Si alloys containing various amounts of

Le comportement en déformation à chaud des alliages Al-Fe-Si contenant
différents pourcentage en fer et en silicium a été étudié par le biais des essais de
22 Octobre 2013
compression à chaud isothermes réalisées à différentes températures et vitesses
de déformation. La contrainte d’écoulement augmente avec la teneur en fer ou en
silicium pour l'ensemble des conditions de déformation. Les courbes contraintesdéformations réelles ont été utilisées pour développer les équations constitutives
des alliages Al-Fe-Si. Cependant, l’influence de la température et de la vitesse de
déformation sur le comportement des alliages Al-Fe-Si a été présentée par le
paramètre de Zener-Holloman. L'effet de la composition chimique a été incorporé
dans l'analyse constitutive en tenant compte de ses effets sur les constantes du
matériau. La comparaison entre la contrainte d’écoulement calculée et mesurée
montre que les équations constitutives proposées donnent une prévision précise
de la contrainte d'écoulement des alliages Al-Fe-Si.

iron and silicon was studied by isothermal hot compression tests conducted at
different temperatures and strain rates. The flow stress raised by increasing either
the iron or silicon content for all the deformation conditions. The measured true
stress- true strain curves were employed to develop constitutive equations for AlFe-Si alloys. However, the influences of temperature and strain rate on deformation
behavior were presented by Zener-Holloman parameter. The effect of chemical
composition was incorporated in the constitutive analysis by considering its
effect on material constants. Comparison between calculated and measured
flow stresses shows that the proposed constitutive equations give an ac