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Ferritic alloys strengthened by β′ phase and nanosized oxide
Materials Letters 117 (2014) 286–289
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Ferritic alloys strengthened by β′ phase and nanosized oxide Lin Zhang a,n, Xuanhui Qu a, Rafi-ud din b, Mingli Qin a, Yue Wang a a b
Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, PR China Materials Division, PINSTECH, P.O. Box, Nilore, Islamabad, Pakistan
art ic l e i nf o
a b s t r a c t
Article history: Received 20 November 2013 Accepted 30 November 2013 Available online 7 December 2013
Ferritic alloys, strengthened by precipitating dispersed NiAl intermetallic compound (β′) and nanosized oxides, were fabricated by mechanical alloying route. The particle size evolution, chemistry, and interfacial structure of the nanoprecipitates were investigated. The near spherical β′ phase with volume fraction of 17.9% and an average diameter of 124 nm was obtained. The oxide nanoparticles, with a particle size of 3–8 nm, were uniformly distributed in α-Fe matrix. Moreover, both the β′ phase and nanosized oxides were found to be coherent or semi-coherent with the matrix. The β/β′ Fe-based ODS alloys can be considered as a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys. & 2013 Published by Elsevier B.V.
Keywords: Metals and alloys Nanoparticles Electron microscopy Microstructure
1. Introduction Ferritic alloys, based on 9–12 wt% Cr–steel, exhibit lower thermal expansion, higher thermal conductivity, good oxidation resistance, and lower material costs. These advantages of ferritic alloys have rendered them very attractive for their use in high-temperature applications, such as the fabrication of heat exchangers in advanced powder plant or the structural materials in nuclear reactors [1–2]. However, the lack of high temperature creep strength of these alloys with increasing service temperature necessitates the further improvement of their mechanical properties [3]. The use of second-phase nanoparticles is one of the most important methods to extend the high-temperature strength limit of ferritic alloys [4–5]. On the one hand, body-centered cubic (bcc)-based ordered B2-type NiAl precipitates (β′) are effective intermetallic strengthening species [6]. β′ phase demonstrates obvious strengthening effect by virtue of the creation of antiphase boundaries or coherent strains that effectively impede dislocation motion [7]. The conventional way of synthesizing an alloy doped with oxide particles involves the high-energy ball milling with the addition of Y2O3 [8]. In the present work, less thermodynamically stable Fe2O3 and YH2 were used as raw materials, which can be completely dissolved during ball milling [9], resulting in the formation of Y2O3 nanoparticles thorough the mechanochemistry reaction between YH2 and Fe2O3. The utilization of combination of above two kinds of strengthening phases points out a new direction in the design of novel β/β′ Fe-base ODS alloy. It is expected that the intermediate temperature strength can be enhanced by employing the β′phase, while
nanosized oxides are more effective at elevated temperature. Moreover, β/β′ Fe-base ODS alloy has low density and low cost, which is a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys. β/β′ Fe-base ODS alloys are fabricated via mechanical alloying. The chemical composition, particle size, and interfacial structure of above two kinds of precipitates have been characterized. This information aids in designing the alloy compositions and the microstructure optimization.
2. Experimental Ferritic ODS alloys with the composition of Fe-6.5Al-11.4Ni8.8Cr-3.4Mo-0.4YH2-(0.17~0.35)Fe2O3 (wt. %) were designed. Firstly, the powder mixture was mechanical alloyed in a high energy planetary ball mill at a rotation speed of 300–350 rpm with the ball/powder weight ratio of 10:1 in Ar atmosphere for 5 min–48 h. Secondly, the MA powder was consolidated by spark plasma sintering (SPS) at 970 1C with the pressure of 50 MPa. Finally, the specimens were solution treated at 1200 1C for 1 h and aged at 700 1C for 48 h. The phase constituents of the alloys were identified by a Rigaku D/max-RB12 X-Ray diffract meter with Cu Kα radiation. The oxygen content of the powder was analyzed by using a LECO TN-114 nitrogen-oxygen analyzer. The microstructure of the alloy was examined by JSM-7001F field emission scanning electron microscopy. JEM-2010 transmission electron microscopy (TEM) was employed to observe the morphology of the nanoprecipitates.
3. Results and discussion n
Corresponding author. E-mail address: [email protected] (L. Zhang).
