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Atomic arrangement in a Fe78.5Ni1.0Mo0.5Si6.0B14.0 amorphous alloy at different temperatures
Journal of Alloys and Compounds 383 (2004) 334–337
Atomic arrangement in a Fe78.5Ni1.0 Mo0.5Si6.0 B14.0 amorphous alloy at different temperatures S.I. Mudry a , B.Ya. Kotur b,∗ , L.M. Bednarska b , Yu.O. Kulyk a a b
Faculty of Physics, Ivan Franko National University of Lviv, Kyryla and Mefodiya Street 8, 79005 Lviv, Ukraine Faculty of Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodiya Street 6, 79005 Lviv, Ukraine
Abstract The temperature dependence of the short range order in the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloys has been studied by means of X-ray diffraction (XRD). Total structure factors and binary correlation functions at different temperatures are presented. It is shown that the temperature dependence of the structure at heating is influenced by both topological and chemical disorder. ␣-Fe(Si) crystals and Fe2 B-like atomic groups are the first products of the crystallization process. © 2004 Elsevier B.V. All rights reserved. Keywords: Amorphous metallic alloys; Structure factor; Chemical ordering; Crystallization process
1. Introduction
2. Experimental
The structure of amorphous metallic alloys (AMA) was investigated preferentially at room temperatures. The temperature dependence of the occurring structure of AMA reveals many physical characteristics such as the phase transition point, thermal expansion coefficient, Debye temperature and others. In topologically disordered systems, the structural changes with temperature display coexistence of different structural units, their birth, growth and disappearance. Thermal stability of the amorphous phase is also connected with the stability of different structural units. The temperature dependence of structural changes of AMA is also important due to growing interest in the production of nanomaterials. Thermal annealing of AMA at defined temperatures is the way to directly obtain nanocrystalline phases [1–4]. Besides, some amorphous structural units of nanoscale size occur in quenched alloys. The aim of this work was to study the structure of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy at different temperatures. This alloy has a practical interest due to its magnetic properties.
A Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy was prepared by melt spinning from the liquid state [5]. Ribbons of 30 m thickness were studied by X-ray scattering. A sample was placed into the chamber attached to the X-ray powder diffractometer (Co K␣-radiation, LiF monochromator). This chamber was filled with pure helium in order to avoid oxidation of the sample during the experiment. The studies were carried out in the temperature range 293–1173 K with a 0.1 step within the 2θ range from 10◦ to 140◦ . The scattering intensity values I as a function of scattering angles 2θ were recorded by means of a PC controlled electronic system. The corrections on absorption, polarization and incoherent scattering were applied [6]. The intensity function was used for calculation of structure factors (SFs). In order to calculate the binary correlation functions from SF integral a Fourier transformation was used:
∗
Corresponding author. E-mail address: [email protected] (B.Ya. Kotur).
0925-8388/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2004.04.043
g(r) = 1 +
1 2π2 ρ0 r
∞
q[a(q) − 1]sin(qr)dq,
0
where ρ0 is the mean atomic density; q = vector and r the interatomic distance.
