presentation yuna
DESCRIPTION
sTRANSCRIPT
Effect of solidification through cross-section change on dendritic array morphology in single crystal castings
Yuna Marcos dos Anjos
Chemical and Biomedical Engineering Department
Cleveland State University
Summer 2015
OutlineIntroduction
Directional Solidification Mushy Zone Phase Diagram
Experiment Images- Contraction
Data Analysis and Results
Conclusions
Introduction
Directional solidification
G = 45 K/cm
Mushy Zone
Solutally Neutral Melt
Similar Densities ρAl: 2.375 g/cm3
ρSi: 2,57 g/cm3
Phase diagram
ExperimentWhat we have done?
Al-7%wt Si Alloy was melted and directionally solidified with growth speeds : 10.55, 29.4, and 73.26 μm/s.
The sample was sectioned and the cut parts were mounted in epoxy and polished
For each sample we took pictures using microscopy, and we create montages from individual micrographs.
These montages were analyzed by image analysis techniques to measure primary dendrite spacing and formation of spurious grains.
Images- ContractionGrowth Rate 10.55 μm/s
Images- ContractionGrowth Rate 29.40 μm/s
Images- ContractionGrowth Rate 73.26 μm/s
Why that deformation happens?
Data Analysis and ResultsPrimary Dendrite Nearest-Neighbor Spacing
dependence
Nearest-Neighbor Spacing/Primary Spacing Ratio dependence
Fraction Eutectic dependence
Primary trunk diameter
Primary Dendrite Nearest-Neighbor Spacing dependence
-40 -20 0 20 40200
500
800
1100
10.55 μms-1 ( Al 7%wt Si / 5-14-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
N
sp
acin
g,
μm
Primary Dendrite Nearest-Neighbor Spacing dependence
-40 -20 0 20 40200
500
800
29.4 μms-1 ( Al 7%wt Si / 5-12-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
N s
pac-
ing
, μ
m
Primary Dendrite Nearest-Neighbor Spacing dependence
-40 -20 0 20 40200
500
800 73μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
N s
pac-
ing
, μ
m
Nearest-Neighbor Spacing to Primary Dendrite Trunk Ratio dependence
-40 -20 0 20 402
3
4
5
6
7
810.55 μm.s-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
Nsp
ac-
ing
/ P
rim
ary
Den
dri
te T
run
k
Dia
mete
r
Nearest-Neighbor Spacing to Primary Dendrite Trunk Ratio dependence
-40 -20 0 20 405
5.5
6
6.5
7
7.5
829.4 μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
Nsp
ac-
ing
/ P
rim
ary
Den
dri
te
Tru
nk D
iam
ete
r
Nearest-Neighbor Spacing to Primary Dendrite Trunk Ratio dependence
-40 -20 0 20 405
5.5
6
6.5
7
7.5
873μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Den
dri
te N
Nsp
ac-
ing
/ P
rim
ary
Den
dri
te
Tru
nk D
iam
ete
r
Fraction Eutectic
-40 -20 0 20 400.3
0.32
0.34
0.36
0.38
0.4
0.42
0.44
10.55 μm.s-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Fra
cti
on
Eu
tecti
c
Fraction Eutectic
-40 -20 0 20 400.3
0.31
0.32
0.33
0.34
0.35
0.36
0.37
0.38
29.4 μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Fra
cti
on
Eu
tecti
c
Fraction Eutectic
-40 -20 0 20 400.3
0.32
0.34
0.36
0.38
0.4
0.42
73μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Fra
cti
on
Eu
tecti
c
Why the eutectic fraction change?
Primary Trunk Diameter
-40 -20 0 20 40130
140
150
160
170
180
190
10.55 μm.s-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Tru
nk D
iam
ete
r, μ
m
Primary Trunk Diameter
-40 -20 0 20 4080
85
90
95
100
105
110
115
120
29.4 μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Tru
nk D
iam
ete
r, μ
m
Primary Trunk Diameter
-40 -20 0 20 4060
65
70
75
80
85
90
95
100
73μms-1 ( Al 7%wt Si / 5-7-15)
Distance from the section change, mm
Pri
mary
Tru
nk D
iam
ete
r, μ
m
ConclusionCross-section contraction has minimum or no
effect on trunk diameter.
Cross-section contraction did not form spurious grains at these growth speeds
Increase in growth speed indicates to lowered primary spacing and trunk diameter
Sources ANALYSIS OF MICROSTRUCTURE AND MACROSEGREGATION FOR
DIRECTIONAL SOLIDIFICATION OF AL-7 WT% SI ALLOY WITH A CROSS-SECTION CHANGE AT GROWTH SPEEDS OF 10 AND 29.1 μM/S. Luke Johnson, Cleveland State University, (2013)
EFFECT OF CONVECTION ASSOCIATED WITH CROSS-SECTION CHANGE DURING DIRECTIONAL SOLIDIFICATION OF BINARY ALLOYS ON DENDRITIC ARRAY MORPHOLOGY AND MACROSEGREGATION. Masoud Ghods. Cleveland State University. (2015)