0167-577X/$ - see front matter & 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.matlet.2013.11.127
Fig. 1(a) depicts the XRD patterns of the powder mixture milled for various periods of time. In case of the powder milled for 5 min,
L. Zhang et al. / Materials Letters 117 (2014) 286–289
the peaks of YH2, Fe2O3 and Al are detected. The intensity of YH2, Fe2O3 and Al diffraction peaks decrease with increasing milling time. Only the width broadening of the α-Fe diffraction peak has been observed for the powder milled for 20 h, implying the complete dissolution or decomposition of Fe2O3 and YH2 in α-Fe matrix. One important factor for the refinement of the oxides is the reduction of excess oxygen contents effectively. The excess oxygen contents are determined by subtracting the amount of oxygen contained in Y2O3 from the total oxygen contents. Fig. 1 (b) shows the average particle size and extra oxygen contents of the MA powder as a function of milling time. Particle size of the MA powder increases with increasing milling time. After milling for 20 h, the dramatic refinement of particle size is observed due to the disintegration of powder particles. With the disintegration of powder particles, the extra oxygen contents of the 0.35% Fe2O3added powder increases sharply due to the absorption of impurity oxygen at solid/gas interface [10]. In the case of powder with the addition of 0.17% Fe2O3, the extra oxygen contents increases slightly and the final extra oxygen contents are much lower than that of the 0.35% Fe2O3-added powder. Fig. 2 displays the microstructure of the heat treated β/β′ Febased ODS alloys. Fig. 2(a) clearly indicates the presence of small amount of irregular white precipitates (marked by W) in the microstructure. Additionally, a large quantity of near spherical dark phase has precipitated in a body-centered cubic (BCC) α-Fe matrix. By combining the XRD result, the dark precipitates are NiAl-type phase with the B2 structure (designated as β′). The volume fraction of β′ phase is measured to be 17.9%, and the number density of β′ phase is 7.0 1019 m 3. β′ phase has an average particle size of 124 nm. The high magnification microstructure of the alloy demonstrates the formation of β/β′ twophase microstructure (inset in Fig. 2(a)). It is also evident in Fig. 2 (b) that the β/β′ Fe-based ODS alloys are consisted of α-ferrite, NiAl (β′ phase), Al95Fe4Cr, and Mo. Table 1 lists the average chemical compositions of various phases observed in Fig. 2(a). The contents of Al (23.16 at%) and
287
Ni (20.43 at%) in the black precipitates, marked by D, are roughly the same and corresponds to the β′ precipitates. The black phase shows high contents of Al (38.22 at%). The contents of Mo in the irregular white phase (W) is as high as 11.18 at%. In accordance with the XRD results, the white phase is identified to be the undissolved Mo. The most of Mo remains in the matrix with only a small amount is partitioned into the NiAl precipitates. The solid solution of Mo into α-Fe matrix reduces the lattice misfit between β′ precipitates and α-Fe matrix, resulting in the stabilization of the spherical morphology of β′ phase. Fig. 3 shows the dark field TEM images of β/β′ Fe-based ODS alloy and the corresponding selected area diffraction pattern. Fig. 3(a) clearly reveals that near spherical β′ phase has precipitated from the matrix. The particle size of β′ phase is in the range of 52–161 nm. Fig. 3(b) shows the corresponding selected area electron diffraction pattern. β/β′ Fe-based ODS alloys are microstructurally analogous to classical Ni-based γ/γ′ superalloys containing coherent ordered intermetallic precipitates (Ni3Al) in a disordered solid-solution matrix (γ-Ni) [11]. The characteristics of phase boundary between the α-Fe and β′ phase have been studied by HRTEM, as shown in Fig. 3(c). The central part corresponds to the nanoparticle/matrix interface region showing dark contrast, as indicated by the dotted white curve. Fig. 3(d) indicates the high magnification image of the interfacial domain. The atomic planes across boundary of α-Fe and β′ phase have displayed the continuity, implying the presence of a certain degree of coherency.
Table 1 Chemical composition of various phases observed in Fig. 2(a) (at%). Domain
Ni
Al
Cr
Mo
Fe
α-ferrite matrix β′ phase (marked by D) Black phase (marked by B) White phase (marked by W)
7.86 20.43 3.67 5.65
6.56 23.16 38.22 15.6
6.53 8.33 12.26 10.95
2.42 – 2.28 11.18
74.84 49.88 43.57 56.62
Fig. 1. XRD patterns of the powder mixture milled for various periods of time, and the effect of milling time on particle size and excess oxygen contents of the powder.
Fig. 2. SEM images of the heat treated alloy (a) and the corresponding XRD pattern (b).
