Low-temperature superplasticity of Si-added Mn steels

국문 초록 (Abstract)

초소성은 다결정 재료가 파단 전에 300% 이상의 높은 연신율을 나타내는 능력으로, 주로 결정립계 미끄러짐을 통해 발생한다. 초소성 재료는 뛰어난 연성을 가지고 있으므로, 용접이나 접합 없이 복잡한 형태의 기계 부품을 제작하는 데 매우 적합하다. 이러한 재료 중에서도 철계 초소성 재료는 간단한 공정으로 재료를 제작할 수 있으며, 가격이 저렴하다는 장점이 있다. 그러나, 현재까지 연구된 철계 초소성 재료들은 높은 변형 온도와 낮은 변형률 속도가 반드시 요구되므로 실제 공정에 적용하기에는 한계가 있었다. 따라서 본 연구에서는 이러한 문제점을 해결하기 위해, Si 을 첨가한 중망간 및 고망간 초소성강들을 새롭게 개발하였다.
먼저, Thermo-Calc 소프트웨어를 활용한 열역학 계산을 바탕으로, 새로운 Si 첨가 중망간강 (Fe-10.6Mn-3.5Si, wt%)을 설계하였다. 합금 원소로써 Si 을 선택한 이유는 특정 함량의 Si 을 첨가하였을 때 0.5Tm 이 크게 낮아지면서도, T50 이 급격하게 상승하지 않았기 때문이다. 이 강은 763 K 및 1 × 10-3 s-1 조건에서 303%의 초소성 연신율을 나타냈으며, 이는 기존에 보고된 철계 소재의 초소성 최저 온도보다 110 K 낮은 온도이다. 또한, 이 강은 초소성 성형 모사 후에도 1336 MPa 의 높은 상온 인장 강도를 나타냈다. 이 강의 우수한 저온 초소성은 재결정된 α 결정립과 동적으로 역변태된 γ 결정립 간의 상간 경계 미끄러짐에 기인한 것으로 분석되었다. 이후, 저온 초소성을 향상시키기 위해, 50% 및 80% 냉간 압연된 Fe-10Mn-(0.2, 2.4, 3.5, 5.5)Si (wt%) 시편을 활용하여 Si 함량과 냉간 변형이 저온 초소성 연신율에 미치는 영향을 체계적으로 조사하였다. 그 중 80% 냉간압연된 10Mn-3.5Si 시편은 763 K 및 1 × 10-4 s-1 조건에서 948%의 매우 높은 연신율을 나타냈다. 증가된 냉간 압연률과 Si 함량은 시료 내 저장 에너지를 증가시켜 α 상의 재결정 및 동적 α'-to-γ 역변태의 구동력을 높여 초소성 연신율을 향상시켰다. 또한, 3.5 wt%까지 첨가된 Si 은 α 와 γ 상 간의 경도 차이를 증가시켰고, 이는 상간 경계 미끄러짐을 촉진하는 요소로 작동하여, 결과적으로 초소성 연신율을 더욱 증가시켰다. 그러나, δ 페라이트-(Fe,Mn)3Si 금속간 화합물을 포함하는 50% 냉간 압연된 10Mn-5.5Si 시편은 약 100%의 연신율까지만 동적 α'-to-γ 역변태가 빠르게 진행되어, 추가적인 연신율 향상을 얻지 못했고, 결과적으로 50% 냉간 압연된 10Mn-3.5Si 시편과 유사한 연신율을 나타냈다.
저온 및 고속 변형에서 초소성을 얻기 위해서는 결정립계 미끄러짐의 활성화가 필수적이며, 이는 초미세립 구조에 의해 촉진될 수 있다. 또한, 이 초미세립 구조는 가열 및 고온 변형 중 미세 석출물이 결정립 성장을 억제함으로써 유지될 수 있다. 따라서 고온에서 석출물이 존재할 것으로 예상되는 새로운 Si 및 Ni 첨가 고망간 초소성강 (Fe-14.6Mn-5.5Si-5.3Ni, wt%)을 개발하였다. 이 강은 1 × 10-1 s-1 및 1023 K 조건에서 302%의 초소성 연신율을 나타냈으며, 이는 기존에 보고된 최저 온도보다 100 K 낮은 온도이다. 또한 이 강은 초소성 성형 모사 후 상온에서 높은 인장 강도(1295 MPa)와 연신율(38%)을 함께 나타냈다. 이 강의 저온 및 고속 초소성은 Fe5Ni3Si2 석출물과 δ-(Fe,Mn)3Si 입자가 γ 기지의 결정립 성장을 효과적으로 억제하였고, γ/γ 결정립계에서 미끄러짐이 활발히 발생했기
때문으로 분석되었다. 또한 고온 변형 중 γ 기지와 δ-(Fe,Mn)3Si 입자 사이에서 상간 경계 미끄러짐이 발생하여 초소성을 향상시키는 데 기여한 것으로 판단된다.

