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Phase investigation of an iron meteorite from Akyumak
Journal of
Materials Processing Technology ELSEVIER
Journal of Materials Processing Technology 57 (1996) 221-224
Phase investigation of an iron meteorite from Akyumak ilhan Aksoy a, Mehmet Ceylan b,*, Nejdet Kayali b a in6nii University, Science and Arts Faculty, Malatya, Turkey b Firat University, Science and Arts Faculty, Elazi~, Turkey Received 21 November 1994
Industrial summary
The phase of an iron meteorite which fell near Akyumak, East Anatolia, in 1981 have been investigated by optical and X-ray diffraction. Diffraction peaks of kamacite, teanite, plessite and cementite phases were separated and indexed by the related unit cell parameters of the phases. From the analysis of DSC and DTA curves, some phase transformation are known to have occurred during different heating regimes.
I. Introduction
An iron meteorite fell near Akyumak, Turkey in 1981, its mass being about 4 5 - 5 0 kg. A small fragment of the meteorite is in Elazi[g Military Museum, and the main mass of about 19 kg is in the Department of Geology, University of F/rat (Fig. 1). Certain physical and chemical properties of the meteorite were explored. Surface cavities and internal cavities were discovered and Widmanstatten patterns were discussed [1]. The average composition of the meteorite was given as 92.3 _+ 0.3 wt.% Fe and 7.7 +_ 0.1 wt.% Ni. Neuman bands were discovered [2]. In the present study, possible phases of the Akyumak meteorite have been examined by the optical microscope, X-ray diffraction and thermal analysis methods.
(a)
(h) Fig. 1. The main mass of the Akyumak meteorite. * Corresponding author. 0924-0136/96/$15.00 © 1996 Elsevier Science S.A. All rights reserved S S D I 0924-0136(95)02080-6
Fig. 2. Surface photographs of the meteorite, where K, T, P are kamacite, teanite and plessite phases and N relates to the highernickelized regions ( x 750).
). Aksoy et al./Journal of Materials Processing Technology 57 (1996) 221 224
222
3
11I
II
0
A 14.5
20
40
60
----~20
1/~5
20
40
60
--> 20 Fig. 4. Superposed diffractogram obtained from three diffractograms of the samples and selected peaks.
Fig. 3. X-ray diffractograms of the samples using a Mo target: I. outside powdered sample; II. mid-depth powdered sample; and III. core region powdered sample (background and smoothing elimination was used).
Table 1 Experimental data from Fig. 4
2. Experimental
No.
20 (o)
d (A)
T h e s a m p l e s u s e d in t h i s s t u d y w e r e o b t a i n e d b y c u t t i n g w i t h a steel s a w f r o m d i f f e r e n t r e g i o n s o f t h e Akyumak meteorite.
1 2 3
Two samples were prepared from the outside and the
4 5 6 7
16.40 18.25 20.49 25.75 28.07 28.99 31.02 31.62 35.63 36.65 38.55 41.24 46.53 49.05 51.14 55.61
2.487 2.236 1.994 1.592 1.462 1.417 1.326 1.302 1.159 1.128 1.074 1.007 0.898 0.854 0.822 0.760
i n s i d e b y c u t t i n g a slice w i t h a steel s a w , t h e s e s a m p l e s then being polished and etched. Surface photographs of these
samples were
taken
using
an
Olympus
BME
8
(Figs. 2(a) a n d (b)).
9
In addition to these, three samples were powdered from the outside, the mid-depth and the core of the meteorite, and X-ray diffractograms obtained by using
10 11 12 13
a Rigaku-Geigerflex diffractometer and
target
14
( F i g . 3). D i f f r a c t i o n p e a k s o f t h e p h a s e s w e r e d e t e r mined by the finger-print method.
15 16
a Mo
Table 2 Phase peaks and their related indices of the phases in the observed diffraction pattern of the iron meteorite from Akyumak Peak No.