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L. Zhang et al. / Materials Letters 117 (2014) 286–289
Fig. 3. (a) The ark field TEM images of β/β′ Fe-based ODS alloys and corresponding selected area diffraction pattern (b), HRTEM image (c), and the FFT image (d).
Fig. 4. The bright field TEM image of β/β′ Fe-based ODS alloys (a) and the HRTEM image of nanosized oxide (b), as well as the EDS result (c).
L. Zhang et al. / Materials Letters 117 (2014) 286–289
The measured lattice parameters for the ferritic matrix (αα) and the β′ precipitate (αβ′) are 2.0381 Å and 2.0362 Å, respectively, for, α α which corresponds to a lattice misfit (δ ¼ j α αα β′ j) of 0.09%. The small lattice misfit brings about the formation of coherent interfacial structure, contributing to the improved stability of highdensity β′ precipitate during prolonged aging. The high lattice coherency of β′ precipitation can accommodate the extra energy needed to create the antiphase boundaries, and making it easier for dislocation to cut through the nanoscale precipitates. Fig. 3(d) shows the inverse fast Fourier transform (FFT) image, which is reconstructed by using the diffraction spots with scattering vectors parallel to the interface, as shown in the inset of Fig. 3(d). Fig. 4(a) displays the TEM image of β/β′ Fe-based ODS alloys. A high density of oxide nanoparticles distribute uniformly in the matrix. It is clearly demonstrated that the size of these oxide particles is in the range of 3–8 nm with irregular shape. The number density of these nanosized oxide nanoparticles is found to be 1.7 1024 m 3. The detailed interfacial structure of the oxide nanoparticle is displayed in Fig. 4(b). The plane distance is measured to be 2.61 Å and 1.89 Å, respectively, which corresponds to (200) and (220) planes of Y2O3 oxides. The lattice continuity between the oxides and surrounding matrix is also clearly observed, suggesting that oxide nanoparticles remain coherently within a-Fe. The reduced interfacial energy favors the homogeneous nucleation of the oxides and accounts for the enhanced stability of these nanoparticles. Fig. 4(c) shows the EDS analysis of the oxide particle. It is obvious that the oxide is composed of Y and O. Hence, in accordance with the XRD and EDS results, these oxide particles are confirmed to be Y2O3 oxides. 4. Conclusions The β/β′ Fe-based ODS alloys were successfully fabricated by mechanical alloying. The β/β′ Fe-based ODS alloys were strengthened
289
by a high volume fraction (17.9%) of β′ intermetallic compound with a mean precipitate size of 124 nm and a high density of nanosized oxide particles with a precipitate size of below 8 nm. Both NiAl-type intermetallic phase and nanosized oxides were found to be coherent or partially coherent with the matrix. It is expected that β/β′ Fe-based ODS alloy has high strength without significantly loss in the ductility. In short, the β/β′ Fe-based ODS alloys can be considered as a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys.
Acknowledgments The research was financially supported by National Nature Science Foundation of China (51104007) and Beijing Natural Science Foundation (2132046).
References [1] Edahiro T, Kouzai K, Yasuda HY. Acta Mater 2013;61:1716–22. [2] Teng ZK, Liu CT, Miller MK, Ghosh G, Kenik EA, Huang S, et al. Mater Sci Eng A 2012;541:22–8. [3] Stallybrass C, Schneider A, Sauthoff G. Intermetallics 2005;13:1263–9. [4] Wen YR, Hirata A, Zhang ZW, Fujita T, Liu CT, Jiang JH, et al. Acta Mater 2013;61:2133–9. [5] Teng ZK, Ghosh G, Miller MK, Huang S, Clausen B, Brown DW, et al. Acta Mater 2012;60:5362–8. [6] Edahiro T, Kouzai K, Yasuda HY. Acta Mater 2012;61:1716–22. [7] Erlach SD, Leitner H, Bischof M, Clemens H, Danoix F, Lemarchand D, et al. Mater Sci Eng A 2006;429:96–102. [8] Alinger MJ, Odette GR, Hoelzer DT. Acta Mater 2009;57:392–8. [9] Brocq M, Radiguet B, Poissonnet S, Cuvilly F, Pareige P. J Nucl Mater 2011;409:80–6. [10] Wen YR, Liu Y, Liu F, Fujita T, Liu DH, Chen MW, et al. J Nucl Mater 2010;405:199–202. [11] Nganbe M, Heilmaier M. Mater Sci Eng A 2004;387–389:609–15.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Ferritic alloys strengthened by β′ phase and nanosized oxide Lin Zhang a,n, Xuanhui Qu a, Rafi-ud din b, Mingli Qin a, Yue Wang a a b
Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, PR China Materials Division, PINSTECH, P.O. Box, Nilore, Islamabad, Pakistan
art ic l e i nf o
a b s t r a c t
Article history: Received 20 November 2013 Accepted 30 November 2013 Available online 7 December 2013
Ferritic alloys, strengthened by precipitating dispersed NiAl intermetallic compound (β′) and nanosized oxides, were fabricated by mechanical alloying route. The particle size evolution, chemistry, and interfacial structure of the nanoprecipitates were investigated. The near spherical β′ phase with volume fraction of 17.9% and an average diameter of 124 nm was obtained. The oxide nanoparticles, with a particle size of 3–8 nm, were uniformly distributed in α-Fe matrix. Moreover, both the β′ phase and nanosized oxides were found to be coherent or semi-coherent with the matrix. The β/β′ Fe-based ODS alloys can be considered as a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys. & 2013 Published by Elsevier B.V.
