- Email: [email protected]
Obtaining of bulk amorphous steel with low carbon content using industrial ferroalloys
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 19 (2019) 991–995
www.materialstoday.com/proceedings
BraMat 2019
Obtaining of bulk amorphous steel with low carbon content using industrial ferroalloys Cosmin Codreana, Dragoş Buzdugana,*, Carmen Oprişa, Petru Hididiş, Viorel-Aurel Şerbana a
University Politehnica Timisoara, no. 2 P-ta Victoriei, Timişoara 300006, Romania
Abstract Bulk amorphous steels (BASs) are a novel class of Fe-based bulk metallic glasses (BMGs), which have an attractive physical, thermal and mechanical properties that make them suitable for lots of industrial applications [1-3]. BAS synthesis requires special preparation conditions such as vacuum or controlled atmosphere and high-purity raw materials. These obtaining conditions increase the cost of these alloys and thus limit the development of new industrial applications. Multicomponent BAS rods with a diameter of 3 mm and 40 mm in length have been obtained by water-cooled copper mold casting in an air atmosphere, using industrial ferroalloys as raw materials. The obtained samples were structurally characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), while the mechanical properties were investigated by hardness and compression tests. Resulting structural aspects and mechanical properties are reported. © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 11th International Conference on Materials Science & Engineering, BraMat 2019 Keywords: bulk amorphous steels; industrial ferroalloys; GFA, hardness; compressive strength.
1. Introduction During the last two decades, Fe-based bulk metallic glasses have been extensively studied due to unique physical and mechanical properties such as high saturation magnetization, high permeability, and low coercivity, good corrosion resistance in aggressive solution, high fracture strength and high Vickers microhardness [1-3]. Among
* Corresponding author. Tel.: +040256403653; fax: +040256403523. E-mail address: [email protected] 2214-7853 © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 11th International Conference on Materials Science & Engineering, BraMat 2019
992
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
them, bulk amorphous steels (BASs) are of particular importance due to their relatively low cost and great potential for some industrial applications [4, 5]. Most of the bulk amorphous steels produced so far require special preparation conditions such as vacuum or controlled atmosphere and were synthesized using materials with the purity of higher than 99.5 wt% [4, 6-9]. Several bulk amorphous steel compositions have been reported, all with a high carbon content (over 10% at.). For example, BASs from the Fe–Mo(Ga)–(P,C,B,Si) system were synthesized with a thickness of up to 6 mm [1]. Subsequent, Lu et al. [10] has developed BASs from the Fe-Cr-Mo-C-B system, obtaining Fe-based BMGs with high glass-forming ability and critical thickness of the sample up to 12 mm. H. Fang et al. [11] and Shen et al. [12] improved the chemical compositions of the BASs by the addition of Mn, Y and Co respectively. They successfully increased the critical diameter of the BASs to 16mm, so that these Fe-Cr(Co)-Mo-Mn-C-B-Y BASs have become promising materials for making corrosion-resistant coatings, surgical instruments, medical implants, lighter automobiles, ship hulls or tall buildings [11, 12]. However, most of these amorphous steels are brittle, having negligible ductility [4] and they are still expensive by using high-purity raw materials, which limits their industrial applications. Therefore, researches have focused on obtaining bulk amorphous steels by air casting methods using industrial raw materials, with better ductility. Indeed, BAS can be fabricated by using industrial ferroalloys, significantly reducing the production cost [13]. Luo et al. [14] developed a BAS composition by rare earth microalloying of the Fe-Cr-Mo-C-B system which could be prepared in air. T. Xu et al. [15] succeeded to develop a novel Fe75Cr5(PBC)20 BAS using industrial ferroalloys such as Fe-C alloy, Fe-Cr alloy, Fe-P alloy, Fe-B alloy, without high-purity materials, by conventional copper mold casting, with a critical diameter of 2 mm. This success provides guidance to design new BASs with a combination of high GFA, good magnetic properties, excellent corrosion resistance, high fracture strength, high Vickers micro hardness and low cost. In this paper we have proposed the elaboration of BASs in the form of 3 mm diameter rods, using as raw materials as many ferroalloys. The following empirical rules were considered when establishing the chemical composition of master alloy to ensure a higher GFA [16]: (1) the alloy should contain minimum three components, from which two are metallic; (2) the metalloids content must be around 20 at.