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Effect of high-pressure torsion on the tendency to plastic flow in bulk amorphous alloys based on Zr
Materials Letters 256 (2019) 126631
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Effect of high-pressure torsion on the tendency to plastic flow in bulk amorphous alloys based on Zr A.M. Glezer a,⇑, D.V. Louzguine-Luzgin b,c, I.A. Khriplivets a, R.V. Sundeev d, D.V. Gunderov e, A.I. Bazlov a, Yu.S. Pogozhev a a
National University of Science and Technology «MISIS», 119049, Leninskiy pr. 4, Moscow, Russia WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577, Japan MathAM-OIL, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 980-8577, Japan d ‘‘MIREA - Russian Technological University”, 119454, Vernadskogo pr. 78, Moscow, Russia e Institute of Molecule and Crystal Physics of Ufa Federal Research Centre RAS, 450075, Prospekt Oktyabrya 151, Ufa, Russia b c
a r t i c l e
i n f o
Article history: Received 1 September 2019 Accepted 4 September 2019 Available online 5 September 2019 Keywords: Severe plastic deformation High-pressure torsion Bulk amorphous alloys Pileup Microhardness
a b s t r a c t The effect of the degree of room-temperature plastic deformation by high-pressure torsion on the tendency to plastic flow in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 and Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloys has been studied by Vickers microindentation and precision measurements of the relative height of the ‘‘pileup” at the base of the indent. Three stages of the dependence of plasticity on the number of full revolutions of the moving anvil upon high pressure torsion of the alloys have been established. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction One of the unique properties of amorphous alloys is their ability to plastic flow [1–3]. Deformation generally occurs by strongly localized shear bands 20–30 nm thick [3,4]. It has been established that the preliminary deformation of Fe-, Co-, and Zr-based amorphous alloys can either increase or decrease their strength [5]. In addition, it was found [6] that the preliminary deformation of the Zr55Cu30Al10Ni5 amorphous alloy increases its plasticity. In recent years, methods of severe plastic deformation (SPD) have been intensely developed [7,8]. In the case where SPD is applied to amorphous alloys (for example, by high pressure torsion (HPT)), the plastic flow is accompanied by a noticeable increase in the bulk density of shear bands and the delocalization of plastic deformation [9]. The measurement of the mechanical properties of amorphous alloys after HPT revealed both a noticeable decrease (the Zr44Ti11Cu10Ni10Be25 alloy) [10] or an increase (the Zr50.7Cu28Ni9Al12.3 alloy) in strength and microhardness [11]. In some works, the plasticity of amorphous alloys was quite unexpectedly observed to be
⇑ Corresponding author. E-mail address: [email protected] (A.M. Glezer). https://doi.org/10.1016/j.matlet.2019.126631 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
substantially increased after HPT [12,13]. The increase in plasticity of amorphous alloys after HPT remains a controversial and insufficiently established phenomenon. In this paper, we attempted to evaluate the effect of HPT on the plasticity of bulk amorphous Zr-based alloys by the microindentation method. 2. Experimental The ingots of the Zr60Cu18.5Nb2Ni7.5Al10Ti2 (1) b Zr52.5Cu17.9Ni14.6Al10Ti5 (2) Zr-based alloys (the compositions are given in nominal atomic percents) were prepared by arc melting of the mixtures of the pure (99.9 mass%) metals in an argon atmosphere. Bulk rod samples of 6 mm in diameter were prepared from the ingots by induction melting and the copper-mold casting technique. Disks 0.75 mm thick manufactured from the rods were subjected to HPT to different numbers of full revolutions of the movable anvil (n = 16) at a quasi-hydrostatic pressure of 6 GPa and at a rotation speed of the movable anvil of 1 rpm. The degree of true deformation e upon HPT was determined by the formula [14]:
e ¼ ln 1 þ
2 !0:5 /r h0 þ ln ; h h
ð1Þ
2
A.M. Glezer et al. / Materials Letters 256 (2019) 126631