4π sinθ λ
the wave
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337
335
3. Results and discussion
3 2 1
S(q)
5
0
4
0
3
0
2
0
1
0 1
2
3
4
5
6
0 -1
(a)
q, A
4 3 2 1
5
0
4
0
3
0
2
0
1
0
2 (b)
3
6
0
S(q)
In order to analyze the experimental data of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy, the comparison with the corresponding data for the Fe80.0 Si6.0 B14.0 alloy should be considered. The latter alloy was studied by X-ray diffraction (XRD) and interpretation of results was carried out in frames of the microscopic inhomogeneous model [7]. It is noted that ␣-Fe(Si), ␥-Fe(Si), and Fe3 B phases are the main structural units of this alloy. We also have studied the structure of the Fe80 Si6 B14 amorphous alloy. Its SF shows the first peak position at 3.14 Å−1 (Fig. 1, curve 1). The addition of Ni and Mo atoms results in the appearance of a principal peak fine structure (Fig. 1, curve 2). This peak can be presented as a superposition of two subpeaks with different positions. The left one corresponds to an ␣-Fe(Si)-based structure (3.09 Å−1 ). The second one is located close to the peak position of the amorphous alloy Fe80.0 Si6.0 B14.0 (3.17 Å−1 ). This peak is partly attributed to chemically ordered Fe3 B-groups. Thus, the addition of Ni and Mo atoms promotes some rearrangement of the ␣-Fe(Si) atomic groups with an increase of the most probable interatomic distance. At the same time the formation of a more inhomogeneous structure accompanies this rearrangement. The structure factors for the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at different temperatures are presented in Fig. 2. As can be seen, the profile of SF is typical for metallic amorphous alloys, especially the splitting of the second peak is pronounced. With the increase of temperature the height of the peaks reduces, indicating topological disorder. As it is known [8], the half width of the principal peak is connected with the size of ordered groups of atoms. From the temperature dependence of this parameter follows a decrease in size of ordered atomic groups with heating of the alloy. The chemical short range order influences significantly the atomic arrangement and its temperature dependence. In mul-
3
4 q, A
5
6
0 -1
Fig. 2. Structure factors for the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; 5: 673 K.
2
S(q)
1 2
0 0
1 0 0 1
2
3
4
5
6
0 -1
q,A
Fig. 1. Structure factors for the amorphous alloys Fe80.0 Si6.0 B14.0 (1) and Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 (2).
ticomponent disordered systems there is no absolutely random distribution of different kinds of atoms. Deviation from random atomic distribution is a result of chemical ordering which can be observed experimentally. The comparison of the principal peak position for the investigated AMA with the corresponding one for amorphous Fe (2.98 Å), obtained by deposition of a gaseous phase on substrate, allows to conclude that structuring of this element is dominant in formation of short range order [9]. On the other hand, B atoms attempt to interact with Fe atoms, forming the chemically ordered (associated) groups of atoms. This tendency was evidently observed in Fe85 B15 AMA [7].
336
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337 o -1
q1,A
3
3.14
2 1
3.12
6
S(q)
0
5
0
3.10
4
0
3.08
3 0
2
0 0 2.5
3.5
500
600
700
4.0 Fig. 4. Temperature dependence at q1 parameters of SF for the amorphous alloy Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 .
0 -1
q, A
3 2 1 5 0 S(q)
400
T, K
3.0
4
4 0 3 0 2 0 1 0
(b)
300
1
(a)
2.5
3.06
3.0
3.5
4.0
0 -1
q, A
Fig. 3. First peak profile of SF of the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; and 5: 673 K.
The comparison of the most intensive peak positions for the metastable chemical compound Fe3 B (q1 = 2.73 Å) and for stable Fe2 B (q1 = 3.15 Å) forming in Fe85 B15 AMA with SF of Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 AMA at different temperatures, which are presented in Fig. 3, shows that these compounds occur also in the latter one. Particularly, principal peaks of structure factors show the asymmetry with a more pronounced flat region on their right hand branches. It is reasonable to suppose that this asymmetry is caused by chemical ordering.
The analysis of SF allows noting that their principal peak positions are somewhat higher than expected for silicon solution in pure iron. Taking this fact into account as well as the influence of chemical ordering on the structure, we can assume that the atomic arrangement in this alloy can be presented as a disordered iron based matrix, where chemically ordered Fe3 B clusters are randomly distributed. It can be seen from the temperature dependence of SF, presented in Fig. 2 that these features exist over the temperature range studied up to the crystallization point [10]. An almost unchangeable value of the first peak position is observed in the temperature range from room temperature to 600 K. Such behavior can be explained by the existence of two factors (1) temperature expansion and (2) relaxation process. The first of them leads to a shift of the principal peak to lower q-values corresponding to an increase of the interatomic distance in real space. The second one is connected with diso
d, A 1.455 1.450 1.445 1.440 1.435 400
500
600 700 T, K
800
900
Fig. 5. Temperature dependence of interplanar distance d(1 1 0) for the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy.