다국어 초록 (Multilingual Abstract)

Superplasticity is characterized by the ability of a polycrystalline material to show exceptionally high tensile elongation above 300% before fracturing, primarily achieved
through grain boundary sliding. Due to the significant ductility of superplastic materials, they are well-suited for fabricating complex-shaped mechanical components without welding and joining. Among these materials, superplastic steels offer the advantage of low material and production costs. However, their practical application is challenging due to the requirement of both high deformation temperature and low strain rate. In order to resolve these limitations, superplastic Mn steels were newly developed.
First, based on calculations using Thermo-Calc software, a new Si-added medium Mn steel (Fe-10.6Mn-3.5Si, wt%) was designed. Si was chosen because adding a certain amount significantly reduced a half of melting point (0.5Tm) without causing a dramatic increase in the temperature at which the volume fraction of α ferrite and γ austenite phases are equal. This steel exhibited superplastic elongation of 303% at the lowest deformation temperature (763 K with a strain rate of 1 × 10-3 s-1) and remarkable room-temperature tensile strength (1336 MPa). Low-temperature superplasticity was attributed to interphase boundary sliding occurring between recrystallized α grains and dynamically reverted γ grains. To enhance low-temperature superplasticity, the effects of Si content and cold deformation were systematically investigated using 50% and 80% cold-rolled Fe-10Mn-(0.2, 2.4, 3.5, and 5.5)Si (wt%) specimens. Among them, the 80% cold-rolled 10Mn-3.5Si specimen exhibited significant elongation of 948% at 763 K with a strain rate of 1 × 10-4 s-1. The increased cold reduction and Si content enhanced superplasticity by raising stored energy, a driving force of recrystallization of the α phase and dynamic α'-to-γ reverse transformation. The added Si enhanced interphase boundary sliding by increasing difference in hardness between α and γ phases. However, the 50% cold-rolled 10Mn-5.5Si specimen, containing δ ferrite-(Fe,Mn)3Si compound constituents, exhibited similar elongation to the 50% cold-rolled 10Mn-3.5Si specimen due to the dynamic α'-to-γ reverse transformation occurring rapidly only up to a tensile strain of ~100%.
To achieve superplasticity at both low temperatures and high strain rates, active grain boundary sliding, which is enhanced by an ultrafine-grained microstructure (< 10 μm), becomes crucial. This ultrafine-grained microstructure can be obtained during heating and high-temperature deformation due to suppression of grain coarsening by fine precipitates. Therefore, a new superplastic high Mn steel (Fe-14.6Mn-5.5Si-5.3Ni, wt%), expected to have precipitates at high temperatures, was developed. When this steel was tensile-deformed with a relatively high strain rate of 1 × 10-1 s-1, superplastic elongation of 302% was obtained at 1023 K, which is lower by 100 K than the lowest temperature at the same strain rate. The steel also exhibited high room-temperature tensile strength (1295 MPa) and total elongation (38%) after a superplastic forming simulation. Low-temperature and high strain rate superplasticity was due to sliding occurring at the γ/γ grain boundaries, whose coarsening was suppressed by Fe5Ni3Si2 precipitates and δ-(Fe,Mn)3Si constituent particles. Interphase boundary sliding also occurred between the γ matrix and δ-(Fe,Mn)3Si constituents during high-temperature deformation, which contributed to enhancing superplasticity.

목차 (Table of Contents)