%; (3) the alloy must contain more elements with different atomic sizes; (4) the metallic elements must have large negative heats of mixing with the metalloids; (5) crystalline oxide inclusions must be carefully removed by neutralizing the oxygen. So the Fe-Cr-Mo(Y, Ga)-C-B-Si alloys family was chosen to satisfy these rules. The presence of chromium provides good corrosion resistance and good soft magnetic properties [2], and metalloids contribute to increase the GFA. Special attention was given to Ga and Y that can improve both GFA and the mechanical properties of the alloy [1, 6, 16]. 2. Experimental procedures Multicomponent Fe-based BASs were successfully synthesized by water-cooled copper mold casting in the form of rods using mostly ferroalloys and pure elements. One chemical composition was made only of ferroalloys and for another two were added Ga and Y to increase the GFA. Therefore, the chemical composition of the alloys used in this study are: Fe56Cr12Mo8Nb2C2B12Si8, Fe56Cr12Mo8Nb2C2B12Si6Ga2, Fe56Cr12Mo8Nb2C2B12Si6Y2 and Fe56Cr12Mo8Nb2C2B12Si4Y4. It was used as raw materials an ordinary steel (0.17 %C), Ferroalloys FeMo (55%Mo), FeNb (60 % Nb), FeB (23% B), Fe Si (75 %Si) and pure elements Cr, Ga, and Y. The rods obtained have a diameter of 3 mm and a length of 40 mm, as shown in Fig. 1. The obtained samples were structurally investigated by X-ray diffraction using an X'Pert³ Powder diffraction equipment with a Cu anode and wavelength of λ = 1.54 Å. The thermal stability was analyzed by differential scanning calorimetry (DSC) using a Netzsch STA 441 Jupiter. The investigations were performed on samples of about 20 mg under purified nitrogen gas with a heating rate of 10 K/min. The mechanical properties of the as-prepared rods with 3 mm in diameter and 10 mm in length were measured at the ambient temperature by a uniaxial compression test conducted using an LBG TC100 testing machine. The microhardness tests have been run on a Wolpert 402MVD Microhardness equipment. At least ten tests for each composition were conducted to ensure the reproducibility of the results.
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
993
Fig. 1. As cast rods.
3. Results and discussions The diffraction patterns for the as-cast rods are presented in Fig. 2. The diffraction pattern of the alloy which contains only ferroalloys without Ga or Y presents a monophasic crystalline structure based on a Feα solid solution. In case of the other alloys, the diffraction pattern contains only broad peaks characteristic to an amorphous structure.
Fig. 2. XRD patterns of the as-cast BASs.
The DSC curves are presented in Fig. 3. In case of the alloy free of Ga or Y, there is no presence of structural transformation in heating which confirms it’s crystalline structure. For the other alloys, exothermic peaks are observed which marks the crystallization of the amorphous phase. There were determined the glass transition temperatures Tg, the crystallization temperatures Tx and the ΔTx = Tx-Tg parameter which estimates the glass forming ability. The values are listed in table 1.
994
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
Fig. 3. DSC curves.
It was found that using only ferroalloys, although a monophasic structure is obtained, the crystallization process cannot be stopped. The presence of Ga and Y in the alloy chemical composition leads to a higher GFA by increasing the supercooled liquid region. This is due to an increasing the atomic packing density and by forming short-range compositional order in the liquid phase [1,16]. In the same time, a small addition of Y can inhibit the alloy components oxidation during the melting and casting processes which lead to suppression of heterogeneous nucleation [16]. It was noted a better thermal stability and GFA expressed as the supercooled liquid region for the alloy containing Ga (Tx = 692 °C and ΔTx=65). Higher content of Y improves the alloy thermal stability from 634 °C to 652 °C and has a higher GFA, ΔTx moves from 21 to 33. The mechanical tests were conducted only on the rods with the amorphous structure. The compressive stressstrain curves are shown in Fig. 4 and the values of microhardness and compressive strength are listed in table 1.
Fig. 4. Compressive stress-strain curves.