where r and h are the radius and height of the disk sample, respectively, and u is the rotation angle of the movable anvil. According to Eq. (1), e ranges from 6 to 9. In addition, alloy 2 underwent thermal cycling (110 cycles) by rapid cooling to a temperature of 77 K and subsequent rapid heating to a temperature of 450 K. The XRD analysis of the samples before and after SPD was performed with a Rigaku Ultima IV diffractometer using CoRa radiation. Vickers microindentation (HV) was carried out with an 1102 tester at a load of 0.1 N with computer control. The HV results were averaged from 20 measurements. The amorphous alloys are characterized by the formation of a ‘‘pileup” at the base of the indent because of a quite high tendency to local plastic flow. The ‘‘pileup” can be described by a wave, whose height h and crest position are determined by the plasticity of the deformed volume [4]. For an objective estimation of plasticity, one should correlate the ‘‘pileup” height h at the recovered indent with its depth H in the form [4]:
dh ¼ ðh=HÞ
ð2Þ
Eq. (2) allows for the fact that the degree of plastic deformation upon indentation is distributed between the indent itself and the ‘‘pileup”. The smaller is H (the higher is HV), the higher would be h [15]. At HV const, the dh parameter in Eq. (2) will quite correctly reflect the tendency of amorphous alloy to plastic flow. To evaluate the plasticity of amorphous alloys after HPT, we measured the relative ‘‘pileup” height in accordance with Eq. (2) using optical profilometry with a WYKO NT 1100 instrument. This technique allows one to determine both the indent depth and the pileup height after indentation. The surface was examined in the vertical scanning interferometry (VSI) mode. The resolution of the profilometer, depending on the record method, ranged from 0.1 nm to 0.1 lm. The relative ‘‘pileup” height results were averaged from 10 indents.
planes on the sample surface are shown in Fig. 1a). For each indent, h was averaged over four points. Then h was averaged for 10 indents obtained in the middle of the sample radius. The plasticity should be most correctly determined at constant HV (or indent depth). We adjusted h by reducing it to constant HV in the following form:
Dh ¼ dh ½1 ðDHV=HV0 Þ;
ð3Þ
where DHV = HVn–HV0, HVn is the microhardness after HPT (n = 16), and HV0 is the microhardness in the initial state. Fig. 2 shows the dependences of HV, dh, and Dh on the degree of deformation n by HPT for alloy 1. There is a noticeable increase in HV at n = 1, and, at n 1, HV is constant. The plasticity parameters dh (for different HV) and Dh (reduced to constant HV) are close. A slight difference in them (dh > Dh) is associated with an increase in HV under the effect of HPT. The plasticity increases at n 2, remains constant at 2 < n < 5, and abruptly decreases at n > 5. The plasticity of amorphous alloy 2 is similarly affected by HPT (Fig. 3). The Dh parameter after HPT to n = 5 or after thermal cycling (77 M 450 K) steadily increases by about 50% in all experiments. We see that there are three following regions of change in plasticity with increasing degree of deformation upon HPT: it increases by 35–50%, then remains at constant increased level, and then abruptly decreases at high degrees of HPT. The increase in plasticity after HPT is similar to that observed after thermal cycling.
3. Results and discussion The analysis of the X-ray diffraction patterns showed that the samples of both alloys after all HPT regimes remained completely amorphous. Fig. 1 shows a typical spatial image of the indent (a) and its profile (b) recorded with a profilometer. The ‘‘pileup” at the base of the indent is clearly visible. The h magnitude was determined at four points at the intersection of the ‘‘pileup” with two mutually perpendicular planes (the AAI and BBI projections of these
Fig. 2. Dependences of HV, dh, and Dh on the degree of deformation n by HPT for the Zr60Cu18.5Nb2Ni7.5Al10Ti2 alloy.
Fig. 1. Front view (a) and profile (b) of the indent and ‘‘pileup” at the base of the indent in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 alloy after HPT at room temperature (n = 2); AA0 and BB0 are the projections of the sections for measuring h.
A.M. Glezer et al. / Materials Letters 256 (2019) 126631
3
deformation n by HPT. At n 2, the plasticity increases by 35–50%. At n = 24, the increased plasticity is stable, and at n 5, the plasticity abruptly decreases and becomes lower than that is in the initial state. 3. The staged character of the change in plasticity is due to the cyclical nature of the evolution of short-range order upon HPT.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Fig. 3. Plasticity parameter Dh for the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy in the initial state (1), after thermal cycling (77 M 450 K) (2), and after HPT to n = 5 (3) for different Vickers microintentation experiments.