• List of figures --------------------------------------------------------------------------------------------------------------------- iv
• List of tables ----------------------------------------------------------------------------------------------------------------------- xii
• Abstract in English ------------------------------------------------------------------------------------------------------------ xiii
• Nomenclature --------------------------------------------------------------------------------------------------------------------- xv
• 1. Introduction ------------------------------------------------------------------------------------------------------------------- 1
• 1.1. Historical development of superplasticity --------------------------------------------------------- 1
• 1.2. Low-temperature and high-strain rate superplasticity ------------------------------------- 2
• 1.3. Superplastic medium Mn steel ---------------------------------------------------------------------------- 5
• 1.4. Research objective ------------------------------------------------------------------------------------------------ 6
• Reference ----------------------------------------------------------------------------------------------------------------------- 8
• 2. Theoretical background ----------------------------------------------------------------------------------------------- 13
• 2.1. Superplasticity ------------------------------------------------------------------------------------------------------- 13
• 2.2. Requirements for superplasticity ------------------------------------------------------------------------ 16
• 2.3. Grain boundary sliding ----------------------------------------------------------------------------------------- 19
• 2.3.1. Pure grain boundary sliding ------------------------------------------------------------------------- 19
• 2.3.2. Grain boundary sliding accommodated by dislocation --------------------------- 22
• 2.3.3. Grain boundary sliding accommodated by diffusion ------------------------------- 27
• 2.3.4. Other processes with grain boundary sliding -------------------------------------------- 29
• 2.4. Interphase boundary sliding -------------------------------------------------------------------------------- 30
• 2.5. Evaluation parameters for occurrence of grain boundary sliding ------------------ 33
• 2.6. Measurement of strain rate sensitivity ---------------------------------------------------------------39
• 2.6.1. Monotonic tensile test at various strain rates -------------------------------------------- 40
• 2.6.2. Strain rate jump test -------------------------------------------------------------------------------------- 40
• 2.6.3. Stress relaxation test ------------------------------------------------------------------------------------- 42
• Reference ------------------------------------------------------------------------------------------------------------------- 45
• 3. Experimental ----------------------------------------------------------------------------------------------------------------- 50
• 3.1. Alloy design ----------------------------------------------------------------------------------------------------------- 50
• 3.2. Sample preparation ----------------------------------------------------------------------------------------------- 52
• 3.3. Tensile testing -------------------------------------------------------------------------------------------------------- 56
• 3.3.1. High-temperature tensile testing ----------------------------------------------------------------- 56
• 3.3.2. Room-temperature tensile testing --------------------------------------------------------------- 57
• 3.3.3. Monotonic tensile testing ----------------------------------------------------------------------------- 57
• 3.3.4. Strain rate jump test -------------------------------------------------------------------------------------- 58
• 3.4. Dilatometric testing ---------------------------------------------------------------------------------------------- 58
• 3.5. Microstructural observation -------------------------------------------------------------------------------- 59
• 3.5.1. Optical microscope --------------------------------------------------------------------------------------- 59
• 3.5.2. Scanning electron microscope --------------------------------------------------------------------- 59
• 3.5.3. Electron backscattered diffractometer -------------------------------------------------------- 60
• 3.5.4. Transmission electron microscope -------------------------------------------------------------- 60
• 3.5.5. X-ray diffractometer ------------------------------------------------------------------------------------- 61
• 3.5.6. Feritscope ------------------------------------------------------------------------------------------------------- 62
• Reference ------------------------------------------------------------------------------------------------------------------- 63
• 4. Superplasticity of Si-added medium Mn steel --------------------------------------------------------- 65
• 4.1. Introduction ------------------------------------------------------------------------------------------------------------ 65
• 4.2. Initial microstructure -------------------------------------------------------------------------------------------- 66
• 4.3. Tensile property ----------------------------------------------------------------------------------------------------- 70
• 4.4. Deformation mechanism -------------------------------------------------------------------------------------- 73
• 4.5. Summary ---------------------------------------------------------------------------------------------------------------- 86
• Reference ----------------------------------------------------------------------------------------------------------------------- 87
• 5. Si effect on low-temperature superplasticity ------------------------------------------------------------ 93
• 5.1. Introduction ------------------------------------------------------------------------------------------------------------ 93
• 5.2. Initial microstructure -------------------------------------------------------------------------------------------- 94
• 5.3. High-temperature tensile property ---------------------------------------------------------------------- 98
• 5.4. Microstructure after failure ---------------------------------------------------------------------------------- 100
• 5.5. Deformation mechanism -------------------------------------------------------------------------------------- 115
• 5.6. Si effect on low-temperature superplasticity ---------------------------------------------------- 120
• 5.7. Summary ---------------------------------------------------------------------------------------------------------------- 128
• Reference ----------------------------------------------------------------------------------------------------------------------- 130
• 6. Superplasticity of Si- and Ni-added high Mn steel ------------------------------------------------- 133
• 6.1. Introduction ------------------------------------------------------------------------------------------------------------ 133
• 6.2. Initial microstructure -------------------------------------------------------------------------------------------- 134
• 6.3. Tensile property ----------------------------------------------------------------------------------------------------- 136
• 6.4. Precipitate --------------------------------------------------------------------------------------------------------------- 140
• 6.5. Deformation mechanism -------------------------------------------------------------------------------------- 144
• 6.6. Comparison with Si-added medium Mn steels ------------------------------------------------- 153
• 6.6. Summary ---------------------------------------------------------------------------------------------------------------- 159
• Reference ----------------------------------------------------------------------------------------------------------------------- 160
• 7. Conclusions ------------------------------------------------------------------------------------------------------------------- 165
• Abstract in Korean ------------------------------------------------------------------------------------------------------------ 168

참고문헌 (Reference)

1. 32, J. Weertman, 28(3) 362-364, , 1957

2. Superplasticity, O. D. Sherby, 5(6) 75-80, , 1969

3. Superplasticity, K. N. Melton, J. W. Edington, C. P. Cutler, 1-2) 61-170, , 1976

4. Superplasticity, R. H. Johnson, 15(1) 115-134, , 1970

5. Superplasticity, M.-T. Perez-Prado, M. E. Kassner, Chapter 6 – Fundamentals of Creep in Metals and Alloys (Third Edition) Pages 139157, , 2015

6. Superplasticity of low-alloy steels, W. B. Morrison, Trans. ASM 61 (3) 423– 434, , 1968

7. Superplasticity: Science & Technology, P. Chaudhuri, Springer, Berlin, Germany, , 1968

8. Deformation mechanism in superplasticity, A. K. Mukherjee, Ann. Rev. Mater. Sci. 9(1) 191-217, , 1979

9. Superplasticity in a lean Fe-Mn-Al steel, H.-J. Lee, M. Kawasaki, D. Raabe, D. Ponge, Y.-K. Lee, J. Han, S.-H. Kang, S.-J. Lee, 8 751, , 2017

10. Current opinion in medium manganese steel, J. Han, Y.-K. Lee, Mater. Sci. Technol. 31 843-856, , 2015

11. Superplastic Forming of Structural Alloys, N. E. Paton, C. H. Hamilton (eds, The Metallurgical Society of AIME, San Diego, California, , 1982

12. Flow and failure of superplastic materials, D. M. R. Taplin, T. G. Langdon, G. L. Dunlop, 9(1) 151-189, , 1979

13. A first report on deformation-mechanism maps, M. F. Ashby, Acta Metall. 20 887–897, , 1972

14. Crystallographic texture of materials first ed, S. Suwas, R. K. Ray, Springer, , 2014

15. Superplasticity in advanced materials-ICSAM-91, J. Wadsworth In, M. Tokizane, T. G. Langdon, S. Hori, N. Furushiro (eds, The Japan Soc. Res. on Superplasticity pp. 847, , 1991

16. Constitutive behavior of superplastic materials, N. Chandra, 37(3) 461-484, , 2002

17. Diffusion-accommodated flow and superplasticity, R. A. Verrall, M. F. Ashby, 21 149163, , 1973

18. On the mechanism of superplasticity in Ti-6Al-4V, R. C. Reed, D. Barba, K. Dragnevski, E. Alabort, P. Kontis, 105 449463, , 2016