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
995
Table 1. Thermal and mechanical properties Alloy
Tg (⁰C)
Tx [⁰C]
ΔTx
HV0.1
Compressive strength σ [MPa]
Fe56Cr12Mo8Nb2C2B12Si6Ga2
627
692
65
530 ±5
2113 ±25
Fe56Cr12Mo8Nb2C2B12Si6Y2
613
634
21
498 ±4
1780 ±18
Fe56Cr12Mo8Nb2C2B12Si4Y4
619
652
33
550 ±5
2285 ±20
The compressive strain-stress curves show that the alloys containing Ga have a brittle behavior and the ones with Y presents a plastic deformation before fracture. It is noted that to the same amount of Ga and Y, the values of compressive strength and hardness are higher for alloys containing Ga (2113 MPa and 530 HV0.1) compared with the alloy containing Y (1780 MPa and 498 HV0.1). A higher Y content leads to better compressive strength and hardness (2285 MPa and 550 HV0.1) maintaining the plasticity behavior. Compared to other Fe-based BMGs with a similar Fe content having a compressive strength of 2900 – 3400 MPa [1], the elaborated BASs have slightly lower values of compressive strength, up to 2300 MPa but with a distinct plastic strain. By adding Y which ensures a higher GFA, is reduced the metalloids proportion and therefore is reduced the number of covalent bonding between metal-metalloid. These covalent bonding are responsible for brittleness and enhance a high compressive strength [1]. Therefore, a modified chemical composition that leads to a reduced number of covalent bonding can improve the plasticity of BASs but in the same time will reduce the values of compressive strength and hardness. 4. Conclusions Research carried out showed that using only ferroalloys in the elaboration of BAS could not stop the crystallization. A minimum addition of Ga or Y is needed to synthesize BAS rods with a diameter of 3 mm and 40 mm in length by water-cooled copper mold casting. The alloy containing two atomic percent Ga has a better glass forming ability than the alloy containing two atomic percent Y but is very brittle. Instead, the alloys containing Y enhance the plasticity but the values of compressive strength and hardness are below to the values reported in the literature. By adding four atomic percent of Y instead of Si, the GFA and the mechanical properties were improved. Acknowledgements This work was partially supported by research grant GNaC2018 - ARUT, no. 1358/01.02.2019, financed by Politehnica University of Timisoara. References [1] C Suryanarayana , A Inoue, Int. Mater. Rev. 58:3 (2013), 131-166. [2] M. Zhu, Yang FA, Z. Jian, L. Yao, C. Jin, J. Xu, R. Nan, F. Chang, Trans. Nonferrous Met. Soc. China 27(2017) 857−862. [3] T. Xu, Z. Jian, F. Chang, L. Zhuo, M. Shi, M. Zhu, J. Xu, Y. Liu, T. Zhang, J. Alloys. Compd. 699 (2017) 92-97. [4] M. Iqbal, J.I. Akhter, H.F. Zhang, Z.Q. Hu, J. Non. Cryst. Solids. 354 (2008) 3284–3290. [5] N. Nishiyama, K. Amiya, A. Inoue, Mater. Trans. 45 No. 4 (2004) 1245 – 1250. [6] M. Stoica, J. Eckert, S. Roth, A.R. Yavari, L. Schultz, , J. Alloys Compd. 434-435 (2007) 171-175. [7] J.F. Wang, R. Li, N.B. Hua, L. Huang, T. Zhang, Scr. Mater. 65 (2011) 536-539. [8] A. Makino, C.T. Chang, T. Hubota, A. Inoue, J. Alloys Compd. 483 (2009) 616-619. [9] M.J. Shi, S.J. Pang, T. Zhang, Intermetallics 61 (2015) 16-20. [10] Z.P. Lu, C.T. Liu, J.R. Thompson, W.D. Porter, Phys. Rev. Lett. 92 (2004), 245503–245511. [11] H. Fang, X. Hui, G. Chen, J. Alloys. Compd. 464 (2008) 292–295. [12] J. Shen, Q.J. Chen, J.F. Sun, H.B. Fan, G.Wang, Appl. Phys. Lett. 86 (2005), 151907–151911. [13] P.H. Tsai, A.C. Xiao, J.B. Li, J.S.C. Jang, J.P. Chu, J.C. Huang, J. Alloys. Compd. 586 (2014) 94–98. [14] C.Y. Luo, Y.H. Zhao, X.K. Xi, G. Wang, D.Q. Zhao, M.X. Pan, W.H. Wang, S.Z. Kou J. Non-Cryst. Solids. 352 (2006), 185–188. [15] T. Xu, Z. Jian, F. Chang, L. Zhuo, M. Shi, M. Zhu, J. Xu, Y. Liu, T. Zhang, J. Alloys. Compd. 699 (2017) 92-97. [16] D.S. Song, J.-H. Kim, E. Fleury, W.T. Kim, D.H. Kim J. Alloys. Compd. 389 (2005) 159–164.
