- Email: [email protected]
The tensile strength of an Fe and a NiFe base amorphous alloy
Scripta METALLURGICA
Vol. 7, pp. 1161-1164, 1973 Printed in the United States
Pergamon Press,
Inc.
THE TENSILE STRENGTH OF AN Fe AND A Ni-Fe BASE AMORPHOUS ALLOY D. E. Polk and C. A. Pampillo Materials Research Center Allied Chemical Corporation Morristown, New Jersey 07960
{Received August 30, 1973) This note reports data on the mechanical properties of a Ni-Fe and an Fe base metallic glass, namely Ni49Fe29PI4B6AI2 and Fe76PI6C4Si2AI 2. A more detailed report on the strength and fracture characteristics of these amorphous solids will follow
(i).
Strips 0.i cm wide by 0.0025 cm thick were produced by a modified PondMaddin technique
(2).
They were analyzed by x-ray diffraction and transmission
electron microscopy and found to be amorphous.
Pieces 6 cm long were cut out
of the strips and polished down to a width of about 0.04 cm. were pulled in a table model Instron machine at a cross-head
The specimens speed of ~0.3 cm/
min., using a set of specially designed tensile grips that avoid stress concentrations at the jaws. Figs.
1 and 2 show the tensile strength as a function of temperature for
the Fe base and Ni-Fe base glasses respectively.
The data shown at each tem-
perature gives the mean value obtained for five specimens and the errors quoted are the averages of the absolute values of the deviations
from the mean.
The graphs also show the apparent Young's modulus as a function of temperature as obtained from the load elongation curve after correction for the compliance of the tensile machine.
Because this technique is not precise,
these values should be taken as approximate
(they are probably about 20 to 30%
below the real values). It is apparent from Figs.
1 and 2 that the behaviors of the two glasses
at low temperatures are quite different.
The tensile strength of the Ni-Fe
base glass increases monotomically with decreasing of ~375,000 psi at 76°K. at low temperatures.
In contrast,
temperature up to a value
the pure Fe base glass becomes brittle
This begins at ~200°K where the tensile strength that
has reached 365,000 psi, starts to decrease
slowly with decreasing
The decrease in strength becomes catastrophic below 125°K.
temperature.
The temperature
dependence of the tensile strength of the Ni-Fe base glass below about room temperature and the Fe base glass from about room temperature down to 200°K is 1161
1162
TENSILE
STRENGTH
OF Fe A N D Ni-Fe
BASE A M O R P H O U S
ALLOY
Vol.
7, No.l]
I Fe76 PI6 C4 Si E AlE
/ / /
200;
~
~
~
I -° L~
APPARENT
I I00
I 200
~_
~ YOUNGS MODULUS
I 300 TEMPERATURE,
FIG.
400 -
[ 400 °K
1
Ni49
F e 2 9 P I 4 BE A12
_ 300
~A P P A . E ~
200
% ~0
L }
I
I 2 O0
IO 0
I 300 TEMPERATURE,
FIG.
much greater
than
that found
Pd.775Cu.06Si.165 different atomic
interactions
Several
other
all t e m p e r a t u r e s , were
always
This m e a n s across
(3) and
temperature
features
were
the n o r m a l s
strength
are m o s t
flow stress
of P d . 8 0 S i . 2 0
likely r e l a t e d
found
to the
has o c c u r r e d
This
fracture
about room
to be d i f f e r e n t
to the f r a c t u r e
45 ° r e l a t i v e
that f r a c t u r e
the thickness. above
0.2% c o m p r e s s i v e
the tensile
coefficients
OK
2
of
below
0°C.
The
to the d i f f e r e n t
in each of the glasses.
inclined
temperatures
for the
I 400
surfaces
tensile
axis
along planes mode
temperature.
is found Below
for the two glasses. of the N i - F e
and the thickness
of m a x i m u m
shear
in the F e - b a s e this
temperature
At
base glass vector.
stress
glass
only at
fracture
Vol.
7, No.
ii
TENSILE S T R E N G T H OF Fe AND Ni-Fe BASE A M O R P H O U S ALLOY
1163
surfaces were normal to the tensile axis.
This suggests a rather more b r i t t l e
b e h a v i o r b e l o w r o o m temperature.
this glass remains strong down to
However,
about 125°K. The t o p o g r a p h y of the fracture surfaces on the N i - F e and Fe b a s e glasses, to be r e p o r t e d m o r e e x t e n s i v e l y these findings.