19. A review of superplasticity and related phenomena, E. E. Underwood, 14(12) 914-919, , 1962

20. Superplasticity in the aluminium–zinc eutectoid, M. M. Hutchison, A. Ball, Met. Sci. J. 3 17, , 1969

21. The rate controlling mechanism in superplasticity, A. K. Mukherjee, Mater. Sci. Eng. 8 8389, , 1971

22. Calculation of self-diffusion coefficients in iron, B. Zhang, 4 017128, , 2014

23. The mechanical properties of superplastic materials, T. G. Langdon, Metall. Trans. A 13A 689–701, , 1982

24. Effect of C on the superplasticity of medium Mn steel, H.-B. Jeong, Y.-K. Lee, J.-Y. Lee, H.-J. Cho, 27) 7905-7916, , 2023

25. Superplasticity in rapidly solidified white cast irons, L. E. Eiselstein, O. A. Ruano, O. D. Sherby, Metall. Trans. A 13 1785–1792, , 1982

26. Superplastic deformation behavior of Mg alloys: a-review, J. Long, F. Nazeer, C. Li, Z. Yang, 10 97–109, , 2021

27. Properties of stainless steels with microduplex structure, H. W. Hayden, R. C. Gibson, J. H. Brophy, Trans. ASM 61 85–93, , 1968

28. Effect of B on the superplasticity of Fe-6.6Mn-2.0Al alloy, J.-S. Hong, Y.-K. Lee, H.-B. Jeong, S.-H. Kang, 822 141697, , 2021

29. Superplasticity in electrodeposited nanocrystalline nickel, M. J. N. V. Prasad, A. H. Chokshi, 58 5724-5736, , 2010

30. Stored energy of a severely deformed interstitial free steel, A. A. Gazder, S. S. Hazra, E. V. Pereloma, Mater. Sci. Eng. A 524 158–167, , 2009

31. Superplastic Forming of Advanced Metallic Materials first ed., N. Ridley, Woodhead Publishing, , 2011

32. Microstructural aspects of superplasticity in Ti- 6Al-4V alloy, W. Ziaja, M. Motyka, J. Sieniawski, 599 5763, , 2014

33. Solid-solution strengthening in single crystals of iron alloys, S. Takeuchi, 27(4) 929-940, , 1969

34. Grain refinement and grain size control in superplastic forming, J. A. Wert, 34 3541, , 1982

35. Systematics of recrystallisation micromechanisms in α+β brass, E. Hornbogen, K. Mäder, 8 979983, , 1974

36. The determination of the activation energy for superplastic flow, T. G. Langdon, F. A. Mohamed, 88 375-381, , 1976

37. On the theory of diffusion-viscous flow of polycrystalline bodies, I. M. Lifshitz, Sov. Phys. Jetp-Ussr 17 909920, , 1963

38. Superplasticity resulting from cooperative grain boundary sliding, A. I. Pshenichniuk, O. A. Kaibyshev, V. V. Astanin, 46 49114916, , 1998

39. Cooperative phenomena at grain boundaries during superplastic flow, M. G. Zelin, A. K. Mukherjee, Acta Metall. Mater. 43 23592372, , 1995

40. Superplasticity: Common Basis for a Near-Ubiquitous Phenomenon ed., R. M. Imayev, S. B. Prabu, S. G. Chowdhury, K. A. Padmanabhan, A. Nazarov, R. R. Mulyukov, first Springer, Berlin, Heidelberg, , 2018

41. Modeling texture change during the recrystallization of an IF steel, T. Urabe, J. J. Jonas, ISIJ Int. 34(5) 435-442, , 1994

42. Recent development of superplasticity in aluminium alloys: A review, C. Kong, A. Pesin, P. Tandon, A. P. Zhilyaev, L. Bhatta, H. Yu, 10 77, , 2020

43. Diffusional creep and diffusionally accommodated grain rearrangement, J. R. Spingarn, W. D. Nix, 26 13891398, , 1978

44. Effect of grain size on superplastic deformation of metallic materials, A. Tiwari, R. Jayaganthan, C. S. Rakesh, A. Raja, in Kavian Dooke, IntechOpen (Eds.), Chapter 6 in Aluminium Alloys and Composite, pp. 1–22, , 2020

45. Grain boundary sliding: theory, in: S. Hashmi (Ed.) Reference Module in, A. D. Sheikh-Ali, Materials Science and Materials Engineering, Elsevier pp. 14, , 2016

46. In-situ neutron diffraction during shape-memory behavior in Fe-Mn-Si-Cr, S. Harjo, P. Šittner, P. Lukáš, D. Neov, Y. Tomota, 52 32–34, , 2000

47. Roomtemperature superplasticity in an ultrafine-grained magnesium alloy, K. Edalati, M. Furui, R. Z. Valiev, M. Arita, T. Masuda, Z. Horita, X. Sauvage, 7 2662, , 2017

48. Grain refinement and superplastic behavior in a commercial bearing steel, M. Okade, M. Tokizane, O. D. Sherby, Trans. ISIJ 22 143–146, , 1982

49. Lowtemperature superplasticity in nanostructured nickel and metal alloys, R. S. Mishra, S. X. McFadden, R. Z. Valiev, A. P. Zhilyaev, A. K. Mukherjee, 398 684-686, , 1999