20 (°)
Ni
1
16.40 18.25 20.49 25.75 28.07 28.99 31.02 31.62 35.63 36.65 38.55 41.24 46.53 49.05 51.14 55.61
011 . -012 --. ---. --223,014 --
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Kamacite ct-Fe
.
Teanite y-Fe
.
.
.
.
. -----
011 --002 .
.
. 022 -222 ---
.
Plessite (Ni, Fe) AsS
-012 112 --
022 013 --
--013
023 -114, 033 ---
023 004 114, 033 133 --
.
Cementite Fe3C2
.
.
.
-112 -.
Teanite 57.7% Fe 40.8 Ni, 0.5% P
122,003 123 004 223,014 024 124 134,015 333,115 125 33,035 335 444 155 346
003 211 203, 130 301 311 312 320 233, 205 330, 215 143, 402 333, 051 501 415, 154 434 524
223
i. Aksoy et al./ Journal of Materials Processing Technology 57 (1996) 221-224
't
'
t,~wl
-S.
.
.
.
.
"l'-g¢~~1163"3°6
I
too
200
.
.
~ ; o-c
.,1,
I
I
3o0
I
I
4oo
5oo
:~ [*C I
(a)
975.1~
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- 245.1
I
7 50
..
I
,,,I
I
900
I
I
I
1200
1050
~['C l
(b)
Fig. 5. For the mid-section sample of the Akyumak meteorite: (a) DSC curve for 5 °C min-~ heating rate; (b) DTA curve for 10 °C rain-~ heating rate. In these curves, negative: and positive energies are absorbed and released by the sample, respectively, these absorbed and released energies corresponding to phase transformations.
224
1. Aksoy et al./Journal of Materials Processing Technology 57 (1996) 221-224
At the same time, about 30-50 mg pieces, cut from the mid-section of the meteoritic sample, were investigated using a Shimadzu differential scanning calorimeter (DSC-50) and differential thermal analyzer (DTA-50) see Figs. 5(a) and (b). The transformation energies required were determined from heating curves, as seen on the plots.
3. Results and discussion
As shown in Figs. 2(a) and (b), the surface photographs of the polished and etched meteorite samples show heavy dark, dark gray and bright gray regions, which means that the meteorite is a mixture of different phases. Some possible phases of the Akyumak meteorite were explored in [1,2] by the photographic method. In both of the papers [1,2] the authors reported that the main phases of the meteorite are kamacite, teanite and plessite. Here kamacite and teanite are in regular patterns, whilst plessite is a mixture of kamacite and teanite or a mixture of teanite and martensite. Some possible phases have been marked on the photographs of the surface (Figs. 2(a) and (b)), in which photographs, K denotes kamacite, T related to teanite and P means plessite, whilst N corresponds to the higher-nickelized regions. The three diffractograms in Fig. 3 were supposed for the sake of simplicity of phase analysis, the single superposed diffractogram displaying the possible phase peaks of the meteorite. This superposed diffractogram is presented in Fig. 4 and the related diffraction data given in Table 1. The possisble phase of an Iron-Nickel meteorite have been considered as: (1) Ni phase (a = 3.5238 b.c.c.); (2) e-Fe (kamacite) phase (a = 2.8664 A b.c.c.); (3) c(Fe (a = 2.8750 ~ b.c.c,); (4) ~-Fe (teanite) (a = 3.6468 A f.c.c.); (5) 57.7wt.%Fe 40.8wt.%Ni0.5wt.%P-others (teanite), ( a = 3 . 6 0 A cubic); (6) mixture of teanite and kamacite (Ni, Fe) AsS (plessite), ( a = 5.90A cubic); and (7) Fe3C2 (cementite), ( a = 4.5235 A, b = 5.0888 A, c = 6.7431 A orthorhombic).