ScienceDirect Materials Today: Proceedings 19 (2019) 991–995
www.materialstoday.com/proceedings
BraMat 2019
Obtaining of bulk amorphous steel with low carbon content using industrial ferroalloys Cosmin Codreana, Dragoş Buzdugana,*, Carmen Oprişa, Petru Hididiş, Viorel-Aurel Şerbana a
University Politehnica Timisoara, no. 2 P-ta Victoriei, Timişoara 300006, Romania
Abstract Bulk amorphous steels (BASs) are a novel class of Fe-based bulk metallic glasses (BMGs), which have an attractive physical, thermal and mechanical properties that make them suitable for lots of industrial applications [1-3]. BAS synthesis requires special preparation conditions such as vacuum or controlled atmosphere and high-purity raw materials. These obtaining conditions increase the cost of these alloys and thus limit the development of new industrial applications. Multicomponent BAS rods with a diameter of 3 mm and 40 mm in length have been obtained by water-cooled copper mold casting in an air atmosphere, using industrial ferroalloys as raw materials. The obtained samples were structurally characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), while the mechanical properties were investigated by hardness and compression tests. Resulting structural aspects and mechanical properties are reported. © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 11th International Conference on Materials Science & Engineering, BraMat 2019 Keywords: bulk amorphous steels; industrial ferroalloys; GFA, hardness; compressive strength.
1. Introduction During the last two decades, Fe-based bulk metallic glasses have been extensively studied due to unique physical and mechanical properties such as high saturation magnetization, high permeability, and low coercivity, good corrosion resistance in aggressive solution, high fracture strength and high Vickers microhardness [1-3]. Among
* Corresponding author. Tel.: +040256403653; fax: +040256403523. E-mail address: [email protected] 2214-7853 © 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 11th International Conference on Materials Science & Engineering, BraMat 2019
992
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
them, bulk amorphous steels (BASs) are of particular importance due to their relatively low cost and great potential for some industrial applications [4, 5]. Most of the bulk amorphous steels produced so far require special preparation conditions such as vacuum or controlled atmosphere and were synthesized using materials with the purity of higher than 99.5 wt% [4, 6-9]. Several bulk amorphous steel compositions have been reported, all with a high carbon content (over 10% at.). For example, BASs from the Fe–Mo(Ga)–(P,C,B,Si) system were synthesized with a thickness of up to 6 mm [1]. Subsequent, Lu et al. [10] has developed BASs from the Fe-Cr-Mo-C-B system, obtaining Fe-based BMGs with high glass-forming ability and critical thickness of the sample up to 12 mm. H. Fang et al. [11] and Shen et al. [12] improved the chemical compositions of the BASs by the addition of Mn, Y and Co respectively. They successfully increased the critical diameter of the BASs to 16mm, so that these Fe-Cr(Co)-Mo-Mn-C-B-Y BASs have become promising materials for making corrosion-resistant coatings, surgical instruments, medical implants, lighter automobiles, ship hulls or tall buildings [11, 12]. However, most of these amorphous steels are brittle, having negligible ductility [4] and they are still expensive by using high-purity raw materials, which limits their industrial applications. Therefore, researches have focused on obtaining bulk amorphous steels by air casting methods using industrial raw materials, with better ductility. Indeed, BAS can be fabricated by using industrial ferroalloys, significantly reducing the production cost [13]. Luo et al. [14] developed a BAS composition by rare earth microalloying of the Fe-Cr-Mo-C-B system which could be prepared in air. T. Xu et al. [15] succeeded to develop a novel Fe75Cr5(PBC)20 BAS using industrial ferroalloys such as Fe-C alloy, Fe-Cr alloy, Fe-P alloy, Fe-B alloy, without high-purity materials, by conventional copper mold casting, with a critical diameter of 2 mm. This success provides guidance to design new BASs with a combination of high GFA, good magnetic properties, excellent corrosion resistance, high fracture strength, high Vickers micro hardness and low cost. In this paper we have proposed the elaboration of BASs in the form of 3 mm diameter rods, using as raw materials as many ferroalloys. The following empirical rules were considered when establishing the chemical composition of master alloy to ensure a higher GFA [16]: (1) the alloy should contain minimum three components, from which two are metallic; (2) the metalloids content must be around 20 at.