50. Superplasticity: Common Basis for a Near-Ubiquitous Phenomenon first ed., A. Nazarov, K. A. Padmanabhan, R. R. Mulyukov, S. G. Chowdhury, S. B. Prabu, R. M. Imayev, Springer, Berlin, Heidelberg, , 2018

51. A unified approach to grain boundary sliding in creep and superplasticity, T. G. Langdon, 42 24372443, , 1994

52. Enhanced superplasticity in an Al-alloyed multicomponent Mn-Si-Cr-C steel, C. C. Tasan, D. Raabe, D. Ponge, K. G. Pradeep, P. Choi, S. Mandal, H. Zhang, 63 232-244, , 2014

53. Superplasticity-Mechanical and Structural Aspects, Environmental Effects,, G. J. Davies, K. A. Padmanabhan, Fundamentals and Applications Springer, Berlin, , 2012

54. Lowtemperature superplasticity of ultrafine-grained near β titanium alloy, I. P. Mishin, O. N. Lykova, E. V. Naydenkin, O. V. Zabudchenko, I. V. Ratochka, 891 161981, , 2021

55. Superplasticity in Ti-6Al-4V: characterisation, modelling and applications, D. Putman, R. C. Reed, E. Alabort, 95 428442, , 2015

56. The microstructure of an Fe-Mn-Si-Cr-Ni stainless steel shape memory alloy, V. V. Rama Rao, M. Krishnan, B. C. Maji, Metall. Mater. Trans. A 34 1029–1042, , 2003

57. Grain boundary sliding revisited: Developments in sliding over four decades, T. G. Langdon, J. Mater. Sci. 41 597609, , 2006

58. Linear complexions: confined chemical and structural states at dislocations, M. Herbig, S. Sandlöbes, D. Raabe, D. Ponge, M. Kuzmina, 349 1080-1083, , 2015

59. Austenite grain refinement and superplasticity in niobium microalloyed steel, M. Tokizane, N. Matsurnura, Trans. ISIJ 26 315–321, , 1986

60. Grain boundary sliding and its accommodation during creep and superplasticity, R. C. Gifkins, Metall. Trans. 7A 12251232, , 1976

61. Second paper on statistics associated with the random disorientation of cubes, J. K. Mackenzie, 45(1-2) 229-240, , 1958

62. Diffusional and dislocation accommodation mechanisms in superplastic materials, E. Sato, H. Masuda, 197 235252, , 2020

63. Effect of grain refinement on thermal stability of metastable austenitic steel, S. Takaki, T. Tsuchiyama, K. Fukunaga, J. Syarif, Mater. Trans. 45 (7) 2245–2251, , 2004

64. Influence of nickel and vanadium on superplasticity in ultrahigh-carbon steels, J. Wadsworth, O. D. Sherby, J. Mech. Work. Technol. 2(1) 53–66, , 1978

65. Inhomogeneity of microstructure in superplasticity and its effect on ductility, F. P. E. Dunne, 14 (4–5) 413–433, , 1998

66. On the influence of intragranular slip on grain boundary sliding in bicrystals, A. D. Sheikh-Ali, 33 795801, , 1995

67. On the theory of the effect of precipitate particles on grain growth in metals, Gladman, Proc. R. Soc. Lond. A 294 298309, , 1966

68. High-speed tool steel having recrystallized hyperfine grains and its application, I. Shirai, M. Miyagawa, K. Nakazawa, Y. Torisaka, Tetsu-To-Hagane 71 735–742, , 1985

69. Warm ductility enhanced by austenite reversion in ultrafine-grained duplex steel, B. Gault, H.-W. Yen, G.-J. Cheng, C.-Y. Huang, C.-Y. Huang, 148 344–354, , 2018

70. Low-temperature superplastic deformation of cold-rolled Fe-5.6Mn-1.1Al-0.2C steel, H. Zhang, S. Tang, S. Sun, M. Cai, S. Yao, P. D. Hodgson, Y. Luan, W. Zhu, H. Yan, Metall. Mater. Trans. A 53A 3869-3880, , 2022

71. A model for the microstructure behaviour and strength evolution in lath martensite, P. E. J. Rivera-Díaz-del-Castillo, E. I. Galindo-Nava, 98 81–93, , 2015

72. Seventy-five years of superplasticity: historic developments and new opportunities, T. G. Langdon, 44 59986010, , 2009

73. Superplasticity and high strength in Al–Zn–Mg–Zr alloy with ultrafine grains, N. Q. Chinh, V. U. Kazykhanov, M. Y. Murashkin, A. A. Yudakhina, R. Z. Valiev, A. M. Mavlyutov, 22 1900555, , 2020

74. Influence of number of passes in ECAP on superplastic behavior in a magnesium alloy, R. B. Figueiredo, T. G. Langdon, Mater. Sci. Forum 584-586 170-175, , 2008

75. Mechanical behavior of superplastic ultrahigh carbon steels at elevated temperature, B. Walser, O. D. Sherby, Metall. Trans. A 10A 1461–1471, , 1979

76. Grain boundary sliding with and without matrix slip deformation in cadmium bicrystals, H. Fukutomi, R. Horiuchi, H. Takatori, Trans. Jpn. Inst. Met. 23 579584, , 1982

77. Deformation-mechanism Maps: the Plasticity and Creep of Metals and Ceramics, first ed., M. F. Ashby, H. J. Frost, Pergamon Press, Oxford, , 1982

78. Microstructure evolution and strengthening mechanisms in friction-stir welded TWIP steel, I. Vysotskiy, S. Mironov, R. Kaibyshev, V. Torganchuk, S. Malopheyev, 746 248–258, , 2019