By comparing the calculated 20 with the related unit cell parameters [4] and observed 20, the phase peaks were matched and indexed for every phase given above, these results being presented in Table 2. The maximum error of all indexed lines was considered as about the full width at half maximum of a diffraction peak. Because some diffraction peaks of the phases are very near to each other these peaks may be superposed. As shown in Table 2, the e'-Fe phase was not observed. In the diffraction pattern, all of the peaks contain cementite (except for the 16.40 ° peak) and plessite (except for the 16.40 ° and 18.25 ° peaks). In the pattern, the 16.40 ° peak is undoubtedly a Ni peak and the 18.25 ° peak is cementite. The other peaks of the ptterns are the superposed peaks of the phases. Some superlattices can occur in iron meteorites [5]. From the DSC curve, different kinds of phase transformations are known to have occurred in the sample at temperatures of 163.3 °C and 441.0 °C (Fig. 5(a)). During the transformation, the sample, about 50 rag, absorbed 25.85 mJ at 163.3 °C and released 407.27 mJ at 441.0 °C. From the DTA curve (Fig. 5(b)), the first phase change is seen in the temperature range 747.4-769.6 °C, the sample absorbing about 2806.22 mJ in this range. Furthermore, some phase changes occurred also at temperatures of 872.3, 978.8, 1073.4 and 1212 °C, the same sample absorbing about 105235.45 mJ in the temperature range 872.3-1212 °C. These results mean that the energies absorbed by this sample correspond to phase transformations during this heating regime. References
[1] M. Ceylan,J. Firat Univ., 2(2) (1987) 41-50. [2] K. ~olako~lu and M. Ceylan, Meteoritics, 23 (1988) 371-372. [3] E. Anders, Origin age and composition of meteorites, Space Sci. Rev., 3 (1964) 583-714. [4] Handbook of Chemistry and Physics, 63rd edn. CRC Press, Boca Raton, FL, 1982-83. pp. E. 193-197. [5] K.B. Reuter, D.B. Williamsand J.I. Goldstein, Low temperature phase transformationsin the metallic phases of iron and stonyiron meteorites, Geochim. Cosmochim. Acta, 52 (1988) 617-626.
Materials Processing Technology ELSEVIER
Journal of Materials Processing Technology 57 (1996) 221-224
Phase investigation of an iron meteorite from Akyumak ilhan Aksoy a, Mehmet Ceylan b,*, Nejdet Kayali b a in6nii University, Science and Arts Faculty, Malatya, Turkey b Firat University, Science and Arts Faculty, Elazi~, Turkey Received 21 November 1994
Industrial summary
The phase of an iron meteorite which fell near Akyumak, East Anatolia, in 1981 have been investigated by optical and X-ray diffraction. Diffraction peaks of kamacite, teanite, plessite and cementite phases were separated and indexed by the related unit cell parameters of the phases. From the analysis of DSC and DTA curves, some phase transformation are known to have occurred during different heating regimes.
I. Introduction
An iron meteorite fell near Akyumak, Turkey in 1981, its mass being about 4 5 - 5 0 kg. A small fragment of the meteorite is in Elazi[g Military Museum, and the main mass of about 19 kg is in the Department of Geology, University of F/rat (Fig. 1). Certain physical and chemical properties of the meteorite were explored. Surface cavities and internal cavities were discovered and Widmanstatten patterns were discussed [1]. The average composition of the meteorite was given as 92.3 _+ 0.3 wt.% Fe and 7.7 +_ 0.1 wt.% Ni. Neuman bands were discovered [2]. In the present study, possible phases of the Akyumak meteorite have been examined by the optical microscope, X-ray diffraction and thermal analysis methods.
(a)
(h) Fig. 1. The main mass of the Akyumak meteorite. * Corresponding author. 0924-0136/96/$15.00 © 1996 Elsevier Science S.A. All rights reserved S S D I 0924-0136(95)02080-6
Fig. 2. Surface photographs of the meteorite, where K, T, P are kamacite, teanite and plessite phases and N relates to the highernickelized regions ( x 750).