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337
g(r)
2 1
6
0
5
0
4
0
3
0
2
0
1
0 4
8
12
16
0
r, A
(a)
337
Hence, the composition of initial ␣-Fe(Si) crystals can be different from the composition of the amorphous matrix. The second reason for this shift is attributed to thermal expansion. The increase of the interplanar distance d(1 1 0) with increasing temperature is caused by the expansion of ␣-Fe(Si) and more intensive diffusive processes. These facts were confirmed by the temperature dependence of the interplanar distance which is presented in Fig. 5. Binary correlation functions of AMA at different temperatures are presented in Fig. 6. The most important feature of these curves is a change of the second maximum profile, especially of its right hand side. The splitting, observed at lower temperatures disappears with heating. This feature is most sensitive to temperature and indicates some rearrangement of atoms within few coordination spheres. This rearrangement is evidence of transition to more equilibrium state in amorphous phase. It should be noted also that upon heating to 700 K an additional peak is observed at 2θ = 36.8◦ .
g(r)
2 1
5
4. Conclusions
0
4
0
3
0
2
0
1
On the basis of X-ray diffraction studies it is possible to conclude that the atomic arrangement of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy preferably consists of an ␣-Fe(Si) matrix, where chemically ordered Fe–Si, and Fe–B heterocoordinated atomic groups are randomly distributed. The crystallization process begins at 673 K and the initial ␣-Fe(Si) crystals are the first products of it. Temperature dependence of most probable interatomic distances confirm these structural changes upon heating and crystallization.
0 0 4
8
12
16
0
(b)
r, A
Fig. 6. Binary correlation functions of the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; and 5: 673 K.
appearing free volume. If the temperature is higher than 600 K a significant shift in the first peak position is observed (Fig. 4). Such behavior indicates that the relaxation process is completed and thermal expansion becomes dominant in the temperature dependence of structure factors. Complete crystallization of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy is observed at 673 K by formation of initial ␣-Fe(Si) crystals indicated by the appearance of a sharp (1 1 0) peak in the X-ray diffraction pattern. The position of this peak (3.07 Å−1 ) is slightly shifted in respect to the maximum position of the amorphous phase (3.09 Å−1 ).
References [1] T. Kulik, J. Non-Crystalline Solids 287 (2001) 145–161. [2] W.J. Botta, D. Negri, A.R. Yavari, J. Non-Crystalline Solids 247 (1999) 19–25. [3] S. Xiangcheng, A. Cabral-Prieto, M.J. Yacaman, Physica B 291 (2000) 173–179. [4] V.V. Maslov, V.E. Nosenko, L.A. Taranenko, A.P. Brovko, Fizika Metallov i Metalovedenije 91 (2001) 47–55 (in Russian). [5] H. Jones, Rapid Solidification of Metals and Alloys, Monograf No. 8, Institute of Metallurgy, London, England, 1982, p. 536. [6] L.I. Mirkin, Handbook on X-Ray Analysis, Moscow, Physics and Mathematics Publication, 1961, 863 (in Russian). [7] A. Shpak, Yu. Kunitsky, V. Lysov, Cluster and Nanostructural Materials, Kyiv, Akademperiodyka, 2002, 540 (in Russian). [8] A.V. Romanova, Metallofizika 5 (1983) 49–56 (in Russian). [9] T. Ishikawa, Phys. Status Sol. 19 (1973) 707–714. [10] M. Zacharenko, O. Brud’ko, M. Babich, V. Nosenko, T. Tsvetkova, O. Stelmakh, J. Magn. Magn. Mater. 215–216 (2000) 313– 315.