Keywords: Metals and alloys Nanoparticles Electron microscopy Microstructure
1. Introduction Ferritic alloys, based on 9–12 wt% Cr–steel, exhibit lower thermal expansion, higher thermal conductivity, good oxidation resistance, and lower material costs. These advantages of ferritic alloys have rendered them very attractive for their use in high-temperature applications, such as the fabrication of heat exchangers in advanced powder plant or the structural materials in nuclear reactors [1–2]. However, the lack of high temperature creep strength of these alloys with increasing service temperature necessitates the further improvement of their mechanical properties [3]. The use of second-phase nanoparticles is one of the most important methods to extend the high-temperature strength limit of ferritic alloys [4–5]. On the one hand, body-centered cubic (bcc)-based ordered B2-type NiAl precipitates (β′) are effective intermetallic strengthening species [6]. β′ phase demonstrates obvious strengthening effect by virtue of the creation of antiphase boundaries or coherent strains that effectively impede dislocation motion [7]. The conventional way of synthesizing an alloy doped with oxide particles involves the high-energy ball milling with the addition of Y2O3 [8]. In the present work, less thermodynamically stable Fe2O3 and YH2 were used as raw materials, which can be completely dissolved during ball milling [9], resulting in the formation of Y2O3 nanoparticles thorough the mechanochemistry reaction between YH2 and Fe2O3. The utilization of combination of above two kinds of strengthening phases points out a new direction in the design of novel β/β′ Fe-base ODS alloy. It is expected that the intermediate temperature strength can be enhanced by employing the β′phase, while
nanosized oxides are more effective at elevated temperature. Moreover, β/β′ Fe-base ODS alloy has low density and low cost, which is a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys. β/β′ Fe-base ODS alloys are fabricated via mechanical alloying. The chemical composition, particle size, and interfacial structure of above two kinds of precipitates have been characterized. This information aids in designing the alloy compositions and the microstructure optimization.
2. Experimental Ferritic ODS alloys with the composition of Fe-6.5Al-11.4Ni8.8Cr-3.4Mo-0.4YH2-(0.17~0.35)Fe2O3 (wt. %) were designed. Firstly, the powder mixture was mechanical alloyed in a high energy planetary ball mill at a rotation speed of 300–350 rpm with the ball/powder weight ratio of 10:1 in Ar atmosphere for 5 min–48 h. Secondly, the MA powder was consolidated by spark plasma sintering (SPS) at 970 1C with the pressure of 50 MPa. Finally, the specimens were solution treated at 1200 1C for 1 h and aged at 700 1C for 48 h. The phase constituents of the alloys were identified by a Rigaku D/max-RB12 X-Ray diffract meter with Cu Kα radiation. The oxygen content of the powder was analyzed by using a LECO TN-114 nitrogen-oxygen analyzer. The microstructure of the alloy was examined by JSM-7001F field emission scanning electron microscopy. JEM-2010 transmission electron microscopy (TEM) was employed to observe the morphology of the nanoprecipitates.
3. Results and discussion n
Corresponding author. E-mail address: [email protected] (L. Zhang).