). Aksoy et al./Journal of Materials Processing Technology 57 (1996) 221 224
222
3
11I
II
0
A 14.5
20
40
60
----~20
1/~5
20
40
60
--> 20 Fig. 4. Superposed diffractogram obtained from three diffractograms of the samples and selected peaks.
Fig. 3. X-ray diffractograms of the samples using a Mo target: I. outside powdered sample; II. mid-depth powdered sample; and III. core region powdered sample (background and smoothing elimination was used).
Table 1 Experimental data from Fig. 4
2. Experimental
No.
20 (o)
d (A)
T h e s a m p l e s u s e d in t h i s s t u d y w e r e o b t a i n e d b y c u t t i n g w i t h a steel s a w f r o m d i f f e r e n t r e g i o n s o f t h e Akyumak meteorite.
1 2 3
Two samples were prepared from the outside and the
4 5 6 7
16.40 18.25 20.49 25.75 28.07 28.99 31.02 31.62 35.63 36.65 38.55 41.24 46.53 49.05 51.14 55.61
2.487 2.236 1.994 1.592 1.462 1.417 1.326 1.302 1.159 1.128 1.074 1.007 0.898 0.854 0.822 0.760
i n s i d e b y c u t t i n g a slice w i t h a steel s a w , t h e s e s a m p l e s then being polished and etched. Surface photographs of these
samples were
taken
using
an
Olympus
BME
8
(Figs. 2(a) a n d (b)).
9
In addition to these, three samples were powdered from the outside, the mid-depth and the core of the meteorite, and X-ray diffractograms obtained by using
10 11 12 13
a Rigaku-Geigerflex diffractometer and
target
14
( F i g . 3). D i f f r a c t i o n p e a k s o f t h e p h a s e s w e r e d e t e r mined by the finger-print method.
15 16
a Mo
Table 2 Phase peaks and their related indices of the phases in the observed diffraction pattern of the iron meteorite from Akyumak Peak No.
20 (°)
Ni
1
16.40 18.25 20.49 25.75 28.07 28.99 31.02 31.62 35.63 36.65 38.55 41.24 46.53 49.05 51.14 55.61
011 . -012 --. ---. --223,014 --
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Kamacite ct-Fe
.
Teanite y-Fe
.
.
.
.
. -----
011 --002 .
.
. 022 -222 ---
.
Plessite (Ni, Fe) AsS
-012 112 --
022 013 --
--013
023 -114, 033 ---
023 004 114, 033 133 --
.
Cementite Fe3C2
.
.
.
-112 -.
Teanite 57.7% Fe 40.8 Ni, 0.5% P
122,003 123 004 223,014 024 124 134,015 333,115 125 33,035 335 444 155 346
003 211 203, 130 301 311 312 320 233, 205 330, 215 143, 402 333, 051 501 415, 154 434 524
223
i. Aksoy et al./ Journal of Materials Processing Technology 57 (1996) 221-224
't
'
t,~wl
-S.
.
.
.
.
"l'-g¢~~1163"3°6
I
too
200
.
.
~ ; o-c
.,1,
I
I
3o0
I
I
4oo
5oo
:~ [*C I
(a)
975.1~
1073.4 "C
- 245.1
I
7 50
..
I
,,,I
I
900
I
I
I
1200
1050
~['C l
(b)
Fig. 5. For the mid-section sample of the Akyumak meteorite: (a) DSC curve for 5 °C min-~ heating rate; (b) DTA curve for 10 °C rain-~ heating rate. In these curves, negative: and positive energies are absorbed and released by the sample, respectively, these absorbed and released energies corresponding to phase transformations.
224
1. Aksoy et al./Journal of Materials Processing Technology 57 (1996) 221-224
At the same time, about 30-50 mg pieces, cut from the mid-section of the meteoritic sample, were investigated using a Shimadzu differential scanning calorimeter (DSC-50) and differential thermal analyzer (DTA-50) see Figs. 5(a) and (b). The transformation energies required were determined from heating curves, as seen on the plots.