Changes
in a f o r t h c o m i n g paper
(i), is c o n s i s t e n t w i t h
in the m i c r o s c o p i c mode of failure are found at around
room t e m p e r a t u r e and b e l o w about 200°K for the Fe base glass.
For the Ni-Fe
base glass only one m i c r o s c o p i c mode of failure is present at all temperatures. This mode is similar to that r e p o r t e d for Pd-Si glasses by Leamy et al. further d i s c u s s e d by P a m p i l l o and R e i m s c h u e s s e l
(5) and
(6).
The data shown c l e a r l y indicates that an e m b r i t t l i n g effect occurs at low temperatures
in the Fe base glass and t h a t this p h e n o m e n a is not p r e s e n t in the
Ni-Fe base glass down to 76°K.
W h e t h e r the e f f e c t is a ductile to b r i t t l e
t r a n s i t i o n similar to that o b s e r v e d
in Fe and some of its alloys, or an envi-
r o n m e n t a l e f f e c t is not clear as yet.
In the former case Ni w o u l d appear to
play the same t o u g h e n i n g role as in c r y s t a l l i n e alloys; act to p r e v e n t the e n v i r o n m e n t a l effect at the surface.
in the latter Ni may The fact that the
fracture t o p o g r a p h y and hence the m i c r o s c o p i c mode of fracture changes at the transition
s u g g e s t s a ductile to brittle t r a n s i t i o n rather than an environ-
mental effect.
References C. A. P a m p i l l o and D. E. Polk, R. Pond,
Jr. and R. Maddin,
to be published.
Trans. A I M E 245, 2475
C. A. P a m p i l l o and H. S. Chen,
to appear in Mat.
T. M a s u m o t o and R. Maddin, Acta Met. H. J. Leamy,
19, 725
(1969). Sc. and Eng.
(1971).
H. S. C h e n and T. T. Wang, Met. Trans.
C. A. P a m p i l l o and A. C. Reimschuessel,
3, 699
(1972).
to be published.
Acknowledgement Thanks are due to R. A. Costa and A. F. P r e z i o s i for their help w i t h the experiments.
Thanks are also due to Dr. J. J. Gilman for his e n c o u r a g e m e n t
and for r e v i e w i n g the manuscript.
Vol. 7, pp. 1161-1164, 1973 Printed in the United States
Pergamon Press,
Inc.
THE TENSILE STRENGTH OF AN Fe AND A Ni-Fe BASE AMORPHOUS ALLOY D. E. Polk and C. A. Pampillo Materials Research Center Allied Chemical Corporation Morristown, New Jersey 07960
{Received August 30, 1973) This note reports data on the mechanical properties of a Ni-Fe and an Fe base metallic glass, namely Ni49Fe29PI4B6AI2 and Fe76PI6C4Si2AI 2. A more detailed report on the strength and fracture characteristics of these amorphous solids will follow
(i).
Strips 0.i cm wide by 0.0025 cm thick were produced by a modified PondMaddin technique
(2).
They were analyzed by x-ray diffraction and transmission
electron microscopy and found to be amorphous.
Pieces 6 cm long were cut out
of the strips and polished down to a width of about 0.04 cm. were pulled in a table model Instron machine at a cross-head
The specimens speed of ~0.3 cm/
min., using a set of specially designed tensile grips that avoid stress concentrations at the jaws. Figs.
1 and 2 show the tensile strength as a function of temperature for
the Fe base and Ni-Fe base glasses respectively.
The data shown at each tem-
perature gives the mean value obtained for five specimens and the errors quoted are the averages of the absolute values of the deviations
from the mean.
The graphs also show the apparent Young's modulus as a function of temperature as obtained from the load elongation curve after correction for the compliance of the tensile machine.
Because this technique is not precise,
these values should be taken as approximate
(they are probably about 20 to 30%
below the real values). It is apparent from Figs.
1 and 2 that the behaviors of the two glasses
at low temperatures are quite different.
The tensile strength of the Ni-Fe
base glass increases monotomically with decreasing of ~375,000 psi at 76°K. at low temperatures.
In contrast,
temperature up to a value
the pure Fe base glass becomes brittle
This begins at ~200°K where the tensile strength that
has reached 365,000 psi, starts to decrease
slowly with decreasing
The decrease in strength becomes catastrophic below 125°K.
temperature.
