View
215
Download
0
Category
Preview:
Citation preview
Calorimetry on pure substances and complex non-equilibrium Al-systems
08.07.2016 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
Richard Kemsiesa
Benjamin Milkereita,b,c, Christoph Schickb,c, Olaf Kesslera,c
a,b,cUniversity of Rostock, Germany aChair of Materials Science,
bPolymer Physics Group cCALOR Calorimetry and Thermal Analysis Laboratory Rostock
GTT-Technologies' 18th Annual Users' Meeting
Herzogenrath, Germany
June 29 - July 1, 2016
08.07.2016 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP 2
• Motivation
• Differential Scanning
Calorimetry on Aluminium
alloys
• DSC Step Scan method
for cp measurement
heating
heat treatment of metallic materials
e. g. steels, Ni- & Co based superalloys, Al alloys, …
basic scheme applies for several materials
08.07.2016 3© 2009 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
ageing
T
t
solution annealing
SAT
RTC0
600
400
200
0
lα+l
α
α+β
CB
quenching
How slow to
dissolve everything?
full solution
How fast to freeze
supersaturated
solid solution?
avoid precipitation
08.07.2016 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP 4
• Motivation
• Differential Scanning
Calorimetry on Aluminium
alloys
• DSC Step Scan method
for cp measurement
08.07.2016 5© 2009 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE
S: sample furnace; R: reference
furnace (equal S), 1heating wire,
2 Thermopile; measuring
systems – separately – in
ambience of const. temperature
G.HÖHNE, W. HEMMINGER, H.FLAMMERSHEIM:
Differential Scanning Calorimetry, SPRINGER
Differential Scanning Calorimetry (DSC)
2 identical micro furnaces in symmetric system
PC controlled temperature programs: heating/ cooling
regulation: equal temperature
difference in heating power or heat flow measured
measurement of (tiny) heat
Differential Scanning Calorimetry (DSC)
ideal:
heating/ cooling empty system: signal = 0
thermal reaction in sample furnace: Signal ≠ 0
real:
certain asymmetry: device depending bending
correct: subtract baseline from sample measurement
functional principle
08.07.2016 6© 2009 UNIVERSITÄT ROSTOCK
Δ P
T
0
Δ P
T
0
specific reaction
heat
sample
measurement
baseline
100 200 300 400 500
0,9
1,0
1,1
exosp
ecific
he
at
in J
g-1K
-1temperature in °C
100 200 300 400 500
0,00
0,02
0,04
0,06
ecxe
ss s
pe
cific
he
at
in J
g-1K
-1
temperature in °C
exo
Preliminary tests Al alloys
cooling EN AW-6005A , 50 K/min
Perkin-Elmer Pyris 1
after: 540 °C 20 min
How to measure precipitation heat – Cp or excess-Cp?
08.07.2016 7
alloyed sample
pure Al sample
alloyed sample
empty
© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
100 200 300 400 500
-10
-5
0
5
heat
flow
in m
W
900 mg EN AW-6005A
without any package
100 200 300 400 500-2
0
2
heat
flow
in m
W
3600 mg EN AW-6005A
wrapt in pure Al-foile
100 200 300 400 500-1
0
1
2
3
4
°C
°C
heat
flow
in m
W
temperature in °C
1570 mg EN AW-6005A
packed in pure Al crucible
Preliminary tests Al alloys
important role of radiation losses
baseline stability
samples change surface color:
bright dark grey
radiation effect changing bending
bending reduction sample package!
Obligatory sample package!
08.07.2016 8
Sample-measurement
Baseline-measurement
subtraction of sample- &
baseline-measurement
Setaram 121 DSC
cooling with 0.5 K/min after
solution annealing: 540°C 20 min
© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
DSC measures heat effects
sample compared with inert reference sample
9© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
T
t
0 100 200 300 400 500 600-0.3
-0.2
-0.1
0.0
0.1
0.2
exothermic
AA6005A initial T4
temperature in °C
0.05 K/s
endothermic
exce
ss C
p in
Jg
-1K
-1
Challenge
Very large scale of technically & physically interesting heating & cooling rates!
10
1E-4 1E-3 0,01 0,1 1 10 100 1000 10000 100000
cooling rate in K/s
e.g. one cooling method – different component dimensions
MMG GmbH
auto-lexikon.de
weloe.de
fi-sch.de
© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
range depends on physical requirements alloy, heating/cooling procedure, dimensions
How to cover all relevant rates?