3. Results and discussion
As shown in Figs. 2(a) and (b), the surface photographs of the polished and etched meteorite samples show heavy dark, dark gray and bright gray regions, which means that the meteorite is a mixture of different phases. Some possible phases of the Akyumak meteorite were explored in [1,2] by the photographic method. In both of the papers [1,2] the authors reported that the main phases of the meteorite are kamacite, teanite and plessite. Here kamacite and teanite are in regular patterns, whilst plessite is a mixture of kamacite and teanite or a mixture of teanite and martensite. Some possible phases have been marked on the photographs of the surface (Figs. 2(a) and (b)), in which photographs, K denotes kamacite, T related to teanite and P means plessite, whilst N corresponds to the higher-nickelized regions. The three diffractograms in Fig. 3 were supposed for the sake of simplicity of phase analysis, the single superposed diffractogram displaying the possible phase peaks of the meteorite. This superposed diffractogram is presented in Fig. 4 and the related diffraction data given in Table 1. The possisble phase of an Iron-Nickel meteorite have been considered as: (1) Ni phase (a = 3.5238 b.c.c.); (2) e-Fe (kamacite) phase (a = 2.8664 A b.c.c.); (3) c(Fe (a = 2.8750 ~ b.c.c,); (4) ~-Fe (teanite) (a = 3.6468 A f.c.c.); (5) 57.7wt.%Fe 40.8wt.%Ni0.5wt.%P-others (teanite), ( a = 3 . 6 0 A cubic); (6) mixture of teanite and kamacite (Ni, Fe) AsS (plessite), ( a = 5.90A cubic); and (7) Fe3C2 (cementite), ( a = 4.5235 A, b = 5.0888 A, c = 6.7431 A orthorhombic).
By comparing the calculated 20 with the related unit cell parameters [4] and observed 20, the phase peaks were matched and indexed for every phase given above, these results being presented in Table 2. The maximum error of all indexed lines was considered as about the full width at half maximum of a diffraction peak. Because some diffraction peaks of the phases are very near to each other these peaks may be superposed. As shown in Table 2, the e'-Fe phase was not observed. In the diffraction pattern, all of the peaks contain cementite (except for the 16.40 ° peak) and plessite (except for the 16.40 ° and 18.25 ° peaks). In the pattern, the 16.40 ° peak is undoubtedly a Ni peak and the 18.25 ° peak is cementite. The other peaks of the ptterns are the superposed peaks of the phases. Some superlattices can occur in iron meteorites [5]. From the DSC curve, different kinds of phase transformations are known to have occurred in the sample at temperatures of 163.3 °C and 441.0 °C (Fig. 5(a)). During the transformation, the sample, about 50 rag, absorbed 25.85 mJ at 163.3 °C and released 407.27 mJ at 441.0 °C. From the DTA curve (Fig. 5(b)), the first phase change is seen in the temperature range 747.4-769.6 °C, the sample absorbing about 2806.22 mJ in this range. Furthermore, some phase changes occurred also at temperatures of 872.3, 978.8, 1073.4 and 1212 °C, the same sample absorbing about 105235.45 mJ in the temperature range 872.3-1212 °C. These results mean that the energies absorbed by this sample correspond to phase transformations during this heating regime. References
[1] M. Ceylan,J. Firat Univ., 2(2) (1987) 41-50. [2] K. ~olako~lu and M. Ceylan, Meteoritics, 23 (1988) 371-372. [3] E. Anders, Origin age and composition of meteorites, Space Sci. Rev., 3 (1964) 583-714. [4] Handbook of Chemistry and Physics, 63rd edn. CRC Press, Boca Raton, FL, 1982-83. pp. E. 193-197. [5] K.B. Reuter, D.B. Williamsand J.I. Goldstein, Low temperature phase transformationsin the metallic phases of iron and stonyiron meteorites, Geochim. Cosmochim. Acta, 52 (1988) 617-626.