Atomic arrangement in a Fe78.5Ni1.0 Mo0.5Si6.0 B14.0 amorphous alloy at different temperatures S.I. Mudry a , B.Ya. Kotur b,∗ , L.M. Bednarska b , Yu.O. Kulyk a a b
Faculty of Physics, Ivan Franko National University of Lviv, Kyryla and Mefodiya Street 8, 79005 Lviv, Ukraine Faculty of Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodiya Street 6, 79005 Lviv, Ukraine
Abstract The temperature dependence of the short range order in the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloys has been studied by means of X-ray diffraction (XRD). Total structure factors and binary correlation functions at different temperatures are presented. It is shown that the temperature dependence of the structure at heating is influenced by both topological and chemical disorder. ␣-Fe(Si) crystals and Fe2 B-like atomic groups are the first products of the crystallization process. © 2004 Elsevier B.V. All rights reserved. Keywords: Amorphous metallic alloys; Structure factor; Chemical ordering; Crystallization process
1. Introduction
2. Experimental
The structure of amorphous metallic alloys (AMA) was investigated preferentially at room temperatures. The temperature dependence of the occurring structure of AMA reveals many physical characteristics such as the phase transition point, thermal expansion coefficient, Debye temperature and others. In topologically disordered systems, the structural changes with temperature display coexistence of different structural units, their birth, growth and disappearance. Thermal stability of the amorphous phase is also connected with the stability of different structural units. The temperature dependence of structural changes of AMA is also important due to growing interest in the production of nanomaterials. Thermal annealing of AMA at defined temperatures is the way to directly obtain nanocrystalline phases [1–4]. Besides, some amorphous structural units of nanoscale size occur in quenched alloys. The aim of this work was to study the structure of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy at different temperatures. This alloy has a practical interest due to its magnetic properties.
A Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy was prepared by melt spinning from the liquid state [5]. Ribbons of 30 m thickness were studied by X-ray scattering. A sample was placed into the chamber attached to the X-ray powder diffractometer (Co K␣-radiation, LiF monochromator). This chamber was filled with pure helium in order to avoid oxidation of the sample during the experiment. The studies were carried out in the temperature range 293–1173 K with a 0.1 step within the 2θ range from 10◦ to 140◦ . The scattering intensity values I as a function of scattering angles 2θ were recorded by means of a PC controlled electronic system. The corrections on absorption, polarization and incoherent scattering were applied [6]. The intensity function was used for calculation of structure factors (SFs). In order to calculate the binary correlation functions from SF integral a Fourier transformation was used:
∗
Corresponding author. E-mail address: [email protected] (B.Ya. Kotur).
0925-8388/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2004.04.043
g(r) = 1 +
1 2π2 ρ0 r
∞
q[a(q) − 1]sin(qr)dq,
0
where ρ0 is the mean atomic density; q = vector and r the interatomic distance.
4π sinθ λ
the wave
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337
335
3. Results and discussion
3 2 1
S(q)
5
0
4
0
3
0
2
0
1
0 1
2
3
4
5
6
0 -1
(a)
q, A
4 3 2 1
5
0
4
0
3
0
2
0
1
0
2 (b)
3
6
0
S(q)
In order to analyze the experimental data of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy, the comparison with the corresponding data for the Fe80.0 Si6.0 B14.0 alloy should be considered. The latter alloy was studied by X-ray diffraction (XRD) and interpretation of results was carried out in frames of the microscopic inhomogeneous model [7]. It is noted that ␣-Fe(Si), ␥-Fe(Si), and Fe3 B phases are the main structural units of this alloy. We also have studied the structure of the Fe80 Si6 B14 amorphous alloy. Its SF shows the first peak position at 3.14 Å−1 (Fig. 1, curve 1). The addition of Ni and Mo atoms results in the appearance of a principal peak fine structure (Fig. 1, curve 2). This peak can be presented as a superposition of two subpeaks with different positions. The left one corresponds to an ␣-Fe(Si)-based structure (3.09 Å−1 ). The second one is located close to the peak position of the amorphous alloy Fe80.0 Si6.0 B14.0 (3.17 Å−1 ). This peak is partly attributed to chemically ordered Fe3 B-groups. Thus, the addition of Ni and Mo atoms promotes some rearrangement of the ␣-Fe(Si) atomic groups with an increase of the most probable interatomic distance. At the same time the formation of a more inhomogeneous structure accompanies this rearrangement. The structure factors for the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at different temperatures are presented in Fig. 2. As can be seen, the profile of SF is typical for metallic amorphous alloys, especially the splitting of the second peak is pronounced. With the increase of temperature the height of the peaks reduces, indicating topological disorder. As it is known [8], the half width of the principal peak is connected with the size of ordered groups of atoms. From the temperature dependence of this parameter follows a decrease in size of ordered atomic groups with heating of the alloy. The chemical short range order influences significantly the atomic arrangement and its temperature dependence. In mul-
3
4 q, A
5
6
0 -1
Fig. 2. Structure factors for the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; 5: 673 K.