The temperature
dependence of the tensile strength of the Ni-Fe base glass below about room temperature and the Fe base glass from about room temperature down to 200°K is 1161
1162
TENSILE
STRENGTH
OF Fe A N D Ni-Fe
BASE A M O R P H O U S
ALLOY
Vol.
7, No.l]
I Fe76 PI6 C4 Si E AlE
/ / /
200;
~
~
~
I -° L~
APPARENT
I I00
I 200
~_
~ YOUNGS MODULUS
I 300 TEMPERATURE,
FIG.
400 -
[ 400 °K
1
Ni49
F e 2 9 P I 4 BE A12
_ 300
~A P P A . E ~
200
% ~0
L }
I
I 2 O0
IO 0
I 300 TEMPERATURE,
FIG.
much greater
than
that found
Pd.775Cu.06Si.165 different atomic
interactions
Several
other
all t e m p e r a t u r e s , were
always
This m e a n s across
(3) and
temperature
features
were
the n o r m a l s
strength
are m o s t
flow stress
of P d . 8 0 S i . 2 0
likely r e l a t e d
found
to the
has o c c u r r e d
This
fracture
about room
to be d i f f e r e n t
to the f r a c t u r e
45 ° r e l a t i v e
that f r a c t u r e
the thickness. above
0.2% c o m p r e s s i v e
the tensile
coefficients
OK
2
of
below
0°C.
The
to the d i f f e r e n t
in each of the glasses.
inclined
temperatures
for the
I 400
surfaces
tensile
axis
along planes mode
temperature.
is found Below
for the two glasses. of the N i - F e
and the thickness
of m a x i m u m
shear
in the F e - b a s e this
temperature
At
base glass vector.
stress
glass
only at
fracture
Vol.
7, No.
ii
TENSILE S T R E N G T H OF Fe AND Ni-Fe BASE A M O R P H O U S ALLOY
1163
surfaces were normal to the tensile axis.
This suggests a rather more b r i t t l e
b e h a v i o r b e l o w r o o m temperature.
this glass remains strong down to
However,
about 125°K. The t o p o g r a p h y of the fracture surfaces on the N i - F e and Fe b a s e glasses, to be r e p o r t e d m o r e e x t e n s i v e l y these findings.
Changes
in a f o r t h c o m i n g paper
(i), is c o n s i s t e n t w i t h
in the m i c r o s c o p i c mode of failure are found at around
room t e m p e r a t u r e and b e l o w about 200°K for the Fe base glass.
For the Ni-Fe
base glass only one m i c r o s c o p i c mode of failure is present at all temperatures. This mode is similar to that r e p o r t e d for Pd-Si glasses by Leamy et al. further d i s c u s s e d by P a m p i l l o and R e i m s c h u e s s e l
(5) and
(6).
The data shown c l e a r l y indicates that an e m b r i t t l i n g effect occurs at low temperatures
in the Fe base glass and t h a t this p h e n o m e n a is not p r e s e n t in the
Ni-Fe base glass down to 76°K.
W h e t h e r the e f f e c t is a ductile to b r i t t l e
t r a n s i t i o n similar to that o b s e r v e d
in Fe and some of its alloys, or an envi-
r o n m e n t a l e f f e c t is not clear as yet.
In the former case Ni w o u l d appear to
play the same t o u g h e n i n g role as in c r y s t a l l i n e alloys; act to p r e v e n t the e n v i r o n m e n t a l effect at the surface.
in the latter Ni may The fact that the
fracture t o p o g r a p h y and hence the m i c r o s c o p i c mode of fracture changes at the transition
s u g g e s t s a ductile to brittle t r a n s i t i o n rather than an environ-
mental effect.
References C. A. P a m p i l l o and D. E. Polk, R. Pond,
Jr. and R. Maddin,
to be published.
Trans. A I M E 245, 2475
C. A. P a m p i l l o and H. S. Chen,
to appear in Mat.
T. M a s u m o t o and R. Maddin, Acta Met. H. J. Leamy,
19, 725
(1969). Sc. and Eng.
(1971).
H. S. C h e n and T. T. Wang, Met. Trans.
C. A. P a m p i l l o and A. C. Reimschuessel,
3, 699
(1972).
to be published.
Acknowledgement Thanks are due to R. A. Costa and A. F. P r e z i o s i for their help w i t h the experiments.
Thanks are also due to Dr. J. J. Gilman for his e n c o u r a g e m e n t
and for r e v i e w i n g the manuscript.