Use different DSC types and methods
08.07.2016 11UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
10-5
10-4
10-3
10-2
10-1
100
101
102
103
104
105
Milkereit et al., Thermochim. Acta 492 (2009) 73-78.
Zohrabyan et al.
Thermochim. Acta 529 (2012) 51-58.
Schumacher et al.
Thermochim. Acta
602 (2015) 63-73.
indirect
"Differential Reheating"
Chip Calorimeter, e. g.
Mettler-Toledo Flash DSC
Me
ttle
r-T
ole
do D
SC
82
3
0.1
s
1 s1 m
in
1 h1 d
1 m
o cooling rate in K/s
cooling duration 540 °C 20 °C
1 a
0.0
1 s
1 w
e
Seta
ram
C600 D
SC
Seta
ram
12
1 D
SC
Perk
in-E
lme
r P
yris 1
DS
C
indirect
"Reheating"
Setaram
121 DSC &
C600 DSC
direct in-situ cooling experiments
Continuous heating DSC AA6005A to 580 °C
suppression of reactions with increasing
rate
serious peak shift, e. g. peak b:
observed T: 160 K
thermal lag 10 K
0.01 – 5 K/s
12© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
0 100 200 300 400 500 600
initial T4
temperature in °C
0.1 K/s
0.05 K/s
0.01 K/s
0.5
Jg
-1K
-1
0.5 K/s
5 K/s
1 K/s
3 K/s
endo
exce
ss s
pe
cific
he
at
160 K
T
t
b
J. Osten et al.. Dissolution and Precipitation Behaviour during
Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating
Rates. Materials 2015, 8, 2830-2848. DOI: 10.3390/ma8052830
0 100 200 300 400 500 600
initial T4
temperature in °C
0.1 K/s
0.05 K/s
0.01 K/s
0.5
Jg
-1K
-1
0.5 K/s
5 K/s
1 K/s
3 K/s
endo
challenges for interpretation of DSC heating curves
DSC measures sum signal!
sum might be zero...
separation of overlapped reactions problem to
solve in future
serious overlapping several reactions
13© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
t
Jg-1
K-1
0endo
exo
Continuous cooling precipitation diagrams
08.07.2016 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP 14
T
t
α α + β
α α + B‘
precipitation start temperature
08.07.2016 15
0,5 mass% Mg2Si1
540
liquid
liquid
© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
mass % Si Mg …
1.23 1.05 …
mass % Si Mg …
0.4 0.44 …
Milkereit, B., et al. (2009). "Recording
of continuous cooling precipitation
diagrams of aluminium alloys."
Thermochimica Acta 492: 73-78. DOI:
10.1016/j.tca.2009.01.027
100 µm
Method
Which reactions occur when and how intensive?
16
tem
pera
ture
time
α α+ β
α
Which?
When & how
strong?
Structure analysis
Differential
Scanning
Calorimetry
t
T
100 200 300 400 500
0,00
0,05
cooling of an aluminium alloy
Jg-1
K-1
temperature in °C
exo
© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
time
10 µm
CCP-diagrams
Milkereit, B., et al. (2012). "Continuous cooling precipitation
diagrams of Al-Mg-Si alloys." Materials Science & Engineering A
550: 87-96. DOI: 10.1016/j.msea.2012.04.033
08.07.2016 UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP 17
• Motivation
• Differential Scanning
Calorimetry on Aluminium
alloys
• DSC Step Scan method
for cp measurement
cp measurement with DSC
high accuracy through step scan method
18© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
Al crucible
sample
hea
t flo
w
time
T
tem
pera
ture
sample sample
empty
𝑄𝑠𝑎𝑚𝑝𝑙𝑒 − 𝑄𝑒𝑚𝑝𝑡𝑦𝑑𝑡
𝑚 ∆𝑇
cp
temperature
C. Schick (2002): Temperature modulated differential scanning calorimetry
(TMDSC)- basics and applications to polymers In: Handbook of Thermal
Analysis and Calorimetry. Vol. 3: Applications to Polymers and Plastics
S.Z.D. Cheng, editor, pp. 713-810.
validity of the data?