Different effects of SPD on the plasticity of amorphous alloys at different stages of HPT are due to the different effects of SPD on the state of amorphous structure. SPD at n < 2 leads to the destruction of the topological and compositional short-range order existing in the initial state [16] and, therefore, the viscoelastic flow is facilitated upon indentation. At high degrees of HPT (n > 5), the processes of short and/or long-range crystalline ordering under the effect of a local adiabatic heating in shear bands begin to play a significant role [17]. The results obtained confirm the effect of an increase in the plasticity of amorphous alloys upon deformation under different stressstate schemes [12,13]. At the same time, they predict a sharp decrease in plasticity upon severe HPT (n > 45). The increase in plasticity after repeated thermal cycling is fully consistent with the ‘‘rejuvenation” effect, which is described in detail in [18]. 4. Conclusions 1. The tendency to plastic flow in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 and Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloys as a function of the degree of preliminary plastic deformation by roomtemperature HPT has been studied by Vickers microindentation and precision measurement of the relative ‘‘pileup” height at the indent base. 2. It has been established that there are three stages in the dependence of the tendency to plastic flow on the degree of
Acknowledgments The work was supported by Science of the Russian Federation in the framework of the Program to Increase the Competitiveness of NUST ‘‘MISiS” (R2-2018-055 and K2-2017-089). References [1] D.B. Miracle, D.V. Louzguine-Luzgin, L.V. Louzguina-Luzgina, A. Inoue, Int. Mater. Rev. 55 (2010) 218–256. [2] C. Suryanarayana, A. Inoue, Bulk Metallic Glasses, Taylor and Francis Group, LLC, 2011, p. 17. [3] D.V. Louzguine-Luzgin, Bulk metallic glasses and glassy/crystalline materials, Springer Series in Materials Science, Springer International Publishing, 2016, pp. 397–440. [4] A.M. Glezer, A.I. Potekaev, A.O. Cheretaeva, Thermal and Time Stability of Amorphous Alloys, Taylor & Francis Group, Boka Raton, 2017, p. 170. [5] E.S. Koba, Yu.V. Milman, A.P. Rachek, Acta Mater. 42 (1994) 1383–1388. [6] Y. Yokoyama, K. Yamano, K. Fukaura, et al., Mater. Trans. 42 (2001) 623–632. [7] A.M. Glezer, R.V. Sundeev, Mater. Lett. 139 (2015) 455–457. [8] B.B. Straumal, V. Pontikis, A.R. Kilmametov, et al., Acta Mater. 122 (2017) 60– 71. [9] A.M. Glezer, M.R. Plotnikova, R.V. Sundeev, N.A. Shurygina, Bull. Russ. Acad. Sci. Phys. 77 (2013) 1391–1396. [10] N. Van Steenberge, S. Hobor, S. Surinach, et al., J. Alloys Compd. 500 (1) (2010) 61–67. [11] Y.B. Wang, D.D. Qu, X.H. Wang, et al., Acta Mater. 60 (1) (2012) 253–260. [12] S.-H. Joo, D.-H. Pi, A.D.H. Setyawan, et al., Sci. Rep. 5 (9660) (2015) 1–9. [13] Y. Zhang, W.H. Wang, A.L. Greer, Nat. Mater. 5 (11) (2006) 857–860. [14] A.P. Zhilyaev, T.G. Langdon, Prog. Mater. Sci. 53 (2008) 893–979. [15] B.-G. Yoo, K.-W. Park, U. Ramamutry, J. Jang, J. Mater. Res. 24 1416 (4) (2009) 1405–1411. [16] K.-W. Park, C.-M. Lee, M. Wakeda, et al., Acta Mater. 56 (2008) 5440–5450. [17] R.V. Sundeev, A.V. Shalimova, A.A. Veligzhanin, et al., J. Alloys Compd. 797 (2019) 622–629. [18] S.V. Ketov, Y.H. Sun, S. Nachum, et al., Nature 524 (7564) (2015) 200–203.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Effect of high-pressure torsion on the tendency to plastic flow in bulk amorphous alloys based on Zr A.M. Glezer a,⇑, D.V. Louzguine-Luzgin b,c, I.A. Khriplivets a, R.V. Sundeev d, D.V. Gunderov e, A.I. Bazlov a, Yu.S. Pogozhev a a
National University of Science and Technology «MISIS», 119049, Leninskiy pr. 4, Moscow, Russia WPI Advanced Institute for Materials Research, Tohoku University, Aoba-Ku, Sendai 980-8577, Japan MathAM-OIL, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 980-8577, Japan d ‘‘MIREA - Russian Technological University”, 119454, Vernadskogo pr. 78, Moscow, Russia e Institute of Molecule and Crystal Physics of Ufa Federal Research Centre RAS, 450075, Prospekt Oktyabrya 151, Ufa, Russia b c