79. Superplasticity of a duplex stainless steel produced by a direct strip casting technique, T. Tohge, M. Noda, K. Osada, S. Uekoh, K. Ebato, Trans. ISIJ 28 16–22, , 1988

80. Enhancement of superplastic properties in ultrahigh carbon steel through silicon addition, J. A. Jimenez, T. Oyama, O. A. Ruano, O. D. Sherby, Steel Res. Int. 80 (1) 78–83, , 2009

81. High-strain-rate superplasticity in ultrahigh-carbon steel containing 10 wt%Al (UHCS-10Al), M. Nagao, K. Higashi, E. M. Taleff, O. D. Sherby, 34(12) 1919-1923, , 1996

82. Investigation of grain boundary sliding in zinc bicrystals with a symmetrical tilt boundary, O. A. Kaybyshev, R. Z. Valiyev, V. V. Astanin, V. G. Khayrullin, 51 166172, , 1981

83. Ultralow-temperature superplasticity and its novel mechanism in ultrafine-grained Al alloys, M. Y. Murashkin, N. Q. Chinh, A. Q. Ahmed, J. Gubicza, Z. Kovács, V. Maier-Kiener, J. L. Lábár, R. Z. Valiev, E. V. Bobruk, 9(11) (2021) 475-482., , 2021

84. Effect of superplastic deformation on microstructure evolution of 3207 duplex stainless steel, J. Li, X. Gao, X. Ren, Mater. Char. 164 110320, , 2020

85. Quantitative Relation between Properties and Microstructure, D. G. Brandon and A. Rosen (Ed.), J. E. Bird, A. K. Mukherjee, J. E. Dorn, 255 Israel Universities Press, Jerusalem, 255342, , 1969

86. Superior room temperature ductility of magnesium dilute binary alloy via grain boundary sliding, H. Somekawa, A. Singh, 150 26–30, , 2018

87. High-temperature tensile deformation behavior and microstructure evolution of Ti55 titanium alloy, L. J. He, Z. G. Liu, T. Y. Liu, P. J. Li, L. T. Xiong, 680 259269, , 2017

88. Mechanical Behavior of Materials, Chapter 7 High-temperature deformation of crystalline materials, T. H. Courtney, Waveland Press pp. 293–353, , 2005

89. Microstructural stability and superplasticity in an electrodeposited nanocrystalline Ni–P alloy, M. J. N. V. Prasad, A. H. Chokshi, 59 4055–4067, , 2011

90. Structural superplasticity at higher strain rates of hypereutectoid Fe-5.5 Al-1Sn-1Cr-1.3 C steel, J. A. Jim´enez, G. Frommeyer, Metall. Mater. Trans. 36 (2) 295– 300, , 2005

91. Superplastic property of the Ti-6Al- 4V alloy with ultrafine-grained heterogeneous microstructure, V. Velay, H. Matsumoto, V. Vidal, T. Nishihara, 20 1700317, , 2018

92. Extraordinary warm ductility of a Mn-rich high-strength steel achieved at temperature below 0.5 Tm, G.-J. Cheng, H.-W. Yen, T. Jia, Z.-H. Lai, C.-Y. Huang, 803 140704, , 2021

93. Sliding along the interphase boundary in austenite/ferrite duplex stainless steel bicrystals in S., F. Moriwaki, S. Miura HoriEd, S. Hashimoto, T. Mimaki, Superplasticity in Advanced Materials, The Japan Soc. Res. on Superplasticity, pp. 23–32, , 1991

94. Characteristics of superplasticity in an ultrafine-grained aluminum alloy processed by ECA pressing, R. K. Islamgaliev, N. F. Yunusova, N. K. Tsenev, V. N. Perevezentsev, R. Z. Valiev, T. G. Langdon, 49 467–472, , 2003

95. Determination of the strain rate sensitivity of a superplastic material during load relaxation test, F. U. Enikeev, M. I. Mazurski, 32 16, , 1995

96. Superplastic Mn-Si-Cr-C duplex and triplex steels: interaction of microstructure and void formation, H. Zhang, D. Raabe, D. Ponge, 610 355-369, , 2014

97. Achieving superplastic properties in a ZK10 magnesium alloy processed by equal-channel angular pressing, R. B. Figueiredo, T. G. Langdon, 6(2) 129135, , 2017

98. Grain boundary sliding during high temperature tensile deformation in superplastic Fe-6.6Mn-2.3Al steel, S.-W. Choi, Y.-K. Lee, S.-H. Kang, Y.-D. Im, 780, 139174, , 2020

99. Grain boundary sliding in a superplastic zinc-aluminum alloy processed using severe plastic deformation, T. G. Langdon, M. Kawasaki, Mater. Trans. 49(1) 84-89, , 2008

100. Low temperature superplasticity and thermal stability of a nanostructured low-carbon microalloyed steel, L.-X. Du, R. D. K. Misra, H. Xie, J. Hu, G.-S. Sun, 5, 18656, , 2016

101. Superplasticity-Mechanical and Structural Aspects, Environmental Effects, Fundamentals and Applications, K. A. Padmanabhan, G. J. Davies, Springer, Berlin, , 2012

102. Variation of strain rate sensitivity index of a superplastic aluminium alloy in different testing methods, N. Bombardier, M. Jahazi, E. Samuel, O. Majidi, AIP Conf. Proc. 1896 020022, , 2017