calibration with sapphire
19© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
-100 0 100 200 300 400 500 600
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
cp
in J
/(g
K)
temperature in °C
sapphire literature
cp of sapphire (Al2O
3)
0.990
0.995
1.000
1.005
1.010
1.015
1.020
lite
ratu
re / m
ea
sure
men
t
• well known cp of sapphire
• after each sample measurement
error correction
sapphire literature
sapphire measurement
-100 0 100 200 300 400 500 600
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
uncorrected
cp in J
/(gK
)
temperature in °C
cp of Al5N5 (Al 99.995%)
uncorrected
corrected
correction factor
evaluating the data
comparison cp of pure Al with different literature sources
08.07.2016 20UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
-273.15 -73.15 126.85 326.85 526.85 726.85
0 200 400 600 800 1000
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0
5
11
16
22
27
32
38
cp
in J
/(m
ol K
)
temperature in K
DSC device 1
DSC device 2
Takahashi, 1989
Buyco, Davis 1970
Brooks 1969
Ditmars 1985
cp
in J
/(g
K)
temperature in °C
-100 100 300 500
173.15 373.15 573.15 773.15
0.8
0.9
1.0
1.1
1.2
22
24
27
30
32
cp
in J
/(m
ol K
)
temperature in K
DSC device 1
DSC device 2
Takahashi, 1989
Buyco, Davis 1970
Brooks 1969
Ditmars 1985
cp
in J
/(g
K)
temperature in °C
high correspondence between
literature and measurement
step scan application on intermetallic phases
aluminium alloys for long-term stable
electrical aluminium connections (ALLEE)
large collaborative project (GTT, Hydro Aluminium,
TU Dresden, RWTH Aachen)
goal:
long-term stable intermetallic phases (e.g. Al3Zr, Al3Ni)
also at elevated temperatures (140 °C)
challenge:
prediction (modelling) of precipitation and dissolution/growth
investigation of Al alloy: sum cp of all phases
solution:
investigation of pure intermetallic phases (Uni Jena, Germany)
why important?
08.07.2016 21UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
very difficult to produce!
intermetallic phases
08.07.2016 22UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
results
pure intermetallic phases Al3Zr, Al13Fe4, Al3Ni, Al10Fe3Ni
08.07.2016 23UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
150 300 450 600 750 9000.4
0.5
0.6
0.7
0.8
0.9
Al3Zr
Cp in J
/(g
K)
Temperatur in K
150 300 450 600 750 9000.4
0.5
0.6
0.7
0.8
0.9
Al10Fe3Ni
Cp in J
/(g
K)
Temperatur in K
150 300 450 600 750 9000.4
0.5
0.6
0.7
0.8
0.9
Al13Fe4
cp
in
J/(
gK
)
Temperatur in K
150 300 450 600 750 9000.4
0.5
0.6
0.7
0.8
0.9
Al3Ni
cp
in
J/(
gK
)
Temperatur in K
-100 100 300 500 700
173.15 373.15 573.15 773.15 973.15
0.5
0.6
0.7
0.8
13
16
19
22
temperature in K
cp
in J
/(m
ol K
)
Cp
in
J/(
gK
)
temperature in °C
Al3Zr-Fit
Al10Fe3Ni-Fit
Al13Fe4-Fit
Al3Ni-Fit
24© UNIVERSITY OF ROSTOCK | CHAIR OF MATERIALS SCIENCE & POLYMER PHYSICS GROUP
10-4
10-3
10-2
10-1
100
101
102
103
104
0
10
20
30
40
50
60
406080100120140160180200
HV
1 a
fter
agein
g
exce
ss c
p in
J/g
cooling rate in K/s
cooling EN AW-Al Zn8MgCu from 470 °C
0 100 200 300 400 500
0.00
0.05
0.10
0.15
0.20
0.25
cooling of EN AW-7150 after 480 °C 1 h
exce
ss c
p in
Jg
-1K
-1
temperature in °C
0.3 K/min
15 K/min
180 K/min
exo
-100 100 300 500 700
173.15 373.15 573.15 773.15 973.15
0.5
0.6
0.7
0.8
13
16
19
22
temperature in K
cp in J
/(m
ol K
)
Cp in J
/(gK
)
temperature in °C
Al3Zr
Al10Fe3Ni
Al13Fe4
Al3Ni
Recommended