0167-577X/$ - see front matter & 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.matlet.2013.11.127
Fig. 1(a) depicts the XRD patterns of the powder mixture milled for various periods of time. In case of the powder milled for 5 min,
L. Zhang et al. / Materials Letters 117 (2014) 286–289
the peaks of YH2, Fe2O3 and Al are detected. The intensity of YH2, Fe2O3 and Al diffraction peaks decrease with increasing milling time. Only the width broadening of the α-Fe diffraction peak has been observed for the powder milled for 20 h, implying the complete dissolution or decomposition of Fe2O3 and YH2 in α-Fe matrix. One important factor for the refinement of the oxides is the reduction of excess oxygen contents effectively. The excess oxygen contents are determined by subtracting the amount of oxygen contained in Y2O3 from the total oxygen contents. Fig. 1 (b) shows the average particle size and extra oxygen contents of the MA powder as a function of milling time. Particle size of the MA powder increases with increasing milling time. After milling for 20 h, the dramatic refinement of particle size is observed due to the disintegration of powder particles. With the disintegration of powder particles, the extra oxygen contents of the 0.35% Fe2O3added powder increases sharply due to the absorption of impurity oxygen at solid/gas interface [10]. In the case of powder with the addition of 0.17% Fe2O3, the extra oxygen contents increases slightly and the final extra oxygen contents are much lower than that of the 0.35% Fe2O3-added powder. Fig. 2 displays the microstructure of the heat treated β/β′ Febased ODS alloys. Fig. 2(a) clearly indicates the presence of small amount of irregular white precipitates (marked by W) in the microstructure. Additionally, a large quantity of near spherical dark phase has precipitated in a body-centered cubic (BCC) α-Fe matrix. By combining the XRD result, the dark precipitates are NiAl-type phase with the B2 structure (designated as β′). The volume fraction of β′ phase is measured to be 17.9%, and the number density of β′ phase is 7.0 1019 m 3. β′ phase has an average particle size of 124 nm. The high magnification microstructure of the alloy demonstrates the formation of β/β′ twophase microstructure (inset in Fig. 2(a)). It is also evident in Fig. 2 (b) that the β/β′ Fe-based ODS alloys are consisted of α-ferrite, NiAl (β′ phase), Al95Fe4Cr, and Mo. Table 1 lists the average chemical compositions of various phases observed in Fig. 2(a). The contents of Al (23.16 at%) and
287
Ni (20.43 at%) in the black precipitates, marked by D, are roughly the same and corresponds to the β′ precipitates. The black phase shows high contents of Al (38.22 at%). The contents of Mo in the irregular white phase (W) is as high as 11.18 at%. In accordance with the XRD results, the white phase is identified to be the undissolved Mo. The most of Mo remains in the matrix with only a small amount is partitioned into the NiAl precipitates. The solid solution of Mo into α-Fe matrix reduces the lattice misfit between β′ precipitates and α-Fe matrix, resulting in the stabilization of the spherical morphology of β′ phase. Fig. 3 shows the dark field TEM images of β/β′ Fe-based ODS alloy and the corresponding selected area diffraction pattern. Fig. 3(a) clearly reveals that near spherical β′ phase has precipitated from the matrix. The particle size of β′ phase is in the range of 52–161 nm. Fig. 3(b) shows the corresponding selected area electron diffraction pattern. β/β′ Fe-based ODS alloys are microstructurally analogous to classical Ni-based γ/γ′ superalloys containing coherent ordered intermetallic precipitates (Ni3Al) in a disordered solid-solution matrix (γ-Ni) [11]. The characteristics of phase boundary between the α-Fe and β′ phase have been studied by HRTEM, as shown in Fig. 3(c). The central part corresponds to the nanoparticle/matrix interface region showing dark contrast, as indicated by the dotted white curve. Fig. 3(d) indicates the high magnification image of the interfacial domain. The atomic planes across boundary of α-Fe and β′ phase have displayed the continuity, implying the presence of a certain degree of coherency.
Table 1 Chemical composition of various phases observed in Fig. 2(a) (at%). Domain
Ni
Al
Cr
Mo
Fe
α-ferrite matrix β′ phase (marked by D) Black phase (marked by B) White phase (marked by W)
7.86 20.43 3.67 5.65
6.56 23.16 38.22 15.6
6.53 8.33 12.26 10.95
2.42 – 2.28 11.18
74.84 49.88 43.57 56.62
Fig. 1. XRD patterns of the powder mixture milled for various periods of time, and the effect of milling time on particle size and excess oxygen contents of the powder.
Fig. 2. SEM images of the heat treated alloy (a) and the corresponding XRD pattern (b).