2
S(q)
1 2
0 0
1 0 0 1
2
3
4
5
6
0 -1
q,A
Fig. 1. Structure factors for the amorphous alloys Fe80.0 Si6.0 B14.0 (1) and Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 (2).
ticomponent disordered systems there is no absolutely random distribution of different kinds of atoms. Deviation from random atomic distribution is a result of chemical ordering which can be observed experimentally. The comparison of the principal peak position for the investigated AMA with the corresponding one for amorphous Fe (2.98 Å), obtained by deposition of a gaseous phase on substrate, allows to conclude that structuring of this element is dominant in formation of short range order [9]. On the other hand, B atoms attempt to interact with Fe atoms, forming the chemically ordered (associated) groups of atoms. This tendency was evidently observed in Fe85 B15 AMA [7].
336
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337 o -1
q1,A
3
3.14
2 1
3.12
6
S(q)
0
5
0
3.10
4
0
3.08
3 0
2
0 0 2.5
3.5
500
600
700
4.0 Fig. 4. Temperature dependence at q1 parameters of SF for the amorphous alloy Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 .
0 -1
q, A
3 2 1 5 0 S(q)
400
T, K
3.0
4
4 0 3 0 2 0 1 0
(b)
300
1
(a)
2.5
3.06
3.0
3.5
4.0
0 -1
q, A
Fig. 3. First peak profile of SF of the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; and 5: 673 K.
The comparison of the most intensive peak positions for the metastable chemical compound Fe3 B (q1 = 2.73 Å) and for stable Fe2 B (q1 = 3.15 Å) forming in Fe85 B15 AMA with SF of Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 AMA at different temperatures, which are presented in Fig. 3, shows that these compounds occur also in the latter one. Particularly, principal peaks of structure factors show the asymmetry with a more pronounced flat region on their right hand branches. It is reasonable to suppose that this asymmetry is caused by chemical ordering.
The analysis of SF allows noting that their principal peak positions are somewhat higher than expected for silicon solution in pure iron. Taking this fact into account as well as the influence of chemical ordering on the structure, we can assume that the atomic arrangement in this alloy can be presented as a disordered iron based matrix, where chemically ordered Fe3 B clusters are randomly distributed. It can be seen from the temperature dependence of SF, presented in Fig. 2 that these features exist over the temperature range studied up to the crystallization point [10]. An almost unchangeable value of the first peak position is observed in the temperature range from room temperature to 600 K. Such behavior can be explained by the existence of two factors (1) temperature expansion and (2) relaxation process. The first of them leads to a shift of the principal peak to lower q-values corresponding to an increase of the interatomic distance in real space. The second one is connected with diso
d, A 1.455 1.450 1.445 1.440 1.435 400
500
600 700 T, K
800
900
Fig. 5. Temperature dependence of interplanar distance d(1 1 0) for the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy.
