re effect mo re welds-3
TRANSCRIPT
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Re Effect-MoRe Welds-3
2. Mo-Re alloys with two-phase precipitation : Mo-47 wt.% Re and Mo-50 wt.% Re
2-1. Mo-47 wt.% Re
Characteristics of Mo-47%Re alloy by Indentation and Microstructural Method*:
*Unpublished work :
M. I. Danylenkoa, T. Kadokura
b and K. Okamoto
b , A. V. Krajnikov
a, F. Morito
a, c,
a Institute for Problems of Materials Science, Kyiv, Ukraine b Allied Materials Corp. (ALMT), Toyama, Japan
c MSF Laboratory, Moriya, Japan
TEM observation & Microhardness : M. I. Danylenkoa
Fabrication of PM Mo-47%Re sheet : T. Kadokurab and K. Okamoto
b
Part I : as-rolled Mo-47%Re sheet
Material and experiment
Fabrication of PM Mo-47%Re sheet
Mo-47%Re alloy was produced by powder metallurgy. The purity of the starting raw powder
was 99.9 % or more both in Re and Mo. Re content reduced from 49.0 % in as-sintered state
to 47.0 % in the 1.0 mm sheet. After mixing raw powders were followed by pressing (CIP),
sintering in hydrogen, sintering in vacuum, hot rolling and annealing, finally the deformed
ingot of 110 L x 50 W x 25 mm H was manufactured. Then the processing of heating and
rolling at ambient temperature was repeated as follows to make Mo-Re sheet with a suitable
thickness.
Fig. 1 Sample of 1.0 mm thick Mo-47%Re sheet (Mo.jpg)
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Total (General ) accumulated Reduction(TR) <Rolling Ratio>
TR =94.0% by Hot Rolling (25-1.5mm) with Intermediate Annealing
Step 1 : TR=68.0% (25 - 8.0 mm)
Step 2 : TR=81.25% (8.0 - 1.5 mm)
Cold Rolling with Intermediate Annealing
Step 3 : TR=33.3% (1.5- 1.0 mm)
Step 4 : TR=10.0% (1.0-0.9 mm)
Step 5 : TR=11.1% (0.9-0.8 mm)
Step 6 : TR=37.5% (0.8-0.5 mm)
Step 7 : TR=20.0% (0.5-0.4 mm)
Step 8 : TR=32.5% (0.4-0.27 mm)
Table 1 Chemical content of PM Mo-47%Re
Element (ppm) C O N Al Ca Cr Cu Fe Mg Mn Ni Si Sn W
As-sintered 20 <10 <10 <5 <1 23 <1 6 <1 <1 <3 <20 <10 10
Sheet 10 <10 <10 <5 <1 2 1 5 <1 <1 3 <20 <10 10
Chemical content of 1.0 mm thick Mo-47%Re sheet is shown in Table 1. Microstructure was
examined by optical microscopy and transmission electron microscopy. Indentation test was
carried out by the indentator of 40 gf or 100 gf in IPMS. Vickers hardness was measured by
10 kgf indebtator in ALMT. Tensile properties of the as-rolled 1.0 mm thick sheet were tested
at RT, 773 K and 1273 K.
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Result and discussion
Fig. 2. Microstructure of (a) 1.0, ( b) 0.5, (c) 0.27 mm thick sheet in the as-rolled Mo-47%Re
alloys.
(a)
(a)
(b)
(c)
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(a) Mo-47Re : t=1.0mm, as-rolled
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(b) Mo-47Re : t=0.5mm, as-rolled
(b) Mo-47Re : t=0.27mm, as-rolled
Fig. 3. 3D photos of (a) 1.0, ( b) 0.5, (c) 0.27 mm thick sheet in the as-rolled Mo-47%Re
alloys.
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The results of microhardness measurement are summarized in Fig 3. The hardness increases
with deformation in a range of t=1 – t=0.8 (black line with down-triangles). At higher
deformation the level of hardness is stabilised. Simultaneously the hardness of different part
of the surface becomes non-uniform. The parts with lower hardness co-exist with other parts
demonstrating higher hardness (see blue up-triangles and red dots)
Fig. 4. Microhardness as a function of sheet thickness (P= 40g or 100g)
It is noteworsey that each sheet sample had different processing with extent of rolling
reduction, rolling deformation and so on. As a result, we could measured the microhardness
data as in Fig. 4.
Mo-47 wt.% Re hardens by the two-phase type Mo-Re alloys. Tendency of precipitation
hardening was similar to solution hardening (Fig. 5). Mo-50 wt.% Re also shows the same
tendency of an increase of hardening.
1,0 0,8 0,6 0,4 0,2
610
620
630
640
650
660
670
680
690
700
710
720
730
Mic
roh
ard
ne
ss
, k
G/m
m2
t
Soft phase
Middle phase
Hard phase
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Fig. 5. Hardness of Mo-Re alloys annealed at 1873 K for 3.6 ks.
As for lower and higher hardness among more thiner sheet, it is found that two or three phases
with different hardness were co-exist. The area with middle hardness means the co-existing of
both area.