103. Size effects on stress concentration induced by a prolate ellipsoidal particle and void nucleation mechanism, M. Huang, Z. Li, 1568-1590, , 2005

104. Martensite reversion and texture formation in 17Mn-0.06C TRIP/TWIP steel after hot cold rolling and annealing, D. P. Escobar, S. S. F. de Dafé, D. B. Santos, 42) 162-170, , 2015

105. 相界面のバイクリスタル研究 二相 (γ/α) ステンレス鋼双結晶の超塑性界面すべり, S. Miura, S. Hashimoto, 31 116, , 1992

106. The effects of thermo-mechanical treatments on superplasticity of Fe-24Cr-7Ni-3Mo-0.14N duplex stainless steel, Y. S. Han, S. H. Hong, 36 557-563, , 1997

107. High-strain rate superplasticity and role of dynamic recrystallization in a superplastic duplex stainless steel, H. Matsuyama, M. Nagao, T. Maki, K. Tsuzaki, Mater. Trans. JIM 31 983-994, , 1990

108. Strength and strain-hardening enhancement by generating hard delta-ferrite in twinning-induced plasticity steel, A. Shan, Y. Guo, C. Pei, L. Fu, B. Fu, 36(7) 827-834, , 2020

109. Microstructural evolution in recrystallized and unrecrystallized Al-Mg-Sc alloys during superplastic deformation, F. C. Liu, Z. Y. Ma, P. Xue, 547 5563, , 2012

110. Phase reverted transformation-induced nanograin microalloyed steel: low temperature superplasticity and fracture, H. Xie, R. D. K. Misra, I. V. S. Yashwanth, G.-S. Sun, V. S. A. Challa, J. Hu, L.-X. Du, 668 105-111, , 2016

111. Effect of equal-channel angular pressing on room temperature superplasticity of quasi-single phase Zn-0.3Al alloy, H. Yanar, Z. F. Zhang, G. Purcek, M. Demirtas, Z. J. Zhang, 644 17-24, , 2015

112. Pinning effect of second-particles on grain growth in polycrystalline films studied by 3-D phase field simulations, P. Wollants, N. Moelans, B. Blanpain, 55 21732182, , 2007

113. The influence of silicon additions on the deformation behavior of austenite-ferrite duplex medium manganese steels, C. Scott, S. Yue, F. Fazeli, N. Brodusch, B. Sun, R. Gauvin, 148 249-262, , 2018

114. Deformation mechanisms for superplastic behaviors in a dual-phase high specific strength steel with ultrafine grains, D. Yan, F. Yuan, X. Wu, W. Wang, M. Yang, P. Jiang, 702 133–141, , 2017

115. High strain rate superplasticity in Al-Zn-Mg-based alloy: microstructural design, deformation behavior, and modeling, A. Mikhaylovskaya, O. Yakovtseva, A. O. Mosleh, M. Sitkina, 13 2098, , 2020

116. Ti-6Al-4V alloy with an ultrafine-grained microstructure exhibiting low-temperature-high-strain-rate superplasticity, K. Yoshida, H. Matsumoto, A. Chiba, S.-H. Lee, Y. Ono, 98 209-212, , 2013

117. Quantitative phase fraction analysis of steel combined with texture analysis using time-of-flight neutron diffraction, T. Tomida, Y. Onuki, S. Sato, T. Ishigaki, A. Hoshikawa, 52 11643–11658, , 2017

118. The stress-strain rate behavior of a manganese steel in the temperature range of the ferrite-austenite transformation, H. W. Schadler, Trans. Metall. AIME 242 (7) 1281– 1287, , 1968

119. Accommodation mechanisms for grain boundary sliding as inferred from texture evolution during superplastic deformation, Y. Takigawa, K. Kurimoto, H. Watanabe, T. Uesugi, K. Higashi, 93 2913–2931, , 2013

120. Microstructure evolution and mechanical behavior of ultrafine Ti-6Al-4V during lowtemperature superplastic deformation, E. A. Kudryavtsev, S. V. Zherebtsov, B. B. Straumal, S. L. Semiatin, G. A. Salishchev, 121 152–163, , 2016

121. The superplastic response of three rapidly solidified microduplex stainless steels of varying ferrite-austenite content, N. J. Grant, F. Dabkowski, Y. Zhang, 65 265–270, , 1984

122. Achieving ultra-high elongation of 1401% in a warm-rolled medium Mn lightweight steel with dual-phase lamellar structure, J. Li, Y. Zhao, L. Liu, M. Cai, H. Ding, Z. Wu, Pan, X. Li, H. Zhang, Z. Wang, Y. Zhang, 862 (2023) 144493, , 2023

123. Effect of silicon addition on recrystallization and phase transformation behavior of high-strength hot-rolled trip steel, D. Wu, X. M. Zhao, L. J. Zhu, Acta Metall. Sin. 21 (3) 163–168, , 2008

124. High strength-superplasticity combination of ultrafine-grained ferritic steel: the significant role of nanoscale carbides, P. K. Liaw, R. D. K. Misra, J. W. Liang, Y. F. Shen, 83 131-144, , 2021

125. Lowering the temperature for high strain rate superplasticity in an Al-Mg-Zn-Cu alloy via cooled friction stir processing, F. Carreño, P. Rey, P. Hidalgo-Manrique, O. A. Ruano, D. Verdera, D. Gesto, A. Orozco-Caballero, C. M. Cepeda-Jiménez, 142 182-185., , 2013