S.I. Mudry et al. / Journal of Alloys and Compounds 383 (2004) 334–337
g(r)
2 1
6
0
5
0
4
0
3
0
2
0
1
0 4
8
12
16
0
r, A
(a)
337
Hence, the composition of initial ␣-Fe(Si) crystals can be different from the composition of the amorphous matrix. The second reason for this shift is attributed to thermal expansion. The increase of the interplanar distance d(1 1 0) with increasing temperature is caused by the expansion of ␣-Fe(Si) and more intensive diffusive processes. These facts were confirmed by the temperature dependence of the interplanar distance which is presented in Fig. 5. Binary correlation functions of AMA at different temperatures are presented in Fig. 6. The most important feature of these curves is a change of the second maximum profile, especially of its right hand side. The splitting, observed at lower temperatures disappears with heating. This feature is most sensitive to temperature and indicates some rearrangement of atoms within few coordination spheres. This rearrangement is evidence of transition to more equilibrium state in amorphous phase. It should be noted also that upon heating to 700 K an additional peak is observed at 2θ = 36.8◦ .
g(r)
2 1
5
4. Conclusions
0
4
0
3
0
2
0
1
On the basis of X-ray diffraction studies it is possible to conclude that the atomic arrangement of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy preferably consists of an ␣-Fe(Si) matrix, where chemically ordered Fe–Si, and Fe–B heterocoordinated atomic groups are randomly distributed. The crystallization process begins at 673 K and the initial ␣-Fe(Si) crystals are the first products of it. Temperature dependence of most probable interatomic distances confirm these structural changes upon heating and crystallization.
0 0 4
8
12
16
0
(b)
r, A
Fig. 6. Binary correlation functions of the amorphous Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 alloy at temperatures (a) 1: 293 K; 2: 323 K; 3: 373 K; 4: 423 K; 5: 473 K; 6: 523 K and (b) 1: 573 K; 2: 598 K; 3: 623 K; 4: 648 K; and 5: 673 K.
appearing free volume. If the temperature is higher than 600 K a significant shift in the first peak position is observed (Fig. 4). Such behavior indicates that the relaxation process is completed and thermal expansion becomes dominant in the temperature dependence of structure factors. Complete crystallization of the Fe78.5 Ni1.0 Mo0.5 Si6.0 B14.0 amorphous alloy is observed at 673 K by formation of initial ␣-Fe(Si) crystals indicated by the appearance of a sharp (1 1 0) peak in the X-ray diffraction pattern. The position of this peak (3.07 Å−1 ) is slightly shifted in respect to the maximum position of the amorphous phase (3.09 Å−1 ).
References [1] T. Kulik, J. Non-Crystalline Solids 287 (2001) 145–161. [2] W.J. Botta, D. Negri, A.R. Yavari, J. Non-Crystalline Solids 247 (1999) 19–25. [3] S. Xiangcheng, A. Cabral-Prieto, M.J. Yacaman, Physica B 291 (2000) 173–179. [4] V.V. Maslov, V.E. Nosenko, L.A. Taranenko, A.P. Brovko, Fizika Metallov i Metalovedenije 91 (2001) 47–55 (in Russian). [5] H. Jones, Rapid Solidification of Metals and Alloys, Monograf No. 8, Institute of Metallurgy, London, England, 1982, p. 536. [6] L.I. Mirkin, Handbook on X-Ray Analysis, Moscow, Physics and Mathematics Publication, 1961, 863 (in Russian). [7] A. Shpak, Yu. Kunitsky, V. Lysov, Cluster and Nanostructural Materials, Kyiv, Akademperiodyka, 2002, 540 (in Russian). [8] A.V. Romanova, Metallofizika 5 (1983) 49–56 (in Russian). [9] T. Ishikawa, Phys. Status Sol. 19 (1973) 707–714. [10] M. Zacharenko, O. Brud’ko, M. Babich, V. Nosenko, T. Tsvetkova, O. Stelmakh, J. Magn. Magn. Mater. 215–216 (2000) 313– 315.