For example, it is possible to observe several ppts along grain boundaries on TEM 8840854
(enlarged one of 5840855 ) in TD plane of t=0.27 mm sheet.
The diffraction pattern shows that they are sigma-phases along the texture boundary between
matrix.
Disappearance of texture [100] seems to connect with higher cold-hardened texture [111] and
starts to recrystallization, which expected that in high deformed states (after technological
annealing after 60%) disappearance of texture [100] would lead to decreasing of one in a two
peaks of microhardness.
Fig. 6. 3D photos of Mo-47%Re alloy with 0.5 mm thick. (a) as-rolled, (b) annealed at 1673
K, 1 h and (c) annealed at 1873 K, 1 h, respectively.
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Mo-47Re t=0.5mm as-rolled
100µm
RD
Fig. 6a 3D photos of as-rolled Mo-47%Re alloy with 0.5 mm thick.
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Mo-47Re t=0.5mm TA=1400℃
100µm
RD
Fig. 6b 3D photos of 0.5 mm thick Mo-47%Re alloy annealed at 1673 K, 1 h.
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Mo-47Re t=0.5mm TA=1600℃
100µm
RD
Fig. 6c 3D photos of 0.5 mm thick Mo-47%Re alloy annealed at 1873 K, 1 h.
Fig. 6. RD plane (gray color) : perpendicular plane to rolling direction = perpendicular plane
to RD
ND plane = Rolling plane : perpendicular plane to ND = (wide plane)
TD plane : perpendicular plane to TD direction (thickness / height)
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Fig. 7. Deformation band (blue) in rolled iron (red – rolling direction) by Kolja-san.
500 1000 1500 2000
200
250
300
350
400
450
500
550
600
650
Hv
Annealing temperature, K
1 mm 0.9 mm 0.8 mm 0.5 mm 0.27 mm
Fig. 8. Hardness (HV ; P=10kgf) as a function of annealing temperature (1 hr)
1 µµµµm
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200 400 600 800 1000 1200 1400
0
10
20
30
40
Elo
nga
tion,
%
Test temperature, K
Uniform elongation Total elongation
Fig. 9. Tensile properties of the as-rolled Mo-47%Re sheet with 1.0 mm thickness
Sigma phases in the matrix by TEM analysis
ND plane = Rolling plane : perpendicular plane to ND = (wide plane)
260 nm
Fig. 10. TEM microstructure in Mo-47%Re, t=1.0 mm<Mo-Re 1mm d0.jpg>
ppt size : specimen 4 : L=190 nm, W=150 nm, specimen 3 : L=400 nm, W=150 nm
Table 2. EDS analysis by TEM in Mo-47%Re, t=1.0 mm
200 400 600 800 1000 1200 1400
600
800
1000
1200
1400
1600
1800
2000
Str
ess,
M
Pa
Test temperature, K
Yeild stress Tensile stress
Mo-47%Re, t=1.0 mm
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Re (wt%) Mo (wt%)
Spectrum 1
Spectrum 2
Spectrum 3
Spectrum 4
I am sorry that I was missed measured values in the above Table.
Please ask Kolja whai is the correct values !!
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Fig. 11. TEM observation in RD plane in 0.27 mm thick sheet
Bright field
1 µm
Dark field
[111]
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Fig. 12. Diffraction pattern of second phase in Mo-47%Re alloy (indexing of spots has not
yet completed. If possible, please ask Kolja how to identify them).
0,5 µm
Mo sigma
1,1,-2 2
, 0
,-
2
1,0,-1 2,-1,-
1,-1,0
1,-1,0
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0.5 µm
Fig. 13. Fig. 11. TEM microstructure in Mo-47%Re, t=1.0 mm<Mo-Re 1mm d0.jpg>
Sigma phases in the matrix by TEM analysis
TD plane : perpendicular plane to TD direction (thickness / height)
220 nm
ppt size : L=95 nm, W=30 nm
Fig. 13a. Enlarged one of the last photo in Fig. 13.
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<<To making easier for checking these problems, I recommend you to anneal one sample at
1400 - 1600 degree C for half an hour or more. >>
Microstructure examination by TEM after annealing treatment is
not conducted yet. Therefore it is better to compare the
microstructural change in detail between as-rolled sheets and
annealed ones, I think.
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2-2. Mo-50 wt.% Re
Fig. 14. Bend properties of as-welded Mo-50 wt.% Re at 77 K.
200 µm
Fig. 15. Fracture surface of postweld annealed Mo-50 wt.% Re bend tested at 77 K, v= 10
mm/min.
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Fig. 16. XRD spectrum of Mo-50 wt.% Re postweld annealed at 1473 K for (a) 1 h, (b) 2 h..
Fig. 17. SEM microstructure of Mo-50 wt.% Re weld after 60 % deformed by warm rolling
and annealed at 1573 K for 1 h.
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Fig. 18. TEM microstructure of Mo-50 wt.% Re weld after 65 % deformed by warm rolling
and annealed at 1473 K for 1 h.
Attention!!
As-rolled Mo-50%Re welds were irradiated at HT by SM reactor
in RIAR.