%; (3) the alloy must contain more elements with different atomic sizes; (4) the metallic elements must have large negative heats of mixing with the metalloids; (5) crystalline oxide inclusions must be carefully removed by neutralizing the oxygen. So the Fe-Cr-Mo(Y, Ga)-C-B-Si alloys family was chosen to satisfy these rules. The presence of chromium provides good corrosion resistance and good soft magnetic properties [2], and metalloids contribute to increase the GFA. Special attention was given to Ga and Y that can improve both GFA and the mechanical properties of the alloy [1, 6, 16]. 2. Experimental procedures Multicomponent Fe-based BASs were successfully synthesized by water-cooled copper mold casting in the form of rods using mostly ferroalloys and pure elements. One chemical composition was made only of ferroalloys and for another two were added Ga and Y to increase the GFA. Therefore, the chemical composition of the alloys used in this study are: Fe56Cr12Mo8Nb2C2B12Si8, Fe56Cr12Mo8Nb2C2B12Si6Ga2, Fe56Cr12Mo8Nb2C2B12Si6Y2 and Fe56Cr12Mo8Nb2C2B12Si4Y4. It was used as raw materials an ordinary steel (0.17 %C), Ferroalloys FeMo (55%Mo), FeNb (60 % Nb), FeB (23% B), Fe Si (75 %Si) and pure elements Cr, Ga, and Y. The rods obtained have a diameter of 3 mm and a length of 40 mm, as shown in Fig. 1. The obtained samples were structurally investigated by X-ray diffraction using an X'Pert³ Powder diffraction equipment with a Cu anode and wavelength of λ = 1.54 Å. The thermal stability was analyzed by differential scanning calorimetry (DSC) using a Netzsch STA 441 Jupiter. The investigations were performed on samples of about 20 mg under purified nitrogen gas with a heating rate of 10 K/min. The mechanical properties of the as-prepared rods with 3 mm in diameter and 10 mm in length were measured at the ambient temperature by a uniaxial compression test conducted using an LBG TC100 testing machine. The microhardness tests have been run on a Wolpert 402MVD Microhardness equipment. At least ten tests for each composition were conducted to ensure the reproducibility of the results.
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
993
Fig. 1. As cast rods.
3. Results and discussions The diffraction patterns for the as-cast rods are presented in Fig. 2. The diffraction pattern of the alloy which contains only ferroalloys without Ga or Y presents a monophasic crystalline structure based on a Feα solid solution. In case of the other alloys, the diffraction pattern contains only broad peaks characteristic to an amorphous structure.
Fig. 2. XRD patterns of the as-cast BASs.
The DSC curves are presented in Fig. 3. In case of the alloy free of Ga or Y, there is no presence of structural transformation in heating which confirms it’s crystalline structure. For the other alloys, exothermic peaks are observed which marks the crystallization of the amorphous phase. There were determined the glass transition temperatures Tg, the crystallization temperatures Tx and the ΔTx = Tx-Tg parameter which estimates the glass forming ability. The values are listed in table 1.
994
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
Fig. 3. DSC curves.
It was found that using only ferroalloys, although a monophasic structure is obtained, the crystallization process cannot be stopped. The presence of Ga and Y in the alloy chemical composition leads to a higher GFA by increasing the supercooled liquid region. This is due to an increasing the atomic packing density and by forming short-range compositional order in the liquid phase [1,16]. In the same time, a small addition of Y can inhibit the alloy components oxidation during the melting and casting processes which lead to suppression of heterogeneous nucleation [16]. It was noted a better thermal stability and GFA expressed as the supercooled liquid region for the alloy containing Ga (Tx = 692 °C and ΔTx=65). Higher content of Y improves the alloy thermal stability from 634 °C to 652 °C and has a higher GFA, ΔTx moves from 21 to 33. The mechanical tests were conducted only on the rods with the amorphous structure. The compressive stressstrain curves are shown in Fig. 4 and the values of microhardness and compressive strength are listed in table 1.
Fig. 4. Compressive stress-strain curves.
