ENCYCLOPÉDIE DE LA RECHERCHE SUR L’ALUMINIUM AU QUÉBEC 2013 | Page 45
NOUVEAUX PRODUITS ET MATÉRIAUX À BASE D'ALUMINIUM
NEW ALUMINIUM BASED PRODUCTS AND MATERIALS
43
DÉVELOPPEMENT DE NOUVEAUX ALLIAGES À BASE
D'ALUMINIUM POUR LA PERFORMANCE À HAUTE TEMPÉRATURE
Development of New Aluminum-Based Alloys
DEVELOPMENT OF NEW ALUMINUM-BASED ALLOY
for High Temperature PerformanceHIGH TEMPERATURE PERFORMANCE
FOR
G.H. Garza-Elizondo,1 S.A. Alkahtani,2 A.M. Samuel,1 F.H. Samuel 1
2
1 Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada, G7H 2B1
College of Engineering, Salman bin Abdulazis University, AlKharj, Saudi Arabia
OBJECTIVES
INTRODUCTION
Current research in the automotive industry, based on the continued usage of traditional fuels such as oil or
gasoline, are focused on reducing fuel consumption and decreasing fossil fuel emission. Reduced fuel consumption
and, consequently, lower emission may be achieved either by significantly improving the efficiency of the car
engine or by bringing about a sizeable reduction in total car weight. While the applications in Al-Si casting alloys
should generally be carried out at temperatures of no more than 230 C, for certain applications such as those
required by the automotive industry, these alloys may operate over a wide range of conditions where temperatures
are liable to rise much higher than 230 C. The use of nickel and zirconium as additions to increase high
temperature strength in aluminum alloys is based on the production of precipitates in the form of Al3Ni and Al3Zr,
respectively; such particles are better able to support overaging at higher temperatures than precipitates such as
Al2Cu and Mg2Si, normally present in cast aluminum alloys.
•
•
•
The understanding of the effects of additions of nickel
and zirconium, on the strength of the cast aluminum
alloy 354 at high temperatures.
Investigating the influence of Ni and Zr on the strength
and the quality of as-cast and T6 heat-treated castings
at room temperature, and at high temperatures for
different holding times.
Analysis of the fracture mechanism in terms of the
crack initiation and crack propagation processes
occurring during the tensile testing.
EXPERIMENTAL PROCEDURES
Alloy
A
B
C
Element (wt%)
Si
Fe
Cu Mn Mg
Ti
Sr
Ni
Zr
Al
9.40 0.08 1.85 0.01 0.49 0.22 0.015 87.6
9.00 0.08 1.85 0.00 0.45 0.21 0.013 0.20 0.20 87.8
9.10 0.08 1.86 0.00 0.46 0.22 0.012 0.40 0.40 87.6
Material
Solution treatment at
505C/8 hrs, followed by
rapid quenching in water
(65C) and subsequent
artificial aging at 190C/2
hrs.
High temperature
tension test
Chemical analysis
Melting
ASTM B108 mold
and casting
Casting
Modification and/or
addition of elements
Tensile bars
T6 heat treatment
Tension test at room
temperature
Samples were
tested at
155C & 300C
temperatures
for holding
times ranging
from 10 hrs to
100 hrs.
Optical
microscopy and/or
SEM (EDS)
RESULTS
TENSILE TEST RESULTS
UTS (MPa)
YS (Mpa)
430
380
330
330
280
280
230
230
180
180
%Elongation
430
380
As-Cast
FRACTURE SURFACE
After T6
10 hours
40 hours
Alloy A
Alloy B
100 hours
3,50
3,00
2,50
2,00
1,50
1,00
0,50
As-Cast
Alloy C
After T6
10 hours
40 hours
Alloy A
Alloy B
0,00
Alloy C
(a)
100 hours
As-Cast
After T6
10 hours
40 hours
Alloy A
Alloy B
Alloy C
(b)
100 hours
(c)
Tensile test results for the alloys A, B and C tested at room temperature and at 155C : (a) UTS; (b) YS; and (c) El (%).
UTS (MPa)
YS (MPa)
500
400
300
200
100
0
As-Cast
After T6
10 hours
40 hours
Alloy A
Alloy B
Alloy C
(a)
100 hours
400
350
300
250
200
150
100
50
0
(a)
(b)
(c)
Optical micrographs of alloy C at 50x showing the fracture surface of (a)
as-cast & (b) T6 heat-treated samples under room temperature testing, &
(c) T6-treated sample under 300C/100 hrs testing conditions.
%Elongation
35,00
30,00
(a)
25,00
20,00
(b)
(c)
15,00
Guillermo Hernán Garza Elizondo
Agnès-Marie Samuel
Fawzy Hosny Samuel
Université du Québec
à Chicouitmi
10,00
5,00
As-Cast
After T6
10 hours
40 hours
Alloy A
Alloy B
Alloy C
(b)
100 hours
0,00
As-Cast
After T6
Alloy A
10 hours
40 hours
Alloy B
Alloy C
100 hours
(c)
Tensile test results for the alloys A, B and C tested at room temperature and at 300C : (a) UTS; (b) YS; and (c) El (%).
(d)
Saleh A. Alkahtani
College of Egineering,
Addulazis University,
Salman bin
Backscattered images of alloy C : (a) as-cast, (b) T6 heat-treated, (c) at
high temperature 300C/100 hrs & (d) EDS spectrum corresponding to the
AlCuMgNi phase circled in (c).
CONCLUSIONS
1. The addition of 0.4%Ni + 0.4%Zr (Alloy C) is not sufficient to resist softening at 300C. (cf. UTS: 52MPa, YS: 45MPa, %El: 22% with UTS: 359 MPa YS: 343, %El: 1.23,
observed after T6 treatment).
2. Addition of Zr + Ni increase the high temperature tensile properties, in particular for alloy B, containing 0.2%Ni and 0.2% Zr.
3. The percentage elongation increases with the testing temperature, from as-cast, to T6 heat-treated, to alloys tested at 155C and 300C temperatures, respectively.
4. The microstructure beneath the fracture surface reveals elongation of dendrites in the direction of the loading axis. The fracture surfaces of T6 heat-treated samples and those
tested at 300C show mainly coarse and deep dimples, compared to the shallow dimples observed on the fracture surface of as-cast samples.
Journée des étudiants – REGAL
L’amélioration de la résistance à des températures élevées a été un objectif
Improved strength at elevated temperatures has been a continuing goal in
Palais des congrès de Montréal, QC, Canada, 22 octobre 2013
constant dans le développement des alliages d'aluminium depuis plus de
aluminum alloy development for more than three decades. Aluminum-silicon cast
trois décennies. Les conditions d’utilisation des pièces de fonderie aluminiumcomponents are generally limited to service conditions of no more than 230°C.
silicium ne peuvent généralement dépasser 230°C. Pour certaines composantes
For certain automotive components however, operating conditions can vary over
automobiles toutefois, les conditions d'exploitation peuvent varier sur une large
a wide range of temperatures and stress conditions, with temperatures going
gamme de températures et de contraintes, avec des températures alla