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L. Zhang et al. / Materials Letters 117 (2014) 286–289
Fig. 3. (a) The ark field TEM images of β/β′ Fe-based ODS alloys and corresponding selected area diffraction pattern (b), HRTEM image (c), and the FFT image (d).
Fig. 4. The bright field TEM image of β/β′ Fe-based ODS alloys (a) and the HRTEM image of nanosized oxide (b), as well as the EDS result (c).
L. Zhang et al. / Materials Letters 117 (2014) 286–289
The measured lattice parameters for the ferritic matrix (αα) and the β′ precipitate (αβ′) are 2.0381 Å and 2.0362 Å, respectively, for, α α which corresponds to a lattice misfit (δ ¼ j α αα β′ j) of 0.09%. The small lattice misfit brings about the formation of coherent interfacial structure, contributing to the improved stability of highdensity β′ precipitate during prolonged aging. The high lattice coherency of β′ precipitation can accommodate the extra energy needed to create the antiphase boundaries, and making it easier for dislocation to cut through the nanoscale precipitates. Fig. 3(d) shows the inverse fast Fourier transform (FFT) image, which is reconstructed by using the diffraction spots with scattering vectors parallel to the interface, as shown in the inset of Fig. 3(d). Fig. 4(a) displays the TEM image of β/β′ Fe-based ODS alloys. A high density of oxide nanoparticles distribute uniformly in the matrix. It is clearly demonstrated that the size of these oxide particles is in the range of 3–8 nm with irregular shape. The number density of these nanosized oxide nanoparticles is found to be 1.7 1024 m 3. The detailed interfacial structure of the oxide nanoparticle is displayed in Fig. 4(b). The plane distance is measured to be 2.61 Å and 1.89 Å, respectively, which corresponds to (200) and (220) planes of Y2O3 oxides. The lattice continuity between the oxides and surrounding matrix is also clearly observed, suggesting that oxide nanoparticles remain coherently within a-Fe. The reduced interfacial energy favors the homogeneous nucleation of the oxides and accounts for the enhanced stability of these nanoparticles. Fig. 4(c) shows the EDS analysis of the oxide particle. It is obvious that the oxide is composed of Y and O. Hence, in accordance with the XRD and EDS results, these oxide particles are confirmed to be Y2O3 oxides. 4. Conclusions The β/β′ Fe-based ODS alloys were successfully fabricated by mechanical alloying. The β/β′ Fe-based ODS alloys were strengthened
289
by a high volume fraction (17.9%) of β′ intermetallic compound with a mean precipitate size of 124 nm and a high density of nanosized oxide particles with a precipitate size of below 8 nm. Both NiAl-type intermetallic phase and nanosized oxides were found to be coherent or partially coherent with the matrix. It is expected that β/β′ Fe-based ODS alloy has high strength without significantly loss in the ductility. In short, the β/β′ Fe-based ODS alloys can be considered as a potential candidate for the replacement of γ/γ′ Ni-base ODS alloys.
Acknowledgments The research was financially supported by National Nature Science Foundation of China (51104007) and Beijing Natural Science Foundation (2132046).
References [1] Edahiro T, Kouzai K, Yasuda HY. Acta Mater 2013;61:1716–22. [2] Teng ZK, Liu CT, Miller MK, Ghosh G, Kenik EA, Huang S, et al. Mater Sci Eng A 2012;541:22–8. [3] Stallybrass C, Schneider A, Sauthoff G. Intermetallics 2005;13:1263–9. [4] Wen YR, Hirata A, Zhang ZW, Fujita T, Liu CT, Jiang JH, et al. Acta Mater 2013;61:2133–9. [5] Teng ZK, Ghosh G, Miller MK, Huang S, Clausen B, Brown DW, et al. Acta Mater 2012;60:5362–8. [6] Edahiro T, Kouzai K, Yasuda HY. Acta Mater 2012;61:1716–22. [7] Erlach SD, Leitner H, Bischof M, Clemens H, Danoix F, Lemarchand D, et al. Mater Sci Eng A 2006;429:96–102. [8] Alinger MJ, Odette GR, Hoelzer DT. Acta Mater 2009;57:392–8. [9] Brocq M, Radiguet B, Poissonnet S, Cuvilly F, Pareige P. J Nucl Mater 2011;409:80–6. [10] Wen YR, Liu Y, Liu F, Fujita T, Liu DH, Chen MW, et al. J Nucl Mater 2010;405:199–202. [11] Nganbe M, Heilmaier M. Mater Sci Eng A 2004;387–389:609–15.