a r t i c l e
i n f o
Article history: Received 1 September 2019 Accepted 4 September 2019 Available online 5 September 2019 Keywords: Severe plastic deformation High-pressure torsion Bulk amorphous alloys Pileup Microhardness
a b s t r a c t The effect of the degree of room-temperature plastic deformation by high-pressure torsion on the tendency to plastic flow in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 and Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloys has been studied by Vickers microindentation and precision measurements of the relative height of the ‘‘pileup” at the base of the indent. Three stages of the dependence of plasticity on the number of full revolutions of the moving anvil upon high pressure torsion of the alloys have been established. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction One of the unique properties of amorphous alloys is their ability to plastic flow [1–3]. Deformation generally occurs by strongly localized shear bands 20–30 nm thick [3,4]. It has been established that the preliminary deformation of Fe-, Co-, and Zr-based amorphous alloys can either increase or decrease their strength [5]. In addition, it was found [6] that the preliminary deformation of the Zr55Cu30Al10Ni5 amorphous alloy increases its plasticity. In recent years, methods of severe plastic deformation (SPD) have been intensely developed [7,8]. In the case where SPD is applied to amorphous alloys (for example, by high pressure torsion (HPT)), the plastic flow is accompanied by a noticeable increase in the bulk density of shear bands and the delocalization of plastic deformation [9]. The measurement of the mechanical properties of amorphous alloys after HPT revealed both a noticeable decrease (the Zr44Ti11Cu10Ni10Be25 alloy) [10] or an increase (the Zr50.7Cu28Ni9Al12.3 alloy) in strength and microhardness [11]. In some works, the plasticity of amorphous alloys was quite unexpectedly observed to be
⇑ Corresponding author. E-mail address: [email protected] (A.M. Glezer). https://doi.org/10.1016/j.matlet.2019.126631 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
substantially increased after HPT [12,13]. The increase in plasticity of amorphous alloys after HPT remains a controversial and insufficiently established phenomenon. In this paper, we attempted to evaluate the effect of HPT on the plasticity of bulk amorphous Zr-based alloys by the microindentation method. 2. Experimental The ingots of the Zr60Cu18.5Nb2Ni7.5Al10Ti2 (1) b Zr52.5Cu17.9Ni14.6Al10Ti5 (2) Zr-based alloys (the compositions are given in nominal atomic percents) were prepared by arc melting of the mixtures of the pure (99.9 mass%) metals in an argon atmosphere. Bulk rod samples of 6 mm in diameter were prepared from the ingots by induction melting and the copper-mold casting technique. Disks 0.75 mm thick manufactured from the rods were subjected to HPT to different numbers of full revolutions of the movable anvil (n = 16) at a quasi-hydrostatic pressure of 6 GPa and at a rotation speed of the movable anvil of 1 rpm. The degree of true deformation e upon HPT was determined by the formula [14]:
e ¼ ln 1 þ
2 !0:5 /r h0 þ ln ; h h
ð1Þ
2
A.M. Glezer et al. / Materials Letters 256 (2019) 126631
where r and h are the radius and height of the disk sample, respectively, and u is the rotation angle of the movable anvil. According to Eq. (1), e ranges from 6 to 9. In addition, alloy 2 underwent thermal cycling (110 cycles) by rapid cooling to a temperature of 77 K and subsequent rapid heating to a temperature of 450 K. The XRD analysis of the samples before and after SPD was performed with a Rigaku Ultima IV diffractometer using CoRa radiation. Vickers microindentation (HV) was carried out with an 1102 tester at a load of 0.1 N with computer control. The HV results were averaged from 20 measurements. The amorphous alloys are characterized by the formation of a ‘‘pileup” at the base of the indent because of a quite high tendency to local plastic flow. The ‘‘pileup” can be described by a wave, whose height h and crest position are determined by the plasticity of the deformed volume [4]. For an objective estimation of plasticity, one should correlate the ‘‘pileup” height h at the recovered indent with its depth H in the form [4]:
dh ¼ ðh=HÞ
ð2Þ
Eq. (2) allows for the fact that the degree of plastic deformation upon indentation is distributed between the indent itself and the ‘‘pileup”. The smaller is H (the higher is HV), the higher would be h [15]. At HV const, the dh parameter in Eq. (2) will quite correctly reflect the tendency of amorphous alloy to plastic flow. To evaluate the plasticity of amorphous alloys after HPT, we measured the relative ‘‘pileup” height in accordance with Eq. (2) using optical profilometry with a WYKO NT 1100 instrument. This technique allows one to determine both the indent depth and the pileup height after indentation. The surface was examined in the vertical scanning interferometry (VSI) mode. The resolution of the profilometer, depending on the record method, ranged from 0.1 nm to 0.1 lm. The relative ‘‘pileup” height results were averaged from 10 indents.
planes on the sample surface are shown in Fig. 1a). For each indent, h was averaged over four points. Then h was averaged for 10 indents obtained in the middle of the sample radius. The plasticity should be most correctly determined at constant HV (or indent depth). We adjusted h by reducing it to constant HV in the following form:
Dh ¼ dh ½1 ðDHV=HV0 Þ;
ð3Þ
where DHV = HVn–HV0, HVn is the microhardness after HPT (n = 16), and HV0 is the microhardness in the initial state. Fig. 2 shows the dependences of HV, dh, and Dh on the degree of deformation n by HPT for alloy 1. There is a noticeable increase in HV at n = 1, and, at n 1, HV is constant. The plasticity parameters dh (for different HV) and Dh (reduced to constant HV) are close. A slight difference in them (dh > Dh) is associated with an increase in HV under the effect of HPT. The plasticity increases at n 2, remains constant at 2 < n < 5, and abruptly decreases at n > 5. The plasticity of amorphous alloy 2 is similarly affected by HPT (Fig. 3). The Dh parameter after HPT to n = 5 or after thermal cycling (77 M 450 K) steadily increases by about 50% in all experiments. We see that there are three following regions of change in plasticity with increasing degree of deformation upon HPT: it increases by 35–50%, then remains at constant increased level, and then abruptly decreases at high degrees of HPT. The increase in plasticity after HPT is similar to that observed after thermal cycling.
3. Results and discussion The analysis of the X-ray diffraction patterns showed that the samples of both alloys after all HPT regimes remained completely amorphous. Fig. 1 shows a typical spatial image of the indent (a) and its profile (b) recorded with a profilometer. The ‘‘pileup” at the base of the indent is clearly visible. The h magnitude was determined at four points at the intersection of the ‘‘pileup” with two mutually perpendicular planes (the AAI and BBI projections of these
Fig. 2. Dependences of HV, dh, and Dh on the degree of deformation n by HPT for the Zr60Cu18.5Nb2Ni7.5Al10Ti2 alloy.
Fig. 1. Front view (a) and profile (b) of the indent and ‘‘pileup” at the base of the indent in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 alloy after HPT at room temperature (n = 2); AA0 and BB0 are the projections of the sections for measuring h.
A.M. Glezer et al. / Materials Letters 256 (2019) 126631
3
deformation n by HPT. At n 2, the plasticity increases by 35–50%. At n = 24, the increased plasticity is stable, and at n 5, the plasticity abruptly decreases and becomes lower than that is in the initial state. 3. The staged character of the change in plasticity is due to the cyclical nature of the evolution of short-range order upon HPT.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Fig. 3. Plasticity parameter Dh for the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy in the initial state (1), after thermal cycling (77 M 450 K) (2), and after HPT to n = 5 (3) for different Vickers microintentation experiments.