126. Strain rate and temperature dependence of low temperature superplastic deformation in a nanostructured microalloyed steel, G.-S. Sun, J. Hu, T. Wang, L.-X. Du, R. D. K. Misra, 243 165-168, , 2019

127. High temperature superplasticity and deformation behavior of naturally aged Zn-Al alloys with different phase compositions, M. Kawasaki, M. Demirtas, G. Purcek, H. Yanar, 730 73–83, , 2018

128. A significant improvement in the mechanical properties of AISI 304 stainless steel by a combined RCSR and annealing process, S. H. Nedjad, M. Nili-Ahmadabadi, P. Asghari-Rad, S. Koldorf, H. Shirazi, 19 (3) 1600663, , 2017

129. Achieving excellent superplasticity in an ultrafine-grained QE22 alloy at both high strain rate and low-temperature regimes, S. K. Panigrahi, F. Khan, 71-82, , 2018

130. Developing superplasticity and a deformation mechanism map for the Zn-Al eutectoid alloy processed by high-pressure torsion, T. G. Langdon, M. Kawasaki, 528 61406145, , 2011

131. Revealing the superplastic deformation behaviors of hot rolled 0.10C5Mn2Al steel with an initial martensitic microstructure, D. Ponge, C. Wang, Z. Cao, X. Sun, W. Cao, G. Wu, 152 27–30, , 2018

132. Strain rate dependent microstructural evolution during hot deformation of a hot isostatically processed nickel base superalloy, G. A. Rao, S. S. S. Kumar, P. P. Bhattacharjee, U. Borah, T. Raghu, 681 28–42, , 2016

133. improvement of high strain rate and room temperature superplasticity in Zn-22Al alloy by two-step equal-channel angular pressing, Z. F. Zhang, Z. J. Zhang, H. Yanar, M. Demirtas, G. Purcek, 620 233-240, , 2015

134. Prominent role of multi-scale microstructural heterogeneities on superplastic deformation of a high solid solution Al–7Mg alloy, R. H. Mathiesen, G. Sha, R. Bjørge, H. Jia, S. Jin, Y. Gao, M. Zha, Y. Li, H. Zhang, H. Wang, H. J. Roven, Int. J. Plast, , 2021

135. Dynamic reverse phase transformation induced high-strain-rate superplasticity in low carbon low alloy steels with commercial potential, C. Wang, H. Dong, C. Huang, Y. Weng, W. Cao, 7 9199, , 2017

136. Effect of strain rate on the microstructure evolution and superplastic deformation behavior of cold-rolled medium Mn lightweight steel, L. Liu, X. Li, Z. Wu, H. Pan, S. Zhang, W. Zhou, 879 (2023) 145241, , 2023

137. Interphase boundary sliding of two-phase (α/β), (β/γ) and (γ/α) CuZnSn alloy couples produced by solid-to-solid diffusion bonding, T. Mimaki, N. Ashie, H. Miyamoto, S. Miura, R. Matsubara, T. Tanaka, 380(1-2) 34-40., , 2004

138. The direct observation of cooperative grain-boundary sliding and migration during superplastic deformation of leadtin eutectic in shear, A. K. Mukherjee, R. Rosen, M. G. Zelin, M. R. Dunlap, 74 49724982, , 1993

139. Influence of Al on the microstructural evolution and mechanical behavior of low-carbon, manganese transformation-induced-plasticity steel, C.-S. Oh, S.-J. Park, D.-W. Suh, S.-J. Kim, T.-H. Lee, Metall. Mater. Trans. A 41 397-408, , 2010

140. The effects of the heating rate on the reverse transformation mechanism and the phase stability of reverted austenite in medium Mn steels, J. Han, Y.-K. Lee, 67 354-361, , 2014

141. Effect of different processes on lamellar-free ultrafine grain formation, room temperature superplasticity and fracture mode of Zn-22Al alloy, M. Demirtas, H. Yanar, G. Purcek, Z. J. Zhang, Z. F. Zhang, 663 775–783, , 2016

142. The influence of minor additions of Y, Sc, and Zr on the microstructural evolution, superplastic behavior, and mechanical properties of AA6013 alloy, A. G. Mochugovskiy, A. V. Mikhaylovskaya, M. E. Ghayoumabadi, N. Y. Tabachkova, 900 163477, , 2022

143. The effects of the initial martensite microstructure on the microstructure and tensile properties of intercritically annealed Fe– 9Mn–0.05C steel, J. Han, J.-G. Jung, S.-J. Lee, Y.-K. Lee, 78 369-377, , 2014

144. Successful transition from low-temperature superplasticity to high-strain-rate superplasticity with increasing temperature in an ultrafine-grained Mg-YZn- Zr alloy, T. J. Lee, W. J. Kim, 817 153298, , 2020

145. Flow behavior and microstructure in Ti-6Al-4V alloy with an ultrafine-grained α-single phase microstructure during low-temperature-highstrain- rate superplasticity, H. Matsumoto, A. Chiba, V. Velay, 66 611-617, , 2015

146. On the microstructure evolution in friction stir processed 2507 super duplex stainless steel and its effect on tensile behaviour at ambient and elevated temperatures, B. P. Kashyap, N. Prabhu, I. Balasundar, M. K. Mishra, A. G. Rao, 719 82–92, , 2018

147. Flow behavior and microstructure in Ti-6Al-4V alloy with an ultrafine-grained α-single phase microstructure during low-temperature-high10 strain-rate superplasticity, H. Matsumoto, V. Velay, A. Chiba, 66 611-617, , 2015