C. Codrean et al. / Materials Today: Proceedings 19 (2019) 991–995
995
Table 1. Thermal and mechanical properties Alloy
Tg (⁰C)
Tx [⁰C]
ΔTx
HV0.1
Compressive strength σ [MPa]
Fe56Cr12Mo8Nb2C2B12Si6Ga2
627
692
65
530 ±5
2113 ±25
Fe56Cr12Mo8Nb2C2B12Si6Y2
613
634
21
498 ±4
1780 ±18
Fe56Cr12Mo8Nb2C2B12Si4Y4
619
652
33
550 ±5
2285 ±20
The compressive strain-stress curves show that the alloys containing Ga have a brittle behavior and the ones with Y presents a plastic deformation before fracture. It is noted that to the same amount of Ga and Y, the values of compressive strength and hardness are higher for alloys containing Ga (2113 MPa and 530 HV0.1) compared with the alloy containing Y (1780 MPa and 498 HV0.1). A higher Y content leads to better compressive strength and hardness (2285 MPa and 550 HV0.1) maintaining the plasticity behavior. Compared to other Fe-based BMGs with a similar Fe content having a compressive strength of 2900 – 3400 MPa [1], the elaborated BASs have slightly lower values of compressive strength, up to 2300 MPa but with a distinct plastic strain. By adding Y which ensures a higher GFA, is reduced the metalloids proportion and therefore is reduced the number of covalent bonding between metal-metalloid. These covalent bonding are responsible for brittleness and enhance a high compressive strength [1]. Therefore, a modified chemical composition that leads to a reduced number of covalent bonding can improve the plasticity of BASs but in the same time will reduce the values of compressive strength and hardness. 4. Conclusions Research carried out showed that using only ferroalloys in the elaboration of BAS could not stop the crystallization. A minimum addition of Ga or Y is needed to synthesize BAS rods with a diameter of 3 mm and 40 mm in length by water-cooled copper mold casting. The alloy containing two atomic percent Ga has a better glass forming ability than the alloy containing two atomic percent Y but is very brittle. Instead, the alloys containing Y enhance the plasticity but the values of compressive strength and hardness are below to the values reported in the literature. By adding four atomic percent of Y instead of Si, the GFA and the mechanical properties were improved. Acknowledgements This work was partially supported by research grant GNaC2018 - ARUT, no. 1358/01.02.2019, financed by Politehnica University of Timisoara. References [1] C Suryanarayana , A Inoue, Int. Mater. Rev. 58:3 (2013), 131-166. [2] M. Zhu, Yang FA, Z. Jian, L. Yao, C. Jin, J. Xu, R. Nan, F. Chang, Trans. Nonferrous Met. Soc. China 27(2017) 857−862. [3] T. Xu, Z. Jian, F. Chang, L. Zhuo, M. Shi, M. Zhu, J. Xu, Y. Liu, T. Zhang, J. Alloys. Compd. 699 (2017) 92-97. [4] M. Iqbal, J.I. Akhter, H.F. Zhang, Z.Q. Hu, J. Non. Cryst. Solids. 354 (2008) 3284–3290. [5] N. Nishiyama, K. Amiya, A. Inoue, Mater. Trans. 45 No. 4 (2004) 1245 – 1250. [6] M. Stoica, J. Eckert, S. Roth, A.R. Yavari, L. Schultz, , J. Alloys Compd. 434-435 (2007) 171-175. [7] J.F. Wang, R. Li, N.B. Hua, L. Huang, T. Zhang, Scr. Mater. 65 (2011) 536-539. [8] A. Makino, C.T. Chang, T. Hubota, A. Inoue, J. Alloys Compd. 483 (2009) 616-619. [9] M.J. Shi, S.J. Pang, T. Zhang, Intermetallics 61 (2015) 16-20. [10] Z.P. Lu, C.T. Liu, J.R. Thompson, W.D. Porter, Phys. Rev. Lett. 92 (2004), 245503–245511. [11] H. Fang, X. Hui, G. Chen, J. Alloys. Compd. 464 (2008) 292–295. [12] J. Shen, Q.J. Chen, J.F. Sun, H.B. Fan, G.Wang, Appl. Phys. Lett. 86 (2005), 151907–151911. [13] P.H. Tsai, A.C. Xiao, J.B. Li, J.S.C. Jang, J.P. Chu, J.C. Huang, J. Alloys. Compd. 586 (2014) 94–98. [14] C.Y. Luo, Y.H. Zhao, X.K. Xi, G. Wang, D.Q. Zhao, M.X. Pan, W.H. Wang, S.Z. Kou J. Non-Cryst. Solids. 352 (2006), 185–188. [15] T. Xu, Z. Jian, F. Chang, L. Zhuo, M. Shi, M. Zhu, J. Xu, Y. Liu, T. Zhang, J. Alloys. Compd. 699 (2017) 92-97. [16] D.S. Song, J.-H. Kim, E. Fleury, W.T. Kim, D.H. Kim J. Alloys. Compd. 389 (2005) 159–164.