Different effects of SPD on the plasticity of amorphous alloys at different stages of HPT are due to the different effects of SPD on the state of amorphous structure. SPD at n < 2 leads to the destruction of the topological and compositional short-range order existing in the initial state [16] and, therefore, the viscoelastic flow is facilitated upon indentation. At high degrees of HPT (n > 5), the processes of short and/or long-range crystalline ordering under the effect of a local adiabatic heating in shear bands begin to play a significant role [17]. The results obtained confirm the effect of an increase in the plasticity of amorphous alloys upon deformation under different stressstate schemes [12,13]. At the same time, they predict a sharp decrease in plasticity upon severe HPT (n > 45). The increase in plasticity after repeated thermal cycling is fully consistent with the ‘‘rejuvenation” effect, which is described in detail in [18]. 4. Conclusions 1. The tendency to plastic flow in the Zr60Cu18.5Nb2Ni7.5Al10Ti2 and Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloys as a function of the degree of preliminary plastic deformation by roomtemperature HPT has been studied by Vickers microindentation and precision measurement of the relative ‘‘pileup” height at the indent base. 2. It has been established that there are three stages in the dependence of the tendency to plastic flow on the degree of
Acknowledgments The work was supported by Science of the Russian Federation in the framework of the Program to Increase the Competitiveness of NUST ‘‘MISiS” (R2-2018-055 and K2-2017-089). References [1] D.B. Miracle, D.V. Louzguine-Luzgin, L.V. Louzguina-Luzgina, A. Inoue, Int. Mater. Rev. 55 (2010) 218–256. [2] C. Suryanarayana, A. Inoue, Bulk Metallic Glasses, Taylor and Francis Group, LLC, 2011, p. 17. [3] D.V. Louzguine-Luzgin, Bulk metallic glasses and glassy/crystalline materials, Springer Series in Materials Science, Springer International Publishing, 2016, pp. 397–440. [4] A.M. Glezer, A.I. Potekaev, A.O. Cheretaeva, Thermal and Time Stability of Amorphous Alloys, Taylor & Francis Group, Boka Raton, 2017, p. 170. [5] E.S. Koba, Yu.V. Milman, A.P. Rachek, Acta Mater. 42 (1994) 1383–1388. [6] Y. Yokoyama, K. Yamano, K. Fukaura, et al., Mater. Trans. 42 (2001) 623–632. [7] A.M. Glezer, R.V. Sundeev, Mater. Lett. 139 (2015) 455–457. [8] B.B. Straumal, V. Pontikis, A.R. Kilmametov, et al., Acta Mater. 122 (2017) 60– 71. [9] A.M. Glezer, M.R. Plotnikova, R.V. Sundeev, N.A. Shurygina, Bull. Russ. Acad. Sci. Phys. 77 (2013) 1391–1396. [10] N. Van Steenberge, S. Hobor, S. Surinach, et al., J. Alloys Compd. 500 (1) (2010) 61–67. [11] Y.B. Wang, D.D. Qu, X.H. Wang, et al., Acta Mater. 60 (1) (2012) 253–260. [12] S.-H. Joo, D.-H. Pi, A.D.H. Setyawan, et al., Sci. Rep. 5 (9660) (2015) 1–9. [13] Y. Zhang, W.H. Wang, A.L. Greer, Nat. Mater. 5 (11) (2006) 857–860. [14] A.P. Zhilyaev, T.G. Langdon, Prog. Mater. Sci. 53 (2008) 893–979. [15] B.-G. Yoo, K.-W. Park, U. Ramamutry, J. Jang, J. Mater. Res. 24 1416 (4) (2009) 1405–1411. [16] K.-W. Park, C.-M. Lee, M. Wakeda, et al., Acta Mater. 56 (2008) 5440–5450. [17] R.V. Sundeev, A.V. Shalimova, A.A. Veligzhanin, et al., J. Alloys Compd. 797 (2019) 622–629. [18] S.V. Ketov, Y.H. Sun, S. Nachum, et al., Nature 524 (7